Server-side demo recording and playback (netdemo)

Complete netdemo feature as a single commit on implant2.
See svdemo.txt for full documentation.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

code/cgame/cg_draw.c

@@ -1650,6 +1650,16 @@ static void CG_DrawDisconnect( void ) {
 	const char		*s;
 	int			w;  // bk010215 - FIXME char message[1024];
 
+	// server demo playback: detect pause from frozen snapshot time
+	if ( cg.svDemoPlayback ) {
+		if ( cg.nextSnap && cg.nextSnap->serverTime == cg.snap->serverTime ) {
+			s = "Playback Paused";
+			w = CG_DrawStrlen( s ) * BIGCHAR_WIDTH;
+			CG_DrawBigString( 320 - w/2, 100, s, 1.0F );
+		}
+		return;
+	}
+
 	// draw the phone jack if we are completely past our buffers
 	cmdNum = trap_GetCurrentCmdNumber() - CMD_BACKUP + 1;
 	trap_GetUserCmd( cmdNum, &cmd );

code/cgame/cg_local.h

@@ -457,6 +457,10 @@ typedef struct {
 	int			clientNum;
 	
 	qboolean	demoPlayback;
+	qboolean	svDemoPlayback;		// server-side demo playback mode
+	qboolean	svDemoFreeCamera;	// free camera (client-owned movement)
+	playerState_t	svDemoCameraPs;	// local playerState for free camera
+	int			svDemoCameraTime;	// real time of last camera update
 	qboolean	levelShot;			// taking a level menu screenshot
 	int			deferredPlayerLoading;
 	qboolean	loading;			// don't defer players at initial startup
@@ -1618,6 +1622,7 @@ qboolean	trap_GetUserCmd( int cmdNumber, usercmd_t *ucmd );
 
 // used for the weapon select and zoom
 void		trap_SetUserCmdValue( int stateValue, float sensitivityScale );
+void		trap_SetClientOrigin( qboolean hasOrigin, float x, float y, float z );
 
 // aids for VM testing
 void		testPrintInt( char *string, int i );

code/cgame/cg_main.c

@@ -1896,6 +1896,13 @@ void CG_Init( int serverMessageNum, int serverCommandSequence, int clientNum ) {
 	// get the gamestate from the client system
 	trap_GetGameState( &cgs.gameState );
 
+	// detect server-side demo playback from configstring
+	cg.svDemoPlayback = ( atoi( CG_ConfigString( CS_SVDEMO ) ) != 0 );
+	if ( cg.svDemoPlayback ) {
+		cg.svDemoFreeCamera = qtrue;
+		// camera ps will be initialized from first snapshot in CG_PredictPlayerState
+	}
+
 	// check version
 	s = CG_ConfigString( CS_GAME_VERSION );
 	if ( strcmp( s, GAME_VERSION ) ) {

code/cgame/cg_predict.c

@@ -432,6 +432,59 @@ void CG_PredictPlayerState( void ) {
 	// demo playback just copies the moves
 	if ( cg.demoPlayback || (cg.snap->ps.pm_flags & PMF_FOLLOW) ) {
 		CG_InterpolatePlayerState( qfalse );
+		// send followed player's origin for PVS during server demo follow mode
+		if ( cg.svDemoPlayback && (cg.snap->ps.pm_flags & PMF_FOLLOW) ) {
+			trap_SetClientOrigin( qtrue,
+				cg.snap->ps.origin[0],
+				cg.snap->ps.origin[1],
+				cg.snap->ps.origin[2] );
+			cg.svDemoFreeCamera = qfalse;
+		}
+		return;
+	}
+
+	// server-side demo free camera: run local PmoveSingle
+	if ( cg.svDemoPlayback && cg.svDemoFreeCamera ) {
+		int realTime = trap_Milliseconds();
+		int dt = realTime - cg.svDemoCameraTime;
+		pmove_t pm;
+
+		// lazy init: place camera at spectator spawn from first snapshot
+		if ( cg.svDemoCameraPs.speed == 0 ) {
+			cg.svDemoCameraPs = cg.snap->ps;
+			cg.svDemoCameraPs.pm_type = PM_SPECTATOR;
+			cg.svDemoCameraPs.speed = 480;
+			cg.svDemoCameraTime = realTime;
+			dt = 1;
+		}
+
+		if ( dt < 1 ) dt = 1;
+		if ( dt > 200 ) dt = 200;
+		cg.svDemoCameraTime = realTime;
+
+		// get latest usercmd for input
+		current = trap_GetCurrentCmdNumber();
+		trap_GetUserCmd( current, &latestCmd );
+
+		// set up pmove
+		memset( &pm, 0, sizeof(pm) );
+		pm.ps = &cg.svDemoCameraPs;
+		pm.cmd = latestCmd;
+		pm.cmd.serverTime = cg.svDemoCameraPs.commandTime + dt;
+		pm.tracemask = MASK_PLAYERSOLID & ~CONTENTS_BODY;
+		pm.trace = CG_Trace;
+		pm.pointcontents = CG_PointContents;
+
+		Pmove( &pm );
+
+		// use as the predicted state for rendering
+		cg.predictedPlayerState = cg.svDemoCameraPs;
+
+		// send origin for PVS
+		trap_SetClientOrigin( qtrue,
+			cg.svDemoCameraPs.origin[0],
+			cg.svDemoCameraPs.origin[1],
+			cg.svDemoCameraPs.origin[2] );
 		return;
 	}
 

code/cgame/cg_public.h

@@ -164,6 +164,7 @@ typedef enum {
 	CG_R_INPVS,
 	// 1.32
 	CG_FS_SEEK,
+	CG_SETCLIENTORIGIN,	// set client-owned origin for demo spectator PVS
 
 /*
 	CG_LOADCAMERA,

code/cgame/cg_snapshot.c

@@ -184,6 +184,22 @@ static void CG_TransitionSnapshot( void ) {
 			|| cg_nopredict.integer || cg_synchronousClients.integer ) {
 			CG_TransitionPlayerState( ps, ops );
 		}
+
+		// server demo: detect follow->free camera transition
+		if ( cg.svDemoPlayback ) {
+			qboolean wasFollowing = ( ops->pm_flags & PMF_FOLLOW ) != 0;
+			qboolean isFollowing = ( ps->pm_flags & PMF_FOLLOW ) != 0;
+			if ( wasFollowing && !isFollowing ) {
+				// exiting follow mode -- init camera from last known position
+				cg.svDemoFreeCamera = qtrue;
+				cg.svDemoCameraTime = trap_Milliseconds();
+				VectorCopy( ops->origin, cg.svDemoCameraPs.origin );
+				VectorCopy( ops->viewangles, cg.svDemoCameraPs.viewangles );
+				cg.svDemoCameraPs.pm_type = PM_SPECTATOR;
+				cg.svDemoCameraPs.speed = 480;
+				cg.svDemoCameraPs.clientNum = cg.clientNum;
+			}
+		}
 	}
 
 }
@@ -203,6 +219,15 @@ static void CG_SetNextSnap( snapshot_t *snap ) {
 
 	cg.nextSnap = snap;
 
+	// SNAPFLAG_RESET_ENTITIES: invalidate all entities so they are
+	// treated as new (no interpolation from old positions).
+	// Must happen before the entity loop below.
+	if ( snap->snapFlags & SNAPFLAG_RESET_ENTITIES ) {
+		for ( num = 0 ; num < MAX_GENTITIES ; num++ ) {
+			cg_entities[ num ].currentValid = qfalse;
+		}
+	}
+
 	BG_PlayerStateToEntityState( &snap->ps, &cg_entities[ snap->ps.clientNum ].nextState, qfalse );
 	cg_entities[ cg.snap->ps.clientNum ].interpolate = qtrue;
 
@@ -241,6 +266,11 @@ static void CG_SetNextSnap( snapshot_t *snap ) {
 		cg.nextFrameTeleport = qtrue;
 	}
 
+	// entity reset also prevents playerstate interpolation
+	if ( cg.nextSnap->snapFlags & SNAPFLAG_RESET_ENTITIES ) {
+		cg.nextFrameTeleport = qtrue;
+	}
+
 	// sort out solid entities
 	CG_BuildSolidList();
 }
@@ -372,8 +402,34 @@ void CG_ProcessSnapshots( void ) {
 			CG_SetNextSnap( snap );
 
 
-			// if time went backwards, we have a level restart
+			// if time went backwards, we have a level restart or demo seek
 			if ( cg.nextSnap->serverTime < cg.snap->serverTime ) {
+				if ( cg.svDemoPlayback ) {
+					// demo seek -- discard old snap, use nextSnap as current,
+					// and wait for another snapshot before rendering
+					cg.snap = cg.nextSnap;
+					cg.nextSnap = NULL;
+					cg.time = cg.snap->serverTime;
+					// reset all entity state and time-dependent fields
+					{
+						int e;
+						for ( e = 0; e < MAX_GENTITIES; e++ ) {
+							cg_entities[e].currentValid = qfalse;
+							cg_entities[e].interpolate = qfalse;
+							cg_entities[e].muzzleFlashTime = 0;
+							cg_entities[e].trailTime = 0;
+							cg_entities[e].dustTrailTime = 0;
+							cg_entities[e].miscTime = 0;
+							cg_entities[e].snapShotTime = 0;
+							cg_entities[e].previousEvent = 0;
+							cg_entities[e].teleportFlag = 0;
+						}
+					}
+					// clear local entities (particles, gibs, etc.)
+					// they reference old times and would render incorrectly
+					CG_InitLocalEntities();
+					break;  // exit loop, wait for next snapshot
+				}
 				CG_Error( "CG_ProcessSnapshots: Server time went backwards" );
 			}
 		}

code/cgame/cg_syscalls.c

@@ -333,6 +333,10 @@ void		trap_SetUserCmdValue( int stateValue, float sensitivityScale ) {
 	syscall( CG_SETUSERCMDVALUE, stateValue, PASSFLOAT(sensitivityScale) );
 }
 
+void		trap_SetClientOrigin( qboolean hasOrigin, float x, float y, float z ) {
+	syscall( CG_SETCLIENTORIGIN, hasOrigin, PASSFLOAT(x), PASSFLOAT(y), PASSFLOAT(z) );
+}
+
 void		testPrintInt( char *string, int i ) {
 	syscall( CG_TESTPRINTINT, string, i );
 }

code/client/cl_cgame.c

@@ -457,6 +457,14 @@ int CL_CgameSystemCalls( int *args ) {
 		return 0;
 	case CG_FS_SEEK:
 		return FS_Seek( args[1], args[2], args[3] );
+	case CG_SETCLIENTORIGIN:
+		cl.cgameHasOrigin = args[1];
+		if ( args[1] ) {
+			cl.cgameOrigin[0] = VMF(2);
+			cl.cgameOrigin[1] = VMF(3);
+			cl.cgameOrigin[2] = VMF(4);
+		}
+		return 0;
 	case CG_SENDCONSOLECOMMAND:
 		Cbuf_AddText( VMA(1) );
 		return 0;

code/client/cl_input.c

@@ -516,6 +516,12 @@ void CL_FinishMove( usercmd_t *cmd ) {
 	for (i=0 ; i<3 ; i++) {
 		cmd->angles[i] = ANGLE2SHORT(cl.viewangles[i]);
 	}
+
+	// client-owned origin for demo spectator PVS
+	cmd->hasOrigin = cl.cgameHasOrigin;
+	if ( cl.cgameHasOrigin ) {
+		VectorCopy( cl.cgameOrigin, cmd->origin );
+	}
 }
 
 

code/client/cl_parse.c

@@ -288,6 +288,9 @@ void CL_ParseSnapshot( msg_t *msg ) {
 		cl.snapshots[oldMessageNum & PACKET_MASK].valid = qfalse;
 	}
 
+	{
+		int oldSnapFlags = cl.snap.snapFlags;
+
 		// copy to the current good spot
 		cl.snap = newSnap;
 		cl.snap.ping = 999;
@@ -299,6 +302,16 @@ void CL_ParseSnapshot( msg_t *msg ) {
 				break;
 			}
 		}
+		// if server count changed (map_restart or demo unpause), force-reset
+		// the time delta so the client doesn't slowly drift back to sync
+		if ( ( oldSnapFlags ^ newSnap.snapFlags ) & SNAPFLAG_SERVERCOUNT ) {
+			cl.serverTimeDelta = cl.snap.serverTime - cls.realtime;
+			cl.oldServerTime = cl.snap.serverTime;
+			cl.serverTime = cl.snap.serverTime;
+			cl.oldFrameServerTime = cl.snap.serverTime;  // prevent backwards time error on seek
+		}
+	}
+
 	// save the frame off in the backup array for later delta comparisons
 	cl.snapshots[cl.snap.messageNum & PACKET_MASK] = cl.snap;
 

code/client/client.h

@@ -106,6 +106,8 @@ typedef struct {
 	// cgame communicates a few values to the client system
 	int			cgameUserCmdValue;	// current weapon to add to usercmd_t
 	float		cgameSensitivity;
+	qboolean	cgameHasOrigin;		// client-owned origin for demo spectator PVS
+	vec3_t		cgameOrigin;		// the origin to send
 
