Scenes.image

scenes.image is a binary data blob from which since (i.e. Orange Box engine) loads choreography scenes. It was created to improve performance on consoles: it is loaded into memory in its entirety when the engine starts, which eliminates the need for consoles' slow optical media to seek around on a disk for hundreds of loose .VCD files. It helps on PC too however, so has been ported across.

Important:Since , scenes can only be used from scenes.image (not in ), but scenes.image cannot be packed in BSPs, which means that workshop maps cannot use custom scenes.

Workaround:In Portal 2, the VScript function LoadSceneFromString can circumvent this limitation, for the cost of large file sizes.

Code Fix:Functions related to loading scenes can be modified in order to bypass scenes.image

Format

scenes.image files are little-endian on all platforms, with all offsets being absolute to the beginning.

Header

The scenes.image file has the following header:

Type	Meaning	Description
UInt32	ID	4-byte identified used for file identification. Always big-endian "VSIF".
UInt32	Version	scenes.image file version. 2 is used.
UInt32	Scenes number	Total number of scene files.
UInt32	Strings number	Number of strings in the string pool (explained later).
UInt32	Scene entry offset	Offset to the scene entries (explained later).

String pool

After the header, there are offsets to strings in the string pool.

The string pool stores all strings used in binary VCD (BVCD) files. BVCDs use signed 16-bit integers for string indices, so there cannot be more than 32767 strings in an image.

All strings in the pool are null-terminated.

Scene entries

The scene entries are placed at "Scene entry offset", and have the following structure:

Type	Meaning	Description
UInt32	CRC file name	CRC32 hash of scene file name (for example: scenes\???.vcd). All file names are lower-case and have \ as path separator. Valve CRC code should be used for best compatibility.
UInt32	Data offset	Offset to the scene file.
UInt32	Data length	Size of the scene file as stored in scenes.image (not real size of BVCD and/or LZMA compressed/uncompressed data).
UInt32	Scene summary offset	Offset to the scene summary (explained later).

Scene data

Scenes are stored in either uncompressed or compressed format at the offsets specified in the scene entries.

Uncompressed scenes start with "bvcd" 4-byte ID. Their size is specified in the scene entries.

Compressed scenes have the following header:

Type	Meaning	Description
UInt32	ID	Always "LZMA".
UInt32	Actual size	Size of uncompressed data.
UInt32	LZMA size	Size of compressed data.
Byte[5]	Properties	Metadata used internally by LZMA module for uncompressing.

After the header, there is compressed data, with the size being specified in the "LZMA size" field of the header.

Scenes are stored in Binary VCD format, and must be decompiled (either using CChoreoScene::RestoreFromBinaryBuffer and CChoreoScene::SaveToFile functions or a tool such as VSIF2VCD) in order to be viewable in Faceposer.

Scene summary

Scene summary stores scene information used to optimize scene playback.

Scene summaries have the following header:

Type	Meaning	Description
UInt32	Milliseconds	Scene playback length, in milliseconds.
UInt32	Sounds number	Number of sounds used in the scene.

After the header, there are 32-bit indices of strings in the string pool. The strings are sound names. They are used for precaching the scene.

To build a scenes.image, load Faceposer and choose File > Rebuild scenes.image...

This will collect all .vcd files located in your game directory's scenes folder and compile them to scenes/scenes.image, overwriting the file if it already exists. The raw .vcd files do not need to be present for a compiled scenes.image to work in-game. Image rebuilding gathers scenes in all directories, meaning scenes in a separate path (i.e. any path in gameinfo.txt that isn't the main directory ^[confirm]) will be built into scenes.image.

Warning:Only the VCD files in the game directory's scenes/ folder will be built into the image and it will completely overwrite the existing image, meaning any scenes in the image but not the rebuild would be lost. The raw .vcd files are no longer available in the current versions of most Valve titles. For Half-Life 2, this means that you will need to extract Valve's scenes for Half-Life 2, its episodes, and Lost Coast from Source SDK 2013's sp/game folders.

Bug:The file system used to gather VCDs for recompiling scenes.image doesn't seem to react well when a /* token is in gameinfo.txt's search paths (e.g. |gameinfo_path|custom/*), using that as a central game folder and not compiling any of the other directories. This bug is not well understood, but you can work around it by either compiling your scenes in a new scenes folder in the /* directory (e.g. custom/scenes) or temporarily removing said paths from your gameinfo.txt.

Bypassing

Warning:The code provided below has been documented to cause occasional crashes, seemingly due to memory corruption. Use at your own risk.

If you are producing your own binaries, the old method of loading loose files can be reinstated. The following code is based off of existing methods that can be found in the Source SDK. When you find them, copy and paste the code present here. You can paste the whole modified function or measure the differences yourself.

Note that this code attempts to load loose files before searching the image cache, which can be changed.