 	// cmds[cmdNumber] is the predicted command, [cmdNumber-1] is the last
 	// properly generated command

code/game/bg_local.h

@@ -26,7 +26,7 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 #define	STEPSIZE		18
 
-#define	JUMP_VELOCITY	270
+#define	JUMP_VELOCITY	275
 
 #define	TIMER_LAND		130
 #define	TIMER_GESTURE	(34*66+50)
@@ -77,6 +77,8 @@ void PM_ClipVelocity( vec3_t in, vec3_t normal, vec3_t out, float overbounce );
 void PM_AddTouchEnt( int entityNum );
 void PM_AddEvent( int newEvent );
 
+qboolean	PM_CanJump( void );
+void		PM_Jump( void );
 qboolean	PM_SlideMove( qboolean gravity );
 void		PM_StepSlideMove( qboolean gravity );
 

code/game/bg_pmove.c

@@ -353,32 +353,55 @@ static void PM_SetMovementDir( void ) {
 
 /*
 =============
-PM_CheckJump
+PM_Jump
+
+Applies jump velocity, event, and animation.
+Extracted from PM_CheckJump so it can be called
+from other contexts (step jump, double jump, etc).
 =============
 */
-static qboolean PM_CheckJump( void ) {
+/*
+=============
+PM_CanJump
+
+Returns qtrue if a jump would succeed right now.
+Checks both player state AND input (upmove >= 10).
+Used by PM_StepSlideMove to decide whether stepping
+up stairs should trigger a jump.
+=============
+*/
+qboolean PM_CanJump( void ) {
 	if ( pm->ps->pm_flags & PMF_RESPAWNED ) {
-		return qfalse;		// don't allow jump until all buttons are up
+		return qfalse;
+	}
+
+	if ( pm->ps->pm_type != PM_NORMAL ) {
+		return qfalse;
 	}
 
 	if ( pm->cmd.upmove < 10 ) {
-		// not holding jump
 		return qfalse;
 	}
 
-	// must wait for jump to be released
-	if ( pm->ps->pm_flags & PMF_JUMP_HELD ) {
-		// clear upmove so cmdscale doesn't lower running speed
-		pm->cmd.upmove = 0;
+	// QL: 100ms minimum delay between jumps.
+	// Prevents same-frame double-fires. Step jumps launch the player
+	// high enough (~400ms airtime) that the next stair collision
+	// naturally exceeds this threshold.
+	if ( pm->cmd.serverTime - pm->ps->lastJumpTime < 100 ) {
 		return qfalse;
 	}
 
+	return qtrue;
+}
+
+void PM_Jump( void ) {
 	pml.groundPlane = qfalse;		// jumping away
 	pml.walking = qfalse;
 	pm->ps->pm_flags |= PMF_JUMP_HELD;
 
 	pm->ps->groundEntityNum = ENTITYNUM_NONE;
 	pm->ps->velocity[2] = JUMP_VELOCITY;
+	pm->ps->lastJumpTime = pm->cmd.serverTime;
 	PM_AddEvent( EV_JUMP );
 
 	if ( pm->cmd.forwardmove >= 0 ) {
@@ -388,6 +411,23 @@ static qboolean PM_CheckJump( void ) {
 		PM_ForceLegsAnim( LEGS_JUMPB );
 		pm->ps->pm_flags |= PMF_BACKWARDS_JUMP;
 	}
+}
+
+/*
+=============
+PM_CheckJump
+=============
+*/
+static qboolean PM_CheckJump( void ) {
+	if ( !PM_CanJump() ) {
+		return qfalse;
+	}
+
+	// QL autohop: no PMF_JUMP_HELD gate here.
+	// The Pmove() outer loop forces upmove=20 when
+	// PMF_JUMP_HELD is set, allowing continuous bunny hopping.
+
+	PM_Jump();
 
 	return qtrue;
 }

code/game/bg_public.h

@@ -79,6 +79,7 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #define CS_FLAGSTATUS			23		// string indicating flag status in CTF
 #define CS_SHADERSTATE			24
 #define CS_BOTINFO				25
+#define CS_SVDEMO				26		// "1" during server-side demo playback
 
 #define	CS_ITEMS				27		// string of 0's and 1's that tell which items are present
 

code/game/bg_slidemove.c

@@ -234,9 +234,8 @@ void PM_StepSlideMove( qboolean gravity ) {
 	vec3_t		start_o, start_v;
 	vec3_t		down_o, down_v;
 	trace_t		trace;
-//	float		down_dist, up_dist;
-//	vec3_t		delta, delta2;
 	vec3_t		up, down;
+	vec3_t		projected;
 	float		stepSize;
 
 	VectorCopy (pm->ps->origin, start_o);
@@ -246,15 +245,12 @@ void PM_StepSlideMove( qboolean gravity ) {
 		return;		// we got exactly where we wanted to go first try
 	}
 
-	VectorCopy(start_o, down);
-	down[2] -= STEPSIZE;
-	pm->trace (&trace, start_o, pm->mins, pm->maxs, down, pm->ps->clientNum, pm->tracemask);
-	VectorSet(up, 0, 0, 1);
-	// never step up when you still have up velocity
-	if ( pm->ps->velocity[2] > 0 && (trace.fraction == 1.0 ||
-										DotProduct(trace.plane.normal, up) < 0.7)) {
-		return;
-	}
+	// QL: compute projected position (where player would be without collision)
+	VectorMA( start_o, pml.frametime, start_v, projected );
+
+	// QL pm_airSteps: allow step-ups with upward velocity.
+	// Q3 blocked step-ups during jumps unless ground was directly below.
+	// This prevented smooth stair traversal while bunny-hopping.
 
 	VectorCopy (pm->ps->origin, down_o);
 	VectorCopy (pm->ps->velocity, down_v);
@@ -285,27 +281,29 @@ void PM_StepSlideMove( qboolean gravity ) {
 	if ( !trace.allsolid ) {
 		VectorCopy (trace.endpos, pm->ps->origin);
 	}
+	// QL: only clip velocity to step surface when moving INTO it.
+	// Skip clip when velocity is already moving away (preserves
+	// upward momentum through stair steps during bunny-hopping).
 	if ( trace.fraction < 1.0 ) {
+		float vdotn = DotProduct( pm->ps->velocity, trace.plane.normal );
+		if ( vdotn < 0 || fabs( vdotn ) < 0.001f ) {
 			PM_ClipVelocity( pm->ps->velocity, trace.plane.normal, pm->ps->velocity, OVERCLIP );
 		}
-
-#if 0
-	// if the down trace can trace back to the original position directly, don't step
-	pm->trace( &trace, pm->ps->origin, pm->mins, pm->maxs, start_o, pm->ps->clientNum, pm->tracemask);
-	if ( trace.fraction == 1.0 ) {
-		// use the original move
-		VectorCopy (down_o, pm->ps->origin);
-		VectorCopy (down_v, pm->ps->velocity);
-		if ( pm->debugLevel ) {
-			Com_Printf("%i:bend\n", c_pmove);
 	}
-	} else 
-#endif
-	{
-		// use the step move
+
+	// QL master gate: trace from original position to final position.
+	// If the trace hits geometry (fraction < 1.0), a real step was crossed.
+	// On flat ground with micro-bumps, the trace is clear and this entire
+	// block is skipped — filtering out false positives.
+	pm->trace( &trace, start_o, pm->mins, pm->maxs, pm->ps->origin,
+			   pm->ps->clientNum, pm->tracemask );
+
+	if ( trace.fraction < 1.0 ) {
 		float	delta;
 
 		delta = pm->ps->origin[2] - start_o[2];
+
+		// step sound events
 		if ( delta > 2 ) {
 			if ( delta < 7 ) {
 				PM_AddEvent( EV_STEP_4 );
@@ -317,6 +315,35 @@ void PM_StepSlideMove( qboolean gravity ) {
 				PM_AddEvent( EV_STEP_16 );
 			}
 		}
+
+		// QL air-step friction: 3% horizontal speed penalty per airborne step-up
+		if ( !pml.groundPlane && delta > 0 && start_v[2] > 0 ) {
+			pm->ps->velocity[0] *= 0.97f;
+			pm->ps->velocity[1] *= 0.97f;
+		}
+
+		// QL step jump gate: validate stair geometry at projected position.
+		// Traces DOWN at where the player would be without collision.
+		// Walls fail (startsolid), flat ground fails (delta<=0), stairs pass.
+		if ( delta > 0 && pm->ps->pm_type == PM_NORMAL
+			&& pm->waterlevel < 2 && PM_CanJump() ) {
+			vec3_t		stepStart, stepEnd;
+			trace_t		stepTrace;
+
+			VectorCopy( projected, stepStart );
+			VectorCopy( projected, stepEnd );
+			stepStart[2] += STEPSIZE;
+			stepEnd[2] -= STEPSIZE;
+
+			pm->trace( &stepTrace, stepStart, pm->mins, pm->maxs,
+					   stepEnd, pm->ps->clientNum, pm->tracemask );
+
+			if ( !stepTrace.startsolid && !stepTrace.allsolid
+				&& stepTrace.plane.normal[2] >= MIN_WALK_NORMAL ) {
+				PM_Jump();
+			}
+		}
+
 		if ( pm->debugLevel ) {
 			Com_Printf("%i:stepped\n", c_pmove);
 		}

code/game/g_active.c

@@ -1034,6 +1034,12 @@ void ClientThink( int clientNum ) {
 	// phone jack if they don't get any for a while
 	ent->client->lastCmdTime = level.time;
 
+	// demo playback: don't run ClientThink_real -- cgame owns
+	// the camera movement, G_RunFrame handles buttons and PVS origin
+	if ( g_svDemoPlaying.integer ) {
+		return;
+	}
+
 	if ( !(ent->r.svFlags & SVF_BOT) && !g_synchronousClients.integer ) {
 		ClientThink_real( ent );
 	}

code/game/g_client.c

@@ -1012,6 +1012,12 @@ void ClientBegin( int clientNum ) {
 	client->pers.enterTime = level.time;
 	client->pers.teamState.state = TEAM_BEGIN;
 
+	// demo playback: force all clients to spectator
+	if ( g_svDemoPlaying.integer ) {
+		client->sess.sessionTeam = TEAM_SPECTATOR;
+		ClientUserinfoChanged( ent->client - level.clients );
+	}
+
 	// save eflags around this, because changing teams will
 	// cause this to happen with a valid entity, and we
 	// want to make sure the teleport bit is set right

code/game/g_cmds.c

@@ -661,6 +661,20 @@ void Cmd_Team_f( gentity_t *ent ) {
 	int			oldTeam;
 	char		s[MAX_TOKEN_CHARS];
 
+	// demo playback: only allow "team spectator" (to exit follow mode)
+	if ( g_svDemoPlaying.integer ) {
+		char s2[MAX_TOKEN_CHARS];
+		if ( trap_Argc() == 2 ) {
+			trap_Argv( 1, s2, sizeof(s2) );
+			if ( !Q_stricmp( s2, "spectator" ) || !Q_stricmp( s2, "s" ) ) {
+				StopFollowing( ent );
+				return;
+			}
+		}
+		trap_SendServerCommand( ent-g_entities, "print \"Only spectating allowed during demo playback.\n\"" );
+		return;
+	}
+
 	if ( trap_Argc() != 2 ) {
 		oldTeam = ent->client->sess.sessionTeam;
 		switch ( oldTeam ) {

code/game/g_local.h

@@ -641,6 +641,7 @@ void ClientCommand( int clientNum );
 // g_active.c
 //
 void ClientThink( int clientNum );
+void ClientThink_real( gentity_t *ent );
 void ClientEndFrame( gentity_t *ent );
 void G_RunClient( gentity_t *ent );
 
@@ -715,6 +716,7 @@ extern	gentity_t		g_entities[MAX_GENTITIES];
 #define	FOFS(x) ((int)&(((gentity_t *)0)->x))
 
 extern	vmCvar_t	g_gametype;
+extern	vmCvar_t	g_svDemoPlaying;
 extern	vmCvar_t	g_dedicated;
 extern	vmCvar_t	g_cheats;
 extern	vmCvar_t	g_maxclients;			// allow this many total, including spectators

code/game/g_main.c

@@ -39,6 +39,7 @@ gentity_t		g_entities[MAX_GENTITIES];
 gclient_t		g_clients[MAX_CLIENTS];
 
 vmCvar_t	g_gametype;
+vmCvar_t	g_svDemoPlaying;
 vmCvar_t	g_dmflags;
 vmCvar_t	g_fraglimit;
 vmCvar_t	g_timelimit;
@@ -108,6 +109,7 @@ static cvarTable_t		gameCvarTable[] = {
 
 	// latched vars
 	{ &g_gametype, "g_gametype", "0", CVAR_SERVERINFO | CVAR_USERINFO | CVAR_LATCH, 0, qfalse  },
+	{ &g_svDemoPlaying, "sv_demoplaying", "0", CVAR_ROM, 0, qfalse  },
 
 	{ &g_maxclients, "sv_maxclients", "8", CVAR_SERVERINFO | CVAR_LATCH | CVAR_ARCHIVE, 0, qfalse  },
 	{ &g_maxGameClients, "g_maxGameClients", "0", CVAR_SERVERINFO | CVAR_LATCH | CVAR_ARCHIVE, 0, qfalse  },
@@ -416,6 +418,11 @@ void G_InitGame( int levelTime, int randomSeed, int restart ) {
 
 	G_RegisterCvars();
 
+	// signal server-side demo mode to cgame via configstring
+	if ( g_svDemoPlaying.integer ) {
+		trap_SetConfigstring( CS_SVDEMO, "1" );
+	}
+
 	G_ProcessIPBans();
 
 	G_InitMemory();
@@ -764,6 +771,10 @@ void CalculateRanks( void ) {
 	int		rank;
 	int		score;
 	int		newScore;
+
+	// (demo playback note: this runs normally so the spectator
+	// appears in sortedClients. Recorded players won't show here
+	// since they're not connected in the game module.)
 	gclient_t	*cl;
 
 	level.follow1 = -1;
@@ -1729,6 +1740,89 @@ int start, end;
 	// get any cvar changes
 	G_UpdateCvars();
 
+	// demo playback: sync recorded player states and process spectator
+	if ( g_svDemoPlaying.integer ) {
+		gentity_t *specEnt = NULL;
+
+		// mark recorded players as connected based on their playerState.
+		// the server injected playerStates via SV_GameClientNum before
+		// calling G_RunFrame, so g_clients[i].ps is already populated.
+		for ( i = 0; i < level.maxclients; i++ ) {
+			gclient_t *cl = &level.clients[i];
+			gentity_t *e = &g_entities[i];
+
+			// find the spectator -- use client-owned origin for PVS
+			if ( e->client && cl->pers.connected == CON_CONNECTED
+				 && cl->sess.sessionTeam == TEAM_SPECTATOR ) {
+				// copy client-owned origin from usercmd for PVS culling.
+				// cgame runs its own PmoveSingle for camera movement.
+				if ( cl->pers.cmd.hasOrigin ) {
+					VectorCopy( cl->pers.cmd.origin, cl->ps.origin );
+					VectorCopy( cl->pers.cmd.origin, e->s.pos.trBase );
+					VectorCopy( cl->pers.cmd.origin, e->r.currentOrigin );
+				}
+				// process spectator buttons for follow mode switching
+				// (pers.cmd is updated by ClientThink which still runs)
+				{
+					int oldButtons = cl->buttons;
+					cl->oldbuttons = cl->buttons;
+					cl->buttons = cl->pers.cmd.buttons;
+					// attack cycles follow targets
+					if ( ( cl->buttons & BUTTON_ATTACK ) && !( oldButtons & BUTTON_ATTACK ) ) {
+						Cmd_FollowCycle_f( e, 1 );
+					}
+				}
+				specEnt = e;
+				continue;
+			}
+
+			// check if server injected a valid playerState for this slot
+			if ( cl->ps.commandTime > 0 ) {
+				cl->pers.connected = CON_CONNECTED;
+				cl->sess.sessionTeam = cl->ps.persistant[PERS_TEAM];
+				e->inuse = qtrue;
+				e->client = cl;
+				e->s.clientNum = i;
+				e->s.number = i;
+			} else if ( cl->pers.connected == CON_CONNECTED
+						&& cl->sess.sessionTeam != TEAM_SPECTATOR ) {
+				// player left -- mark disconnected
+				cl->pers.connected = CON_DISCONNECTED;
+				e->inuse = qfalse;
+			}
+		}
+
+		// evaluate trajectories and link all recorded entities for PVS.
+		// SVD_ReadFrame injected entityState_t but didn't link because
+		// the server doesn't have BG_EvaluateTrajectory.
+		// scan up to MAX_GENTITIES because recorded entities may exceed
+		// level.num_entities (which only counts game-module-spawned entities).
+		for ( i = 0; i < MAX_GENTITIES; i++ ) {
+			ent = &g_entities[i];
+			if ( ent->s.eType == 0 && !ent->inuse ) {
+				continue;
+			}
+			// skip spectator slot
+			if ( ent->client && ent->client->pers.connected == CON_CONNECTED
+				 && ent->client->sess.sessionTeam == TEAM_SPECTATOR ) {
+				continue;
+			}
+			// compute currentOrigin from trajectory
+			BG_EvaluateTrajectory( &ent->s.pos, level.time, ent->r.currentOrigin );
+			ent->r.linked = qtrue;
+			trap_LinkEntity( ent );
+		}
+
+		// update rankings so follow mode can cycle through players
+		CalculateRanks();
+
+		// run end-of-frame for spectator (handles follow mode PS copy)
+		if ( specEnt ) {
+			ClientEndFrame( specEnt );
+		}
+		return;
+	}
+
 	//
 	// go through all allocated objects
 	//

code/game/g_session.c

@@ -183,6 +183,12 @@ G_WriteSessionData
 void G_WriteSessionData( void ) {
 	int		i;
 
+	// don't persist demo spectator sessions -- the forced TEAM_SPECTATOR
+	// would carry over to the next normal game
+	if ( g_svDemoPlaying.integer ) {
+		return;
+	}
+
 	trap_Cvar_Set( "session", va("%i", g_gametype.integer) );
 
 	for ( i = 0 ; i < level.maxclients ; i++ ) {

code/game/q_shared.h

@@ -1085,6 +1085,7 @@ typedef enum {
 #define	SNAPFLAG_RATE_DELAYED	1
 #define	SNAPFLAG_NOT_ACTIVE		2	// snapshot used during connection and for zombies
 #define SNAPFLAG_SERVERCOUNT	4	// toggled every map_restart so transitions can be detected
+#define SNAPFLAG_RESET_ENTITIES	16	// snap all entities to current position, no interpolation
 
 //
 // per-level limits
@@ -1212,6 +1213,9 @@ typedef struct playerState_s {
 	int			pmove_framecount;	// FIXME: don't transmit over the network
 	int			jumppad_frame;
 	int			entityEventSequence;
+
+	// QL additions
+	int			lastJumpTime;		// serverTime of last jump, for 100ms cooldown
 } playerState_t;
 
 
@@ -1251,6 +1255,9 @@ typedef struct usercmd_s {
 	int 			buttons;
 	byte			weapon;           // weapon
 	signed char	forwardmove, rightmove, upmove;
+	// client-owned origin for demo spectator PVS (optional)
+	qboolean		hasOrigin;
+	float			origin[3];
 } usercmd_t;
 
 //===================================================================

code/qcommon/msg.c

@@ -702,8 +702,7 @@ void MSG_WriteDeltaUsercmdKey( msg_t *msg, int key, usercmd_t *from, usercmd_t *
 		from->weapon == to->weapon) {
 			MSG_WriteBits( msg, 0, 1 );				// no change
 			oldsize += 7;
-			return;
-	}
+	} else {
 		key ^= to->serverTime;
 		MSG_WriteBits( msg, 1, 1 );
 		MSG_WriteDeltaKey( msg, key, from->angles[0], to->angles[0], 16 );
@@ -714,6 +713,16 @@ void MSG_WriteDeltaUsercmdKey( msg_t *msg, int key, usercmd_t *from, usercmd_t *
 		MSG_WriteDeltaKey( msg, key, from->upmove, to->upmove, 8 );
 		MSG_WriteDeltaKey( msg, key, from->buttons, to->buttons, 16 );
 		MSG_WriteDeltaKey( msg, key, from->weapon, to->weapon, 8 );
+	}
+	// optional client-owned origin (always written, independent of field changes)
+	if ( to->hasOrigin ) {
+		MSG_WriteBits( msg, 1, 1 );
+		MSG_WriteFloat( msg, to->origin[0] );
+		MSG_WriteFloat( msg, to->origin[1] );
+		MSG_WriteFloat( msg, to->origin[2] );
+	} else {
+		MSG_WriteBits( msg, 0, 1 );
+	}
 }
 
 
@@ -748,6 +757,15 @@ void MSG_ReadDeltaUsercmdKey( msg_t *msg, int key, usercmd_t *from, usercmd_t *t
 		to->buttons = from->buttons;
 		to->weapon = from->weapon;
 	}
+	// optional client-owned origin
+	if ( MSG_ReadBits( msg, 1 ) ) {
+		to->hasOrigin = qtrue;
+		to->origin[0] = MSG_ReadFloat( msg );
+		to->origin[1] = MSG_ReadFloat( msg );
+		to->origin[2] = MSG_ReadFloat( msg );
+	} else {
+		to->hasOrigin = qfalse;
+	}
 }
 
 /*
@@ -1147,7 +1165,8 @@ netField_t	playerStateFields[] =
 { PSF(grapplePoint[1]), 0 },
 { PSF(grapplePoint[2]), 0 },
 { PSF(jumppad_ent), 10 },
-{ PSF(loopSound), 16 }
+{ PSF(loopSound), 16 },
+{ PSF(lastJumpTime), 32 }
 };
 
 /*

code/quake3.vcxproj

@@ -995,6 +995,8 @@
       <Optimization Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">MaxSpeed</Optimization>
       <Optimization Condition="'$(Configuration)|$(Platform)'=='vector|Win32'">MaxSpeed</Optimization>
     </ClCompile>
+    <ClCompile Include="server\sv_netdemo.c">
+    </ClCompile>
     <ClCompile Include="server\sv_world.c">
       <Optimization Condition="'$(Configuration)|$(Platform)'=='Debug TA DEMO|Win32'">Disabled</Optimization>
       <BrowseInformation Condition="'$(Configuration)|$(Platform)'=='Debug TA DEMO|Win32'">true</BrowseInformation>

code/server/lz4.h

@@ -0,0 +1,886 @@
+/*
+ *  LZ4 - Fast LZ compression algorithm
+ *  Header File
+ *  Copyright (c) Yann Collet. All rights reserved.
+
+   BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are
+   met:
+
+       * Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above
+   copyright notice, this list of conditions and the following disclaimer
+   in the documentation and/or other materials provided with the
+   distribution.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+   You can contact the author at :
+    - LZ4 homepage : http://www.lz4.org
+    - LZ4 source repository : https://github.com/lz4/lz4
+*/
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+#ifndef LZ4_H_2983827168210
+#define LZ4_H_2983827168210
+
+/* --- Dependency --- */
+#include <stddef.h>   /* size_t */
+
+
+/**
+  Introduction
+
+  LZ4 is lossless compression algorithm, providing compression speed >500 MB/s per core,
+  scalable with multi-cores CPU. It features an extremely fast decoder, with speed in
+  multiple GB/s per core, typically reaching RAM speed limits on multi-core systems.
+
+  The LZ4 compression library provides in-memory compression and decompression functions.
+  It gives full buffer control to user.
+  Compression can be done in:
+    - a single step (described as Simple Functions)
+    - a single step, reusing a context (described in Advanced Functions)
+    - unbounded multiple steps (described as Streaming compression)
+
+  lz4.h generates and decodes LZ4-compressed blocks (doc/lz4_Block_format.md).
+  Decompressing such a compressed block requires additional metadata.
+  Exact metadata depends on exact decompression function.
+  For the typical case of LZ4_decompress_safe(),
+  metadata includes block's compressed size, and maximum bound of decompressed size.
+  Each application is free to encode and pass such metadata in whichever way it wants.
+
+  lz4.h only handle blocks, it can not generate Frames.
+
+  Blocks are different from Frames (doc/lz4_Frame_format.md).
+  Frames bundle both blocks and metadata in a specified manner.
+  Embedding metadata is required for compressed data to be self-contained and portable.
+  Frame format is delivered through a companion API, declared in lz4frame.h.
+  The `lz4` CLI can only manage frames.
+*/
+
+/*^***************************************************************
+*  Export parameters
+*****************************************************************/
+/*
+*  LZ4_DLL_EXPORT :
+*  Enable exporting of functions when building a Windows DLL
+*  LZ4LIB_VISIBILITY :
+*  Control library symbols visibility.
+*/
+#ifndef LZ4LIB_VISIBILITY
+#  if defined(__GNUC__) && (__GNUC__ >= 4)
+#    define LZ4LIB_VISIBILITY __attribute__ ((visibility ("default")))
+#  else
+#    define LZ4LIB_VISIBILITY
+#  endif
+#endif
+#if defined(LZ4_DLL_EXPORT) && (LZ4_DLL_EXPORT==1)
+#  define LZ4LIB_API __declspec(dllexport) LZ4LIB_VISIBILITY
+#elif defined(LZ4_DLL_IMPORT) && (LZ4_DLL_IMPORT==1)
+#  define LZ4LIB_API __declspec(dllimport) LZ4LIB_VISIBILITY /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/
+#else
+#  define LZ4LIB_API LZ4LIB_VISIBILITY
+#endif
+
+/*! LZ4_FREESTANDING :
+ *  When this macro is set to 1, it enables "freestanding mode" that is
+ *  suitable for typical freestanding environment which doesn't support
+ *  standard C library.
+ *
+ *  - LZ4_FREESTANDING is a compile-time switch.
+ *  - It requires the following macros to be defined:
+ *    LZ4_memcpy, LZ4_memmove, LZ4_memset.
+ *  - It only enables LZ4/HC functions which don't use heap.
+ *    All LZ4F_* functions are not supported.
+ *  - See tests/freestanding.c to check its basic setup.
+ */
+#if defined(LZ4_FREESTANDING) && (LZ4_FREESTANDING == 1)
+#  define LZ4_HEAPMODE 0
+#  define LZ4HC_HEAPMODE 0
+#  define LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION 1
+#  if !defined(LZ4_memcpy)
+#    error "LZ4_FREESTANDING requires macro 'LZ4_memcpy'."
+#  endif
+#  if !defined(LZ4_memset)
+#    error "LZ4_FREESTANDING requires macro 'LZ4_memset'."
+#  endif
+#  if !defined(LZ4_memmove)
+#    error "LZ4_FREESTANDING requires macro 'LZ4_memmove'."
+#  endif
+#elif ! defined(LZ4_FREESTANDING)
+#  define LZ4_FREESTANDING 0
+#endif
+
+
+/*------   Version   ------*/
+#define LZ4_VERSION_MAJOR    1    /* for breaking interface changes  */
+#define LZ4_VERSION_MINOR   10    /* for new (non-breaking) interface capabilities */
+#define LZ4_VERSION_RELEASE  0    /* for tweaks, bug-fixes, or development */
+
+#define LZ4_VERSION_NUMBER (LZ4_VERSION_MAJOR *100*100 + LZ4_VERSION_MINOR *100 + LZ4_VERSION_RELEASE)
+
+#define LZ4_LIB_VERSION LZ4_VERSION_MAJOR.LZ4_VERSION_MINOR.LZ4_VERSION_RELEASE
+#define LZ4_QUOTE(str) #str
+#define LZ4_EXPAND_AND_QUOTE(str) LZ4_QUOTE(str)
+#define LZ4_VERSION_STRING LZ4_EXPAND_AND_QUOTE(LZ4_LIB_VERSION)  /* requires v1.7.3+ */
+
+LZ4LIB_API int LZ4_versionNumber (void);  /**< library version number; useful to check dll version; requires v1.3.0+ */
+LZ4LIB_API const char* LZ4_versionString (void);   /**< library version string; useful to check dll version; requires v1.7.5+ */
+
+
+/*-************************************
+*  Tuning memory usage
+**************************************/
+/*!
+ * LZ4_MEMORY_USAGE :
+ * Can be selected at compile time, by setting LZ4_MEMORY_USAGE.
+ * Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB)
+ * Increasing memory usage improves compression ratio, generally at the cost of speed.
+ * Reduced memory usage may improve speed at the cost of ratio, thanks to better cache locality.
+ * Default value is 14, for 16KB, which nicely fits into most L1 caches.
+ */
+#ifndef LZ4_MEMORY_USAGE
+# define LZ4_MEMORY_USAGE LZ4_MEMORY_USAGE_DEFAULT
+#endif
+
+/* These are absolute limits, they should not be changed by users */
+#define LZ4_MEMORY_USAGE_MIN 10
+#define LZ4_MEMORY_USAGE_DEFAULT 14
+#define LZ4_MEMORY_USAGE_MAX 20
+
+#if (LZ4_MEMORY_USAGE < LZ4_MEMORY_USAGE_MIN)
+#  error "LZ4_MEMORY_USAGE is too small !"
+#endif
+
+#if (LZ4_MEMORY_USAGE > LZ4_MEMORY_USAGE_MAX)
+#  error "LZ4_MEMORY_USAGE is too large !"
+#endif
+
+/*-************************************
+*  Simple Functions
+**************************************/
+/*! LZ4_compress_default() :
+ *  Compresses 'srcSize' bytes from buffer 'src'
+ *  into already allocated 'dst' buffer of size 'dstCapacity'.
+ *  Compression is guaranteed to succeed if 'dstCapacity' >= LZ4_compressBound(srcSize).
+ *  It also runs faster, so it's a recommended setting.
+ *  If the function cannot compress 'src' into a more limited 'dst' budget,
+ *  compression stops *immediately*, and the function result is zero.
+ *  In which case, 'dst' content is undefined (invalid).
+ *      srcSize : max supported value is LZ4_MAX_INPUT_SIZE.
+ *      dstCapacity : size of buffer 'dst' (which must be already allocated)
+ *     @return  : the number of bytes written into buffer 'dst' (necessarily <= dstCapacity)
+ *                or 0 if compression fails
+ * Note : This function is protected against buffer overflow scenarios (never writes outside 'dst' buffer, nor read outside 'source' buffer).
+ */
+LZ4LIB_API int LZ4_compress_default(const char* src, char* dst, int srcSize, int dstCapacity);
+
+/*! LZ4_decompress_safe() :
+ * @compressedSize : is the exact complete size of the compressed block.
+ * @dstCapacity : is the size of destination buffer (which must be already allocated),
+ *                presumed an upper bound of decompressed size.
+ * @return : the number of bytes decompressed into destination buffer (necessarily <= dstCapacity)
+ *           If destination buffer is not large enough, decoding will stop and output an error code (negative value).
+ *           If the source stream is detected malformed, the function will stop decoding and return a negative result.
+ * Note 1 : This function is protected against malicious data packets :
+ *          it will never writes outside 'dst' buffer, nor read outside 'source' buffer,
+ *          even if the compressed block is maliciously modified to order the decoder to do these actions.
+ *          In such case, the decoder stops immediately, and considers the compressed block malformed.
+ * Note 2 : compressedSize and dstCapacity must be provided to the function, the compressed block does not contain them.
+ *          The implementation is free to send / store / derive this information in whichever way is most beneficial.
+ *          If there is a need for a different format which bundles together both compressed data and its metadata, consider looking at lz4frame.h instead.
+ */
+LZ4LIB_API int LZ4_decompress_safe (const char* src, char* dst, int compressedSize, int dstCapacity);
+
+
+/*-************************************
+*  Advanced Functions
+**************************************/
+#define LZ4_MAX_INPUT_SIZE        0x7E000000   /* 2 113 929 216 bytes */
+#define LZ4_COMPRESSBOUND(isize)  ((unsigned)(isize) > (unsigned)LZ4_MAX_INPUT_SIZE ? 0 : (isize) + ((isize)/255) + 16)
+
+/*! LZ4_compressBound() :
+    Provides the maximum size that LZ4 compression may output in a "worst case" scenario (input data not compressible)
+    This function is primarily useful for memory allocation purposes (destination buffer size).
+    Macro LZ4_COMPRESSBOUND() is also provided for compilation-time evaluation (stack memory allocation for example).
+    Note that LZ4_compress_default() compresses faster when dstCapacity is >= LZ4_compressBound(srcSize)
+        inputSize  : max supported value is LZ4_MAX_INPUT_SIZE
+        return : maximum output size in a "worst case" scenario
+              or 0, if input size is incorrect (too large or negative)
+*/
+LZ4LIB_API int LZ4_compressBound(int inputSize);
+
+/*! LZ4_compress_fast() :
+    Same as LZ4_compress_default(), but allows selection of "acceleration" factor.
+    The larger the acceleration value, the faster the algorithm, but also the lesser the compression.
+    It's a trade-off. It can be fine tuned, with each successive value providing roughly +~3% to speed.
+    An acceleration value of "1" is the same as regular LZ4_compress_default()
+    Values <= 0 will be replaced by LZ4_ACCELERATION_DEFAULT (currently == 1, see lz4.c).
+    Values > LZ4_ACCELERATION_MAX will be replaced by LZ4_ACCELERATION_MAX (currently == 65537, see lz4.c).
+*/
+LZ4LIB_API int LZ4_compress_fast (const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
+
+
+/*! LZ4_compress_fast_extState() :
+ *  Same as LZ4_compress_fast(), using an externally allocated memory space for its state.
+ *  Use LZ4_sizeofState() to know how much memory must be allocated,
+ *  and allocate it on 8-bytes boundaries (using `malloc()` typically).
+ *  Then, provide this buffer as `void* state` to compression function.
+ */
+LZ4LIB_API int LZ4_sizeofState(void);
+LZ4LIB_API int LZ4_compress_fast_extState (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
+
+/*! LZ4_compress_destSize() :
+ *  Reverse the logic : compresses as much data as possible from 'src' buffer
+ *  into already allocated buffer 'dst', of size >= 'dstCapacity'.
+ *  This function either compresses the entire 'src' content into 'dst' if it's large enough,
+ *  or fill 'dst' buffer completely with as much data as possible from 'src'.
+ *  note: acceleration parameter is fixed to "default".
+ *
+ * *srcSizePtr : in+out parameter. Initially contains size of input.
+ *               Will be modified to indicate how many bytes where read from 'src' to fill 'dst'.
+ *               New value is necessarily <= input value.
+ * @return : Nb bytes written into 'dst' (necessarily <= dstCapacity)
+ *           or 0 if compression fails.
+ *
+ * Note : 'targetDstSize' must be >= 1, because it's the smallest valid lz4 payload.
+ *
+ * Note 2:from v1.8.2 to v1.9.1, this function had a bug (fixed in v1.9.2+):
+ *        the produced compressed content could, in rare circumstances,
+ *        require to be decompressed into a destination buffer
+ *        larger by at least 1 byte than decompressesSize.
+ *        If an application uses `LZ4_compress_destSize()`,
+ *        it's highly recommended to update liblz4 to v1.9.2 or better.
+ *        If this can't be done or ensured,
+ *        the receiving decompression function should provide
+ *        a dstCapacity which is > decompressedSize, by at least 1 byte.
+ *        See https://github.com/lz4/lz4/issues/859 for details
+ */
+LZ4LIB_API int LZ4_compress_destSize(const char* src, char* dst, int* srcSizePtr, int targetDstSize);
+
+/*! LZ4_decompress_safe_partial() :
+ *  Decompress an LZ4 compressed block, of size 'srcSize' at position 'src',
+ *  into destination buffer 'dst' of size 'dstCapacity'.
+ *  Up to 'targetOutputSize' bytes will be decoded.
+ *  The function stops decoding on reaching this objective.
+ *  This can be useful to boost performance
+ *  whenever only the beginning of a block is required.
+ *
+ * @return : the number of bytes decoded in `dst` (necessarily <= targetOutputSize)
+ *           If source stream is detected malformed, function returns a negative result.
+ *
+ *  Note 1 : @return can be < targetOutputSize, if compressed block contains less data.
+ *
+ *  Note 2 : targetOutputSize must be <= dstCapacity
+ *
+ *  Note 3 : this function effectively stops decoding on reaching targetOutputSize,
+ *           so dstCapacity is kind of redundant.
+ *           This is because in older versions of this function,
+ *           decoding operation would still write complete sequences.
+ *           Therefore, there was no guarantee that it would stop writing at exactly targetOutputSize,
+ *           it could write more bytes, though only up to dstCapacity.
+ *           Some "margin" used to be required for this operation to work properly.
+ *           Thankfully, this is no longer necessary.
+ *           The function nonetheless keeps the same signature, in an effort to preserve API compatibility.
+ *
+ *  Note 4 : If srcSize is the exact size of the block,
+ *           then targetOutputSize can be any value,
+ *           including larger than the block's decompressed size.
+ *           The function will, at most, generate block's decompressed size.
+ *
+ *  Note 5 : If srcSize is _larger_ than block's compressed size,
+ *           then targetOutputSize **MUST** be <= block's decompressed size.
+ *           Otherwise, *silent corruption will occur*.
+ */
+LZ4LIB_API int LZ4_decompress_safe_partial (const char* src, char* dst, int srcSize, int targetOutputSize, int dstCapacity);
+
+
+/*-*********************************************
+*  Streaming Compression Functions
+***********************************************/
+typedef union LZ4_stream_u LZ4_stream_t;  /* incomplete type (defined later) */
+
+/*!
+ Note about RC_INVOKED
+
+ - RC_INVOKED is predefined symbol of rc.exe (the resource compiler which is part of MSVC/Visual Studio).
+   https://docs.microsoft.com/en-us/windows/win32/menurc/predefined-macros
+
+ - Since rc.exe is a legacy compiler, it truncates long symbol (> 30 chars)
+   and reports warning "RC4011: identifier truncated".
+
+ - To eliminate the warning, we surround long preprocessor symbol with
+   "#if !defined(RC_INVOKED) ... #endif" block that means
+   "skip this block when rc.exe is trying to read it".
+*/
+#if !defined(RC_INVOKED) /* https://docs.microsoft.com/en-us/windows/win32/menurc/predefined-macros */
+#if !defined(LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION)
+LZ4LIB_API LZ4_stream_t* LZ4_createStream(void);
+LZ4LIB_API int           LZ4_freeStream (LZ4_stream_t* streamPtr);
+#endif /* !defined(LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION) */
+#endif
+
+/*! LZ4_resetStream_fast() : v1.9.0+
+ *  Use this to prepare an LZ4_stream_t for a new chain of dependent blocks
+ *  (e.g., LZ4_compress_fast_continue()).
+ *
+ *  An LZ4_stream_t must be initialized once before usage.
+ *  This is automatically done when created by LZ4_createStream().
+ *  However, should the LZ4_stream_t be simply declared on stack (for example),
+ *  it's necessary to initialize it first, using LZ4_initStream().
+ *
+ *  After init, start any new stream with LZ4_resetStream_fast().
+ *  A same LZ4_stream_t can be re-used multiple times consecutively
+ *  and compress multiple streams,
+ *  provided that it starts each new stream with LZ4_resetStream_fast().
+ *
+ *  LZ4_resetStream_fast() is much faster than LZ4_initStream(),
+ *  but is not compatible with memory regions containing garbage data.
+ *
+ *  Note: it's only useful to call LZ4_resetStream_fast()
+ *        in the context of streaming compression.
+ *        The *extState* functions perform their own resets.
+ *        Invoking LZ4_resetStream_fast() before is redundant, and even counterproductive.
+ */
+LZ4LIB_API void LZ4_resetStream_fast (LZ4_stream_t* streamPtr);
+
+/*! LZ4_loadDict() :
+ *  Use this function to reference a static dictionary into LZ4_stream_t.
+ *  The dictionary must remain available during compression.
+ *  LZ4_loadDict() triggers a reset, so any previous data will be forgotten.
+ *  The same dictionary will have to be loaded on decompression side for successful decoding.
+ *  Dictionary are useful for better compression of small data (KB range).
+ *  While LZ4 itself accepts any input as dictionary, dictionary efficiency is also a topic.
+ *  When in doubt, employ the Zstandard's Dictionary Builder.
+ *  Loading a size of 0 is allowed, and is the same as reset.
+ * @return : loaded dictionary size, in bytes (note: only the last 64 KB are loaded)
+ */
+LZ4LIB_API int LZ4_loadDict (LZ4_stream_t* streamPtr, const char* dictionary, int dictSize);
+
+/*! LZ4_loadDictSlow() : v1.10.0+
+ *  Same as LZ4_loadDict(),
+ *  but uses a bit more cpu to reference the dictionary content more thoroughly.
+ *  This is expected to slightly improve compression ratio.
+ *  The extra-cpu cost is likely worth it if the dictionary is re-used across multiple sessions.
+ * @return : loaded dictionary size, in bytes (note: only the last 64 KB are loaded)
+ */
+LZ4LIB_API int LZ4_loadDictSlow(LZ4_stream_t* streamPtr, const char* dictionary, int dictSize);
+
+/*! LZ4_attach_dictionary() : stable since v1.10.0
+ *
+ *  This allows efficient re-use of a static dictionary multiple times.
+ *
+ *  Rather than re-loading the dictionary buffer into a working context before
+ *  each compression, or copying a pre-loaded dictionary's LZ4_stream_t into a
+ *  working LZ4_stream_t, this function introduces a no-copy setup mechanism,
+ *  in which the working stream references @dictionaryStream in-place.
+ *
+ *  Several assumptions are made about the state of @dictionaryStream.
+ *  Currently, only states which have been prepared by LZ4_loadDict() or
+ *  LZ4_loadDictSlow() should be expected to work.
+ *
+ *  Alternatively, the provided @dictionaryStream may be NULL,
+ *  in which case any existing dictionary stream is unset.
+ *
+ *  If a dictionary is provided, it replaces any pre-existing stream history.
+ *  The dictionary contents are the only history that can be referenced and
+ *  logically immediately precede the data compressed in the first subsequent
+ *  compression call.
+ *
+ *  The dictionary will only remain attached to the working stream through the
+ *  first compression call, at the end of which it is cleared.
+ * @dictionaryStream stream (and source buffer) must remain in-place / accessible / unchanged
+ *  through the completion of the compression session.
+ *
+ *  Note: there is no equivalent LZ4_attach_*() method on the decompression side
+ *  because there is no initialization cost, hence no need to share the cost across multiple sessions.
+ *  To decompress LZ4 blocks using dictionary, attached or not,
+ *  just employ the regular LZ4_setStreamDecode() for streaming,
+ *  or the stateless LZ4_decompress_safe_usingDict() for one-shot decompression.
+ */
+LZ4LIB_API void
+LZ4_attach_dictionary(LZ4_stream_t* workingStream,
+                const LZ4_stream_t* dictionaryStream);
+
+/*! LZ4_compress_fast_continue() :
+ *  Compress 'src' content using data from previously compressed blocks, for better compression ratio.
+ * 'dst' buffer must be already allocated.
+ *  If dstCapacity >= LZ4_compressBound(srcSize), compression is guaranteed to succeed, and runs faster.
+ *
+ * @return : size of compressed block
+ *           or 0 if there is an error (typically, cannot fit into 'dst').
+ *
+ *  Note 1 : Each invocation to LZ4_compress_fast_continue() generates a new block.
+ *           Each block has precise boundaries.
+ *           Each block must be decompressed separately, calling LZ4_decompress_*() with relevant metadata.
+ *           It's not possible to append blocks together and expect a single invocation of LZ4_decompress_*() to decompress them together.
+ *
+ *  Note 2 : The previous 64KB of source data is __assumed__ to remain present, unmodified, at same address in memory !
+ *
+ *  Note 3 : When input is structured as a double-buffer, each buffer can have any size, including < 64 KB.
+ *           Make sure that buffers are separated, by at least one byte.
+ *           This construction ensures that each block only depends on previous block.
+ *
+ *  Note 4 : If input buffer is a ring-buffer, it can have any size, including < 64 KB.
+ *
+ *  Note 5 : After an error, the stream status is undefined (invalid), it can only be reset or freed.
+ */
+LZ4LIB_API int LZ4_compress_fast_continue (LZ4_stream_t* streamPtr, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
+
+/*! LZ4_saveDict() :
+ *  If last 64KB data cannot be guaranteed to remain available at its current memory location,
+ *  save it into a safer place (char* safeBuffer).
+ *  This is schematically equivalent to a memcpy() followed by LZ4_loadDict(),
+ *  but is much faster, because LZ4_saveDict() doesn't need to rebuild tables.
+ * @return : saved dictionary size in bytes (necessarily <= maxDictSize), or 0 if error.
+ */
+LZ4LIB_API int LZ4_saveDict (LZ4_stream_t* streamPtr, char* safeBuffer, int maxDictSize);
+
+
+/*-**********************************************
+*  Streaming Decompression Functions
+*  Bufferless synchronous API
+************************************************/
+typedef union LZ4_streamDecode_u LZ4_streamDecode_t;   /* tracking context */
+
+/*! LZ4_createStreamDecode() and LZ4_freeStreamDecode() :
+ *  creation / destruction of streaming decompression tracking context.
+ *  A tracking context can be re-used multiple times.
+ */
+#if !defined(RC_INVOKED) /* https://docs.microsoft.com/en-us/windows/win32/menurc/predefined-macros */
+#if !defined(LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION)
+LZ4LIB_API LZ4_streamDecode_t* LZ4_createStreamDecode(void);
+LZ4LIB_API int                 LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream);
+#endif /* !defined(LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION) */
+#endif
+
+/*! LZ4_setStreamDecode() :
+ *  An LZ4_streamDecode_t context can be allocated once and re-used multiple times.
+ *  Use this function to start decompression of a new stream of blocks.
+ *  A dictionary can optionally be set. Use NULL or size 0 for a reset order.
+ *  Dictionary is presumed stable : it must remain accessible and unmodified during next decompression.
+ * @return : 1 if OK, 0 if error
+ */
+LZ4LIB_API int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dictionary, int dictSize);
+
+/*! LZ4_decoderRingBufferSize() : v1.8.2+
+ *  Note : in a ring buffer scenario (optional),
+ *  blocks are presumed decompressed next to each other
+ *  up to the moment there is not enough remaining space for next block (remainingSize < maxBlockSize),
+ *  at which stage it resumes from beginning of ring buffer.
+ *  When setting such a ring buffer for streaming decompression,
+ *  provides the minimum size of this ring buffer
+ *  to be compatible with any source respecting maxBlockSize condition.
+ * @return : minimum ring buffer size,
+ *           or 0 if there is an error (invalid maxBlockSize).
+ */
+LZ4LIB_API int LZ4_decoderRingBufferSize(int maxBlockSize);
+#define LZ4_DECODER_RING_BUFFER_SIZE(maxBlockSize) (65536 + 14 + (maxBlockSize))  /* for static allocation; maxBlockSize presumed valid */
+
+/*! LZ4_decompress_safe_continue() :
+ *  This decoding function allows decompression of consecutive blocks in "streaming" mode.
+ *  The difference with the usual independent blocks is that
+ *  new blocks are allowed to find references into former blocks.
+ *  A block is an unsplittable entity, and must be presented entirely to the decompression function.
+ *  LZ4_decompress_safe_continue() only accepts one block at a time.
+ *  It's modeled after `LZ4_decompress_safe()` and behaves similarly.
+ *
+ * @LZ4_streamDecode : decompression state, tracking the position in memory of past data
+ * @compressedSize : exact complete size of one compressed block.
+ * @dstCapacity : size of destination buffer (which must be already allocated),
+ *                must be an upper bound of decompressed size.
+ * @return : number of bytes decompressed into destination buffer (necessarily <= dstCapacity)
+ *           If destination buffer is not large enough, decoding will stop and output an error code (negative value).
+ *           If the source stream is detected malformed, the function will stop decoding and return a negative result.
+ *
+ *  The last 64KB of previously decoded data *must* remain available and unmodified
+ *  at the memory position where they were previously decoded.
+ *  If less than 64KB of data has been decoded, all the data must be present.
+ *
+ *  Special : if decompression side sets a ring buffer, it must respect one of the following conditions :
+ *  - Decompression buffer size is _at least_ LZ4_decoderRingBufferSize(maxBlockSize).
+ *    maxBlockSize is the maximum size of any single block. It can have any value > 16 bytes.
+ *    In which case, encoding and decoding buffers do not need to be synchronized.
+ *    Actually, data can be produced by any source compliant with LZ4 format specification, and respecting maxBlockSize.
+ *  - Synchronized mode :
+ *    Decompression buffer size is _exactly_ the same as compression buffer size,
+ *    and follows exactly same update rule (block boundaries at same positions),
+ *    and decoding function is provided with exact decompressed size of each block (exception for last block of the stream),
+ *    _then_ decoding & encoding ring buffer can have any size, including small ones ( < 64 KB).
+ *  - Decompression buffer is larger than encoding buffer, by a minimum of maxBlockSize more bytes.
+ *    In which case, encoding and decoding buffers do not need to be synchronized,
+ *    and encoding ring buffer can have any size, including small ones ( < 64 KB).
+ *
+ *  Whenever these conditions are not possible,
+ *  save the last 64KB of decoded data into a safe buffer where it can't be modified during decompression,
+ *  then indicate where this data is saved using LZ4_setStreamDecode(), before decompressing next block.
+*/
+LZ4LIB_API int
+LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode,
+                        const char* src, char* dst,
+                        int srcSize, int dstCapacity);
+
+
+/*! LZ4_decompress_safe_usingDict() :
+ *  Works the same as
+ *  a combination of LZ4_setStreamDecode() followed by LZ4_decompress_safe_continue()
+ *  However, it's stateless: it doesn't need any LZ4_streamDecode_t state.
+ *  Dictionary is presumed stable : it must remain accessible and unmodified during decompression.
+ *  Performance tip : Decompression speed can be substantially increased
+ *                    when dst == dictStart + dictSize.
+ */
+LZ4LIB_API int
+LZ4_decompress_safe_usingDict(const char* src, char* dst,
+                              int srcSize, int dstCapacity,
+                              const char* dictStart, int dictSize);
+
+/*! LZ4_decompress_safe_partial_usingDict() :
+ *  Behaves the same as LZ4_decompress_safe_partial()
+ *  with the added ability to specify a memory segment for past data.
+ *  Performance tip : Decompression speed can be substantially increased
+ *                    when dst == dictStart + dictSize.
+ */
+LZ4LIB_API int
+LZ4_decompress_safe_partial_usingDict(const char* src, char* dst,
+                                      int compressedSize,
+                                      int targetOutputSize, int maxOutputSize,
+                                      const char* dictStart, int dictSize);
+
+#endif /* LZ4_H_2983827168210 */
+
+
+/*^*************************************
+ * !!!!!!   STATIC LINKING ONLY   !!!!!!
+ ***************************************/
+
+/*-****************************************************************************
+ * Experimental section
+ *
+ * Symbols declared in this section must be considered unstable. Their
+ * signatures or semantics may change, or they may be removed altogether in the
+ * future. They are therefore only safe to depend on when the caller is
+ * statically linked against the library.
+ *
+ * To protect against unsafe usage, not only are the declarations guarded,
+ * the definitions are hidden by default
+ * when building LZ4 as a shared/dynamic library.
+ *
+ * In order to access these declarations,
+ * define LZ4_STATIC_LINKING_ONLY in your application
+ * before including LZ4's headers.
+ *
+ * In order to make their implementations accessible dynamically, you must
+ * define LZ4_PUBLISH_STATIC_FUNCTIONS when building the LZ4 library.
+ ******************************************************************************/
+
+#ifdef LZ4_STATIC_LINKING_ONLY
+
+#ifndef LZ4_STATIC_3504398509
+#define LZ4_STATIC_3504398509
+
+#ifdef LZ4_PUBLISH_STATIC_FUNCTIONS
+# define LZ4LIB_STATIC_API LZ4LIB_API
+#else
+# define LZ4LIB_STATIC_API
+#endif
+
+
+/*! LZ4_compress_fast_extState_fastReset() :
+ *  A variant of LZ4_compress_fast_extState().
+ *
+ *  Using this variant avoids an expensive initialization step.
+ *  It is only safe to call if the state buffer is known to be correctly initialized already
+ *  (see above comment on LZ4_resetStream_fast() for a definition of "correctly initialized").
+ *  From a high level, the difference is that
+ *  this function initializes the provided state with a call to something like LZ4_resetStream_fast()
+ *  while LZ4_compress_fast_extState() starts with a call to LZ4_resetStream().
+ */
+LZ4LIB_STATIC_API int LZ4_compress_fast_extState_fastReset (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
+
+/*! LZ4_compress_destSize_extState() : introduced in v1.10.0
+ *  Same as LZ4_compress_destSize(), but using an externally allocated state.
+ *  Also: exposes @acceleration
+ */
+int LZ4_compress_destSize_extState(void* state, const char* src, char* dst, int* srcSizePtr, int targetDstSize, int acceleration);
+
+/*! In-place compression and decompression
+ *
+ * It's possible to have input and output sharing the same buffer,
+ * for highly constrained memory environments.
+ * In both cases, it requires input to lay at the end of the buffer,
+ * and decompression to start at beginning of the buffer.
+ * Buffer size must feature some margin, hence be larger than final size.
+ *
+ * |<------------------------buffer--------------------------------->|
+ *                             |<-----------compressed data--------->|
+ * |<-----------decompressed size------------------>|
+ *                                                  |<----margin---->|
+ *
+ * This technique is more useful for decompression,
+ * since decompressed size is typically larger,
+ * and margin is short.
+ *
+ * In-place decompression will work inside any buffer
+ * which size is >= LZ4_DECOMPRESS_INPLACE_BUFFER_SIZE(decompressedSize).
+ * This presumes that decompressedSize > compressedSize.
+ * Otherwise, it means compression actually expanded data,
+ * and it would be more efficient to store such data with a flag indicating it's not compressed.
+ * This can happen when data is not compressible (already compressed, or encrypted).
+ *
+ * For in-place compression, margin is larger, as it must be able to cope with both
+ * history preservation, requiring input data to remain unmodified up to LZ4_DISTANCE_MAX,
+ * and data expansion, which can happen when input is not compressible.
+ * As a consequence, buffer size requirements are much higher,
+ * and memory savings offered by in-place compression are more limited.
+ *
+ * There are ways to limit this cost for compression :
+ * - Reduce history size, by modifying LZ4_DISTANCE_MAX.
+ *   Note that it is a compile-time constant, so all compressions will apply this limit.
+ *   Lower values will reduce compression ratio, except when input_size < LZ4_DISTANCE_MAX,
+ *   so it's a reasonable trick when inputs are known to be small.
+ * - Require the compressor to deliver a "maximum compressed size".
+ *   This is the `dstCapacity` parameter in `LZ4_compress*()`.
+ *   When this size is < LZ4_COMPRESSBOUND(inputSize), then compression can fail,
+ *   in which case, the return code will be 0 (zero).
+ *   The caller must be ready for these cases to happen,
+ *   and typically design a backup scheme to send data uncompressed.
+ * The combination of both techniques can significantly reduce
+ * the amount of margin required for in-place compression.
+ *
+ * In-place compression can work in any buffer
+ * which size is >= (maxCompressedSize)
+ * with maxCompressedSize == LZ4_COMPRESSBOUND(srcSize) for guaranteed compression success.
+ * LZ4_COMPRESS_INPLACE_BUFFER_SIZE() depends on both maxCompressedSize and LZ4_DISTANCE_MAX,
+ * so it's possible to reduce memory requirements by playing with them.
+ */
+
+#define LZ4_DECOMPRESS_INPLACE_MARGIN(compressedSize)          (((compressedSize) >> 8) + 32)
+#define LZ4_DECOMPRESS_INPLACE_BUFFER_SIZE(decompressedSize)   ((decompressedSize) + LZ4_DECOMPRESS_INPLACE_MARGIN(decompressedSize))  /**< note: presumes that compressedSize < decompressedSize. note2: margin is overestimated a bit, since it could use compressedSize instead */
+
+#ifndef LZ4_DISTANCE_MAX   /* history window size; can be user-defined at compile time */
+#  define LZ4_DISTANCE_MAX 65535   /* set to maximum value by default */
+#endif
+
+#define LZ4_COMPRESS_INPLACE_MARGIN                           (LZ4_DISTANCE_MAX + 32)   /* LZ4_DISTANCE_MAX can be safely replaced by srcSize when it's smaller */
+#define LZ4_COMPRESS_INPLACE_BUFFER_SIZE(maxCompressedSize)   ((maxCompressedSize) + LZ4_COMPRESS_INPLACE_MARGIN)  /**< maxCompressedSize is generally LZ4_COMPRESSBOUND(inputSize), but can be set to any lower value, with the risk that compression can fail (return code 0(zero)) */
+
+#endif   /* LZ4_STATIC_3504398509 */
+#endif   /* LZ4_STATIC_LINKING_ONLY */
+
+
+
+#ifndef LZ4_H_98237428734687
+#define LZ4_H_98237428734687
+
+/*-************************************************************
+ *  Private Definitions
+ **************************************************************
+ * Do not use these definitions directly.
+ * They are only exposed to allow static allocation of `LZ4_stream_t` and `LZ4_streamDecode_t`.
+ * Accessing members will expose user code to API and/or ABI break in future versions of the library.
+ **************************************************************/
+#define LZ4_HASHLOG   (LZ4_MEMORY_USAGE-2)
+#define LZ4_HASHTABLESIZE (1 << LZ4_MEMORY_USAGE)
+#define LZ4_HASH_SIZE_U32 (1 << LZ4_HASHLOG)       /* required as macro for static allocation */
+
+#if defined(__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
+# include <stdint.h>
+  typedef int8_t         LZ4_i8;
+  typedef unsigned char  LZ4_byte;
+  typedef uint16_t       LZ4_u16;
+  typedef uint32_t       LZ4_u32;
+#else
+  typedef   signed char  LZ4_i8;
+  typedef unsigned char  LZ4_byte;
+  typedef unsigned short LZ4_u16;
+  typedef unsigned int   LZ4_u32;
+#endif
+
+/*! LZ4_stream_t :
+ *  Never ever use below internal definitions directly !
+ *  These definitions are not API/ABI safe, and may change in future versions.
+ *  If you need static allocation, declare or allocate an LZ4_stream_t object.
+**/
+
+typedef struct LZ4_stream_t_internal LZ4_stream_t_internal;
+struct LZ4_stream_t_internal {
+    LZ4_u32 hashTable[LZ4_HASH_SIZE_U32];
+    const LZ4_byte* dictionary;
+    const LZ4_stream_t_internal* dictCtx;
+    LZ4_u32 currentOffset;
+    LZ4_u32 tableType;
+    LZ4_u32 dictSize;
+    /* Implicit padding to ensure structure is aligned */
+};
+
+#define LZ4_STREAM_MINSIZE  ((1UL << (LZ4_MEMORY_USAGE)) + 32)  /* static size, for inter-version compatibility */
+union LZ4_stream_u {
+    char minStateSize[LZ4_STREAM_MINSIZE];
+    LZ4_stream_t_internal internal_donotuse;
+}; /* previously typedef'd to LZ4_stream_t */
+
+
+/*! LZ4_initStream() : v1.9.0+
+ *  An LZ4_stream_t structure must be initialized at least once.
+ *  This is automatically done when invoking LZ4_createStream(),
+ *  but it's not when the structure is simply declared on stack (for example).
+ *
+ *  Use LZ4_initStream() to properly initialize a newly declared LZ4_stream_t.
+ *  It can also initialize any arbitrary buffer of sufficient size,
+ *  and will @return a pointer of proper type upon initialization.
+ *
+ *  Note : initialization fails if size and alignment conditions are not respected.
+ *         In which case, the function will @return NULL.
+ *  Note2: An LZ4_stream_t structure guarantees correct alignment and size.
+ *  Note3: Before v1.9.0, use LZ4_resetStream() instead
+**/
+LZ4LIB_API LZ4_stream_t* LZ4_initStream (void* stateBuffer, size_t size);
+
+
+/*! LZ4_streamDecode_t :
+ *  Never ever use below internal definitions directly !
+ *  These definitions are not API/ABI safe, and may change in future versions.
+ *  If you need static allocation, declare or allocate an LZ4_streamDecode_t object.
+**/
+typedef struct {
+    const LZ4_byte* externalDict;
+    const LZ4_byte* prefixEnd;
+    size_t extDictSize;
+    size_t prefixSize;
+} LZ4_streamDecode_t_internal;
+
+#define LZ4_STREAMDECODE_MINSIZE 32
+union LZ4_streamDecode_u {
+    char minStateSize[LZ4_STREAMDECODE_MINSIZE];
+    LZ4_streamDecode_t_internal internal_donotuse;
+} ;   /* previously typedef'd to LZ4_streamDecode_t */
+
+
+
+/*-************************************
+*  Obsolete Functions
+**************************************/
+
+/*! Deprecation warnings
+ *
+ *  Deprecated functions make the compiler generate a warning when invoked.
+ *  This is meant to invite users to update their source code.
+ *  Should deprecation warnings be a problem, it is generally possible to disable them,
+ *  typically with -Wno-deprecated-declarations for gcc
+ *  or _CRT_SECURE_NO_WARNINGS in Visual.
+ *
+ *  Another method is to define LZ4_DISABLE_DEPRECATE_WARNINGS
+ *  before including the header file.
+ */
+#ifdef LZ4_DISABLE_DEPRECATE_WARNINGS
+#  define LZ4_DEPRECATED(message)   /* disable deprecation warnings */
+#else
+#  if defined (__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */
+#    define LZ4_DEPRECATED(message) [[deprecated(message)]]
+#  elif defined(_MSC_VER)
+#    define LZ4_DEPRECATED(message) __declspec(deprecated(message))
+#  elif defined(__clang__) || (defined(__GNUC__) && (__GNUC__ * 10 + __GNUC_MINOR__ >= 45))
+#    define LZ4_DEPRECATED(message) __attribute__((deprecated(message)))
+#  elif defined(__GNUC__) && (__GNUC__ * 10 + __GNUC_MINOR__ >= 31)
+#    define LZ4_DEPRECATED(message) __attribute__((deprecated))
+#  else
+#    pragma message("WARNING: LZ4_DEPRECATED needs custom implementation for this compiler")
+#    define LZ4_DEPRECATED(message)   /* disabled */
+#  endif
+#endif /* LZ4_DISABLE_DEPRECATE_WARNINGS */
+
+/*! Obsolete compression functions (since v1.7.3) */
+LZ4_DEPRECATED("use LZ4_compress_default() instead")       LZ4LIB_API int LZ4_compress               (const char* src, char* dest, int srcSize);
+LZ4_DEPRECATED("use LZ4_compress_default() instead")       LZ4LIB_API int LZ4_compress_limitedOutput (const char* src, char* dest, int srcSize, int maxOutputSize);
+LZ4_DEPRECATED("use LZ4_compress_fast_extState() instead") LZ4LIB_API int LZ4_compress_withState               (void* state, const char* source, char* dest, int inputSize);
+LZ4_DEPRECATED("use LZ4_compress_fast_extState() instead") LZ4LIB_API int LZ4_compress_limitedOutput_withState (void* state, const char* source, char* dest, int inputSize, int maxOutputSize);
+LZ4_DEPRECATED("use LZ4_compress_fast_continue() instead") LZ4LIB_API int LZ4_compress_continue                (LZ4_stream_t* LZ4_streamPtr, const char* source, char* dest, int inputSize);
+LZ4_DEPRECATED("use LZ4_compress_fast_continue() instead") LZ4LIB_API int LZ4_compress_limitedOutput_continue  (LZ4_stream_t* LZ4_streamPtr, const char* source, char* dest, int inputSize, int maxOutputSize);
+
+/*! Obsolete decompression functions (since v1.8.0) */
+LZ4_DEPRECATED("use LZ4_decompress_fast() instead") LZ4LIB_API int LZ4_uncompress (const char* source, char* dest, int outputSize);
+LZ4_DEPRECATED("use LZ4_decompress_safe() instead") LZ4LIB_API int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize, int maxOutputSize);
+
+/* Obsolete streaming functions (since v1.7.0)
+ * degraded functionality; do not use!
+ *
+ * In order to perform streaming compression, these functions depended on data
+ * that is no longer tracked in the state. They have been preserved as well as
+ * possible: using them will still produce a correct output. However, they don't
+ * actually retain any history between compression calls. The compression ratio
+ * achieved will therefore be no better than compressing each chunk
+ * independently.
+ */
+LZ4_DEPRECATED("Use LZ4_createStream() instead") LZ4LIB_API void* LZ4_create (char* inputBuffer);
+LZ4_DEPRECATED("Use LZ4_createStream() instead") LZ4LIB_API int   LZ4_sizeofStreamState(void);
+LZ4_DEPRECATED("Use LZ4_resetStream() instead")  LZ4LIB_API int   LZ4_resetStreamState(void* state, char* inputBuffer);
+LZ4_DEPRECATED("Use LZ4_saveDict() instead")     LZ4LIB_API char* LZ4_slideInputBuffer (void* state);
+
+/*! Obsolete streaming decoding functions (since v1.7.0) */
+LZ4_DEPRECATED("use LZ4_decompress_safe_usingDict() instead") LZ4LIB_API int LZ4_decompress_safe_withPrefix64k (const char* src, char* dst, int compressedSize, int maxDstSize);
+LZ4_DEPRECATED("use LZ4_decompress_fast_usingDict() instead") LZ4LIB_API int LZ4_decompress_fast_withPrefix64k (const char* src, char* dst, int originalSize);
+
+/*! Obsolete LZ4_decompress_fast variants (since v1.9.0) :
+ *  These functions used to be faster than LZ4_decompress_safe(),
+ *  but this is no longer the case. They are now slower.
+ *  This is because LZ4_decompress_fast() doesn't know the input size,
+ *  and therefore must progress more cautiously into the input buffer to not read beyond the end of block.
+ *  On top of that `LZ4_decompress_fast()` is not protected vs malformed or malicious inputs, making it a security liability.
+ *  As a consequence, LZ4_decompress_fast() is strongly discouraged, and deprecated.
+ *
+ *  The last remaining LZ4_decompress_fast() specificity is that
+ *  it can decompress a block without knowing its compressed size.
+ *  Such functionality can be achieved in a more secure manner
+ *  by employing LZ4_decompress_safe_partial().
+ *
+ *  Parameters:
+ *  originalSize : is the uncompressed size to regenerate.
+ *                 `dst` must be already allocated, its size must be >= 'originalSize' bytes.
+ * @return : number of bytes read from source buffer (== compressed size).
+ *           The function expects to finish at block's end exactly.
+ *           If the source stream is detected malformed, the function stops decoding and returns a negative result.
+ *  note : LZ4_decompress_fast*() requires originalSize. Thanks to this information, it never writes past the output buffer.
+ *         However, since it doesn't know its 'src' size, it may read an unknown amount of input, past input buffer bounds.
+ *         Also, since match offsets are not validated, match reads from 'src' may underflow too.
+ *         These issues never happen if input (compressed) data is correct.
+ *         But they may happen if input data is invalid (error or intentional tampering).
+ *         As a consequence, use these functions in trusted environments with trusted data **only**.
+ */
+LZ4_DEPRECATED("This function is deprecated and unsafe. Consider using LZ4_decompress_safe_partial() instead")
+LZ4LIB_API int LZ4_decompress_fast (const char* src, char* dst, int originalSize);
+LZ4_DEPRECATED("This function is deprecated and unsafe. Consider migrating towards LZ4_decompress_safe_continue() instead. "
+               "Note that the contract will change (requires block's compressed size, instead of decompressed size)")
+LZ4LIB_API int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* src, char* dst, int originalSize);
+LZ4_DEPRECATED("This function is deprecated and unsafe. Consider using LZ4_decompress_safe_partial_usingDict() instead")
+LZ4LIB_API int LZ4_decompress_fast_usingDict (const char* src, char* dst, int originalSize, const char* dictStart, int dictSize);
+
+/*! LZ4_resetStream() :
+ *  An LZ4_stream_t structure must be initialized at least once.
+ *  This is done with LZ4_initStream(), or LZ4_resetStream().
+ *  Consider switching to LZ4_initStream(),
+ *  invoking LZ4_resetStream() will trigger deprecation warnings in the future.
+ */
+LZ4LIB_API void LZ4_resetStream (LZ4_stream_t* streamPtr);
+
+
+#endif /* LZ4_H_98237428734687 */
+
+
+#if defined (__cplusplus)
+}
+#endif

code/server/server.h

@@ -341,6 +341,29 @@ int			SV_BotGetConsoleMessage( int client, char *buf, int size );
 int BotImport_DebugPolygonCreate(int color, int numPoints, vec3_t *points);
 void BotImport_DebugPolygonDelete(int id);
 
+//
+// sv_netdemo.c
+//
+void		SVD_Record_f( void );
+void		SVD_StopRecord_f( void );
+void		SVD_RecordFrame( void );
+void		SVD_ResetDeltaState( void );
+void		SVD_AutoRecord( void );
+void		SVD_CaptureServerCommand( const char *cmd );
+void		SVD_Play_f( void );
+void		SVD_StopPlay_f( void );
+void		SVD_CleanupPlayback( void );
+void		SVD_Stop_f( void );
+void		SVD_Pause_f( void );
+void		SVD_Seek_f( void );
+void		SVD_SeekExact_f( void );
+qboolean	SVD_PlaybackFrame( void );
+qboolean	SVD_IsRecording( void );
+qboolean	SVD_IsPlaying( void );
+qboolean	SVD_IsPaused( void );
+qboolean	SVD_IsStarting( void );
+qboolean	SVD_ShouldPause( void );
+
 //============================================================
 //
 // high level object sorting to reduce interaction tests

code/server/sv_ccmds.c

@@ -280,6 +280,9 @@ static void SV_MapRestart_f( void ) {
 	sv.state = SS_GAME;
 	sv.restarting = qfalse;
 
+	// reset demo delta state so next frame writes full entities
+	SVD_ResetDeltaState();
+
 	// connect and begin all the clients
 	for (i=0 ; i<sv_maxclients->integer ; i++) {
 		client = &svs.clients[i];
@@ -736,6 +739,14 @@ void SV_AddOperatorCommands( void ) {
 	if( com_dedicated->integer ) {
 		Cmd_AddCommand ("say", SV_ConSay_f);
 	}
+
+	// server-side demo recording/playback
+	Cmd_AddCommand ("svdemo_record", SVD_Record_f);
+	Cmd_AddCommand ("svdemo_stop", SVD_Stop_f);
+	Cmd_AddCommand ("svdemo_play", SVD_Play_f);
+	Cmd_AddCommand ("svdemo_pause", SVD_Pause_f);
+	Cmd_AddCommand ("svdemo_seek", SVD_Seek_f);
+	Cmd_AddCommand ("svdemo_seekexact", SVD_SeekExact_f);
 }
 
 /*

code/server/sv_client.c

@@ -1419,8 +1419,13 @@ static void SV_UserMove( client_t *cl, msg_t *msg, qboolean delta ) {
 		// don't execute if this is an old cmd which is already executed
 		// these old cmds are included when cl_packetdup > 0
 		if ( cmds[i].serverTime <= cl->lastUsercmd.serverTime ) {
+			// demo playback: still process the LAST cmd even with duplicate
+			// serverTime (paused = frozen time, all cmds have same time).
+			// Need buttons and origin from fresh usercmds.
+			if ( !SVD_IsPlaying() || i != cmdCount - 1 ) {
 				continue;
 			}
+		}
 		SV_ClientThink (cl, &cmds[ i ]);
 	}
 }

code/server/sv_game.c

@@ -83,6 +83,13 @@ Sends a command string to a client
 ===============
 */
 void SV_GameSendServerCommand( int clientNum, const char *text ) {
+	// capture for demo recording: broadcasts and per-client chat/tchat
+	if ( clientNum == -1 ) {
+		SVD_CaptureServerCommand( text );
+	} else if ( !strncmp( text, "chat", 4 ) || !strncmp( text, "tchat", 5 ) ) {
+		SVD_CaptureServerCommand( text );
+	}
+
 	if ( clientNum == -1 ) {
 		SV_SendServerCommand( NULL, "%s", text );
 	} else {

code/server/sv_init.c

@@ -351,6 +351,18 @@ void SV_SpawnServer( char *server, qboolean killBots ) {
 	char		systemInfo[16384];
 	const char	*p;
 
+	// stop any active demo recording/playback (one demo = one map).
+	// SVD_IsStarting() returns true when SVD_Play_f is calling devmap
+	// internally -- don't stop our own playback.
+	if ( SVD_IsRecording() ) {
+		Com_Printf( "Map change -- stopping demo recording.\n" );
+		SVD_StopRecord_f();
+	}
+	if ( SVD_IsPlaying() && !SVD_IsStarting() ) {
+		Com_Printf( "Map change -- stopping demo playback.\n" );
+		SVD_CleanupPlayback();
+	}
+
 	// shut down the existing game if it is running
 	SV_ShutdownGameProgs();
 
@@ -546,6 +558,9 @@ void SV_SpawnServer( char *server, qboolean killBots ) {
 	Hunk_SetMark();
 
 	Com_Printf ("-----------------------------------\n");
+
+	// auto-record demo if enabled
+	SVD_AutoRecord();
 }
 
 /*
@@ -612,6 +627,11 @@ void SV_Init (void) {
 	sv_lanForceRate = Cvar_Get ("sv_lanForceRate", "1", CVAR_ARCHIVE );
 	sv_strictAuth = Cvar_Get ("sv_strictAuth", "1", CVAR_ARCHIVE );
 
+	// server-side demo settings
+	Cvar_Get ("svdemo_autorecord", "0", CVAR_ARCHIVE);
+	Cvar_Get ("svdemo_pauseEmpty", "1", CVAR_ARCHIVE);
+	Cvar_Get ("svdemo_keyframeInterval", "5", CVAR_ARCHIVE);  // seconds, 0 = disabled
+
 	// initialize bot cvars so they are listed and can be set before loading the botlib
 	SV_BotInitCvars();
 
@@ -667,6 +687,15 @@ void SV_Shutdown( char *finalmsg ) {
 
 	Com_Printf( "----- Server Shutdown -----\n" );
 
+	// clean up any active demo recording/playback.
+	// skip if SVD_Play_f is calling SV_Shutdown internally.
+	if ( SVD_IsRecording() ) {
+		SVD_StopRecord_f();
+	}
+	if ( SVD_IsPlaying() && !SVD_IsStarting() ) {
+		SVD_CleanupPlayback();
+	}
+
 	if ( svs.clients && !com_errorEntered ) {
 		SV_FinalMessage( finalmsg );
 	}

code/server/sv_main.c

@@ -831,18 +831,38 @@ void SV_Frame( int msec ) {
 	// run the game simulation in chunks
 	while ( sv.timeResidual >= frameMsec ) {
 		sv.timeResidual -= frameMsec;
+
+		if ( SVD_IsPaused() ) {
+			// demo paused: freeze svs.time so trajectories freeze
+			// and client doesn't see time jumps on unpause.
+			// still run game frame for spectator movement (at frozen time).
+			VM_Call( gvm, GAME_RUN_FRAME, svs.time );
+			continue;
+		}
+
 		svs.time += frameMsec;
 
+		if ( SVD_IsPlaying() ) {
+			// demo playback: read recorded entities instead of running game logic
+			SVD_PlaybackFrame();
+			// still call the game frame for spectator movement
+		}
+
 		// let everything in the world think and move
 		VM_Call( gvm, GAME_RUN_FRAME, svs.time );
+
+		// capture frame for demo recording
+		SVD_RecordFrame();
 	}
 
 	if ( com_speeds->integer ) {
 		time_game = Sys_Milliseconds () - startTime;
 	}
 
-	// check timeouts
+	// check timeouts (skip during demo playback -- zombie slots would be freed)
+	if ( !SVD_IsPlaying() ) {
 		SV_CheckTimeouts();
+	}
 
 	// send messages back to the clients
 	SV_SendClientMessages();

code/win32/win_input.c

@@ -343,13 +343,20 @@ void IN_DIMouse( int *mx, int *my ) {
 	DIMOUSESTATE2		state;
 	DWORD				dwElements;
 	HRESULT				hr;
-	int					value;
+	int					i, value;
+	static BYTE			oldButtons[8];
+
+	static const int buttonKeys[5] = {
+		K_MOUSE1, K_MOUSE2, K_MOUSE3, K_MOUSE4, K_MOUSE5
+	};
 
 	if ( !g_pMouse ) {
 		return;
 	}
 
-	// fetch new events
+	// flush the buffered data — we only use it for wheel events.
+	// buttons are handled via immediate state below to avoid
+	// stuck keys from buffer overflow.
 	for (;;)
 	{
 		dwElements = 1;
@@ -361,51 +368,11 @@ void IN_DIMouse( int *mx, int *my ) {
 			return;
 		}
 
-		/* Unable to read data or no data available */
-		if ( FAILED(hr) ) {
-			break;
-		}
-
-		if ( dwElements == 0 ) {
+		if ( FAILED(hr) || dwElements == 0 ) {
 			break;
 		}
 
 		switch (od.dwOfs) {
-		case DIMOFS_BUTTON0:
-			if (od.dwData & 0x80)
-				Sys_QueEvent( od.dwTimeStamp, SE_KEY, K_MOUSE1, qtrue, 0, NULL );
-			else
-				Sys_QueEvent( od.dwTimeStamp, SE_KEY, K_MOUSE1, qfalse, 0, NULL );
-			break;
-
-		case DIMOFS_BUTTON1:
-			if (od.dwData & 0x80)
-				Sys_QueEvent( od.dwTimeStamp, SE_KEY, K_MOUSE2, qtrue, 0, NULL );
-			else
-				Sys_QueEvent( od.dwTimeStamp, SE_KEY, K_MOUSE2, qfalse, 0, NULL );
-			break;
-
-		case DIMOFS_BUTTON2:
-			if (od.dwData & 0x80)
-				Sys_QueEvent( od.dwTimeStamp, SE_KEY, K_MOUSE3, qtrue, 0, NULL );
-			else
-				Sys_QueEvent( od.dwTimeStamp, SE_KEY, K_MOUSE3, qfalse, 0, NULL );
-			break;
-
-		case DIMOFS_BUTTON3:
-			if (od.dwData & 0x80)
-				Sys_QueEvent( od.dwTimeStamp, SE_KEY, K_MOUSE4, qtrue, 0, NULL );
-			else
-				Sys_QueEvent( od.dwTimeStamp, SE_KEY, K_MOUSE4, qfalse, 0, NULL );
-			break;
-
-		case DIMOFS_BUTTON4:
-			if (od.dwData & 0x80)
-				Sys_QueEvent( od.dwTimeStamp, SE_KEY, K_MOUSE5, qtrue, 0, NULL );
-			else
-				Sys_QueEvent( od.dwTimeStamp, SE_KEY, K_MOUSE5, qfalse, 0, NULL );
-			break;
-
 		case DIMOFS_Z:
 			value = od.dwData;
 			if (value < 0) {
@@ -419,16 +386,29 @@ void IN_DIMouse( int *mx, int *my ) {
 		}
 	}
 
-	// read the raw delta counter and ignore
-	// the individual sample time / values
+	// read immediate device state for axes and buttons
 	hr = IDirectInputDevice8_GetDeviceState(g_pMouse,
 			sizeof(DIMOUSESTATE2), &state);
 	if ( FAILED(hr) ) {
 		*mx = *my = 0;
 		return;
 	}
+
 	*mx = state.lX;
 	*my = state.lY;
+
+	// generate button press/release events from immediate state.
+	// comparing against previous state avoids stuck buttons entirely —
+	// if a press or release was missed in the buffer, the immediate
+	// state catches it next frame.
+	for ( i = 0; i < 5; i++ ) {
+		BYTE down = state.rgbButtons[i] & 0x80;
+		if ( down != oldButtons[i] ) {
+			Sys_QueEvent( g_wv.sysMsgTime, SE_KEY, buttonKeys[i],
+						  down ? qtrue : qfalse, 0, NULL );
+			oldButtons[i] = down;
+		}
+	}
 }
 
 /*

svdemo.txt

@@ -0,0 +1,196 @@
+===========================================================================
+                    Серверные демо-записи (SVDEMO)
+                         Руководство пользователя
+===========================================================================
+
+ОПИСАНИЕ
+--------
+
+Система серверных демо-записей позволяет записывать полное состояние
+игрового сервера (все сущности, все игроки) и воспроизводить запись
+с возможностью свободного перемещения камеры или просмотра от первого
+лица любого игрока.
+
+В отличие от обычных клиентских демо (запись только того, что видит
+один игрок), серверная запись содержит полную картину матча.
+
+
+КОНСОЛЬНЫЕ КОМАНДЫ
+------------------
+
+Запись:
+
+  svdemo_record <имя>
+      Начать запись серверного демо. Файл сохраняется в
+      svdemos/<имя>.svdm внутри игровой директории.
+
+  svdemo_stop
+      Остановить текущую запись или воспроизведение.
+      При остановке воспроизведения происходит отключение от сервера.
+
+Воспроизведение:
+
+  svdemo_play <имя>
+      Воспроизвести серверное демо. Загружает карту из записи,
+      подключает зрителя автоматически. Можно вызывать из меню,
+      из игры или во время просмотра другого демо.
+
+  svdemo_pause
+      Пауза / продолжение воспроизведения. Во время паузы камера
+      свободно перемещается, сущности заморожены.
+      На экране отображается "Playback Paused".
+
+  svdemo_seek <секунды>
+      Перемотка относительно текущей позиции. Положительное значение --
+      вперёд, отрицательное -- назад.
+      Перемещает к ближайшему ключевому кадру (точность ±5 сек).
+      Работает в паузе.
+      Пример: svdemo_seek -10  (назад на 10 секунд)
+
+  svdemo_seekexact <секунды>
+      Точная перемотка. Находит ближайший ключевой кадр, затем
+      прочитывает кадры до целевого времени. Точность до одного
+      серверного кадра (50 мс при sv_fps 20). Может занять долю
+      секунды на длинных перемотках. Работает в паузе.
+      Пример: svdemo_seekexact -10  (назад ровно на 10 секунд)
+
+
+НАСТРОЙКИ (CVARS)
+-----------------
+
+  svdemo_autorecord <0|1>    (по умолчанию: 0)
+      Автоматическая запись демо при каждой загрузке карты.
+      Файлы именуются автоматически: <карта>_ГГГГММДД_ЧЧММСС.svdm
+      Пример: q3dm6_20260323_141530.svdm
+
+  svdemo_pauseEmpty <0|1>    (по умолчанию: 1)
+      Пауза воспроизведения, когда нет подключённых зрителей.
+      Демо начинается с первого кадра при подключении зрителя.
+
+  svdemo_keyframeInterval <секунды>  (по умолчанию: 5, 0 = выкл.)
+      Интервал ключевых кадров. Ключевые кадры позволяют перематывать
+      запись. Чем меньше интервал, тем точнее перемотка командой
+      svdemo_seek, но немного больше размер файла. Первый кадр
+      записи всегда является ключевым.
+
+  Все настройки сохраняются в конфигурации (CVAR_ARCHIVE).
+
+
+ЗАПИСЬ
+------
+
+1. Запустите сервер и начните игру как обычно:
+       devmap q3dm6
+
+2. Начните запись:
+       svdemo_record mymatch
+
+3. Играйте. Все действия всех игроков записываются.
+
+4. Остановите запись:
+       svdemo_stop
+
+   Запись также автоматически останавливается при:
+   - Смене карты (map, devmap, nextmap по таймлимиту/фраглимиту)
+   - Выключении сервера
+   Перезапуск карты (map_restart) НЕ прерывает запись.
+
+
+ВОСПРОИЗВЕДЕНИЕ
+---------------
+
+1. Запустите воспроизведение:
+       svdemo_play mymatch
+
+2. Карта загрузится автоматически. Вы подключитесь как зритель
+   со свободной камерой (полёт по карте).
+
+3. Управление зрителем:
+   - Свободная камера: перемещайтесь как обычный спектатор
+   - Следование за игроком: нажмите MOUSE1 (ATTACK) для входа
+     в режим следования и переключения между игроками
+   - Выход из следования: team spectator (можно забиндить)
+
+4. В режиме следования вы видите игру от первого лица выбранного
+   игрока с полным HUD: здоровье, броня, боеприпасы, оружие.
+
+5. Табло (TAB) показывает счёт записанных игроков.
+
+6. Управление воспроизведением:
+   - svdemo_pause      -- пауза/продолжение
+   - svdemo_seek -10   -- быстрая перемотка назад на 10 сек
+   - svdemo_seek 30    -- быстрая перемотка вперёд на 30 сек
+   - svdemo_seekexact -10  -- точная перемотка назад на 10 сек
+   - svdemo_stop       -- остановка и выход
+
+7. Воспроизведение останавливается автоматически при
+   достижении конца записи.
+
+
+ФОРМАТ ФАЙЛА
+-------------
+
+Расширение: .svdm
+Директория: svdemos/
+
+Файл содержит:
+- Заголовок: название карты, настройки сервера, конфигстроки
+  (имена игроков, модели, настройки игры)
+- Покадровые данные: дельта-сжатые состояния сущностей и игроков,
+  серверные команды (чат, принты), изменения конфигстрок
+- Ключевые кадры с индексом в конце файла
+
+Дельта-кодирование обеспечивает компактный размер файла.
+Типичный 10-минутный матч с 10 ботами занимает ~8 МБ.
+
+Одна запись = одна карта. При смене карты запись останавливается.
+
+
+ОГРАНИЧЕНИЯ
+-----------
+
+- Если в записанной игре было 64 игрока (MAX_CLIENTS), один
+  из них не будет виден при воспроизведении (его слот занят зрителем).
+- Воспроизведение требует наличия тех же pk3-файлов (карты, модели),
+  что использовались при записи.
+- Демо несовместимы между разными версиями движка, если изменился
+  формат сетевых структур.
+- При перемотке могут кратковременно отображаться визуальные артефакты
+  (частицы, вспышки) от локальных эффектов.
+
+
+ПРИМЕРЫ ИСПОЛЬЗОВАНИЯ
+---------------------
+
+Автоматическая запись всех матчей:
+
+    set svdemo_autorecord 1
+    devmap q3dm17
+
+    (все матчи на этом сервере будут записываться автоматически)
+
+
+Запись конкретного матча:
+
+    devmap q3tourney2
+    svdemo_record duel_finals
+    (играть...)
+    svdemo_stop
+
+
+Просмотр записи:
+
+    svdemo_play duel_finals
+
+
+Просмотр с перемоткой:
+
+    svdemo_play duel_finals
+    (подождать 30 секунд)
+    svdemo_seekexact -20   (вернуться на 20 секунд назад)
+    svdemo_pause           (поставить на паузу)
+    svdemo_seek -5         (ещё назад на 5 секунд, в паузе)
+    svdemo_pause           (продолжить)
+
+
+===========================================================================