CChoreoScene *CSceneEntity::LoadScene( const char *filename, IChoreoEventCallback *pCallback )
{
	char loadfile[MAX_PATH];
	Q_strncpy( loadfile, filename, sizeof( loadfile ) );
	Q_SetExtension( loadfile, ".vcd", sizeof( loadfile ) );
	Q_FixSlashes( loadfile );
	
	void *pBuffer = 0;
	CChoreoScene *pScene;

	int fileSize = filesystem->ReadFileEx( loadfile, "GAME", &pBuffer, true );
	if (fileSize)
	{
		g_TokenProcessor.SetBuffer((char*)pBuffer);
		pScene = ChoreoLoadScene( loadfile, NULL, &g_TokenProcessor, LocalScene_Printf );
	}
	else
	{
		// binary compiled vcd
		pScene = new CChoreoScene( NULL );
		if ( !CopySceneFileIntoMemory( loadfile, &pBuffer, &fileSize ) )
		{
			MissingSceneWarning( loadfile );
			return NULL;
		}
		CUtlBuffer buf( pBuffer, fileSize, CUtlBuffer::READ_ONLY );
		if ( !pScene->RestoreFromBinaryBuffer( buf, loadfile, &g_ChoreoStringPool ) )
		{
			Warning( "CSceneEntity::LoadScene: Unable to load scene '%s'\n", loadfile );
			delete pScene;
			pScene = NULL;
		}
	}
	
	if(pScene)
	{
		pScene->SetPrintFunc( LocalScene_Printf );
		pScene->SetEventCallbackInterface( pCallback );
	}

	FreeSceneFileMemory( pBuffer );
	return pScene;
}

CChoreoScene *C_SceneEntity::LoadScene( const char *filename )
{
	char loadfile[MAX_PATH];
	Q_strncpy( loadfile, filename, sizeof( loadfile ) );
	Q_SetExtension( loadfile, ".vcd", sizeof( loadfile ) );
	Q_FixSlashes( loadfile );

	void *pBuffer = 0;
	CChoreoScene *pScene;

	int fileSize = filesystem->ReadFileEx( loadfile, "GAME", &pBuffer, true );
	if (fileSize)
	{
		g_TokenProcessor.SetBuffer((char*)pBuffer);
		pScene = ChoreoLoadScene( loadfile, this, &g_TokenProcessor, Scene_Printf );
	}
	else
	{
		fileSize = scenefilecache->GetSceneBufferSize( loadfile );
		if ( fileSize <= 0 )
			return NULL;

		pBuffer = new char[ fileSize ];
		if ( !scenefilecache->GetSceneData( filename, (byte *)pBuffer, fileSize ) )
		{
			delete[] pBuffer;
			return NULL;
		}

	
		if ( IsBufferBinaryVCD( (char*)pBuffer, fileSize ) )
		{
			pScene = new CChoreoScene( this );
			CUtlBuffer buf( pBuffer, fileSize, CUtlBuffer::READ_ONLY );
			if ( !pScene->RestoreFromBinaryBuffer( buf, loadfile, &g_ChoreoStringPool ) )
			{
				Warning( "Unable to restore scene '%s'\n", loadfile );
				delete pScene;
				pScene = NULL;
			}
		}
	}

	if(pScene)
	{
		pScene->SetPrintFunc( Scene_Printf );
		pScene->SetEventCallbackInterface( this );
	}

	delete[] pBuffer;
	return pScene;
}

void PrecacheInstancedScene( char const *pszScene )
{
	static int nMakingReslists = -1;
	
	if ( nMakingReslists == -1 )
	{
		nMakingReslists = CommandLine()->FindParm( "-makereslists" ) > 0 ? 1 : 0;
	}

	if ( nMakingReslists == 1 )
	{
		// Just stat the file to add to reslist
		g_pFullFileSystem->Size( pszScene );
	}

	SceneCachedData_t sceneData;

	char loadfile[MAX_PATH];
	Q_strncpy( loadfile, pszScene, sizeof( loadfile ) );
	Q_SetExtension( loadfile, ".vcd", sizeof( loadfile ) );
	Q_FixSlashes( loadfile );

	// Attempt to precache manually
	void *pBuffer = NULL;
	if (filesystem->ReadFileEx( loadfile, "GAME", &pBuffer, false, true ))
	{
		g_TokenProcessor.SetBuffer((char*)pBuffer);
		CChoreoScene *pScene = ChoreoLoadScene( loadfile, NULL, &g_TokenProcessor, LocalScene_Printf );
		if (pScene)
		{
			for ( int i = 0; i < pScene->GetNumEvents(); i++ )
			{
				CChoreoEvent *pEvent = pScene->GetEvent(i);
				if (pEvent && pEvent->GetType() == CChoreoEvent::SPEAK)
				{
					CBaseEntity::PrecacheScriptSound( pEvent->GetParameters() );

					// Precache CC token
					if ( pEvent->GetCloseCaptionType() == CChoreoEvent::CC_MASTER && 
						 pEvent->GetNumSlaves() > 0 )
					{
						char tok[ CChoreoEvent::MAX_CCTOKEN_STRING ];
						if ( pEvent->GetPlaybackCloseCaptionToken( tok, sizeof( tok ) ) )
						{
							CBaseEntity::PrecacheScriptSound( tok );
						}
					}
				}
			}
		}
	}
	else if ( !scenefilecache->GetSceneCachedData( pszScene, &sceneData ) )
	{
		// This warning was meant for when scenes.image was supposed to be the sole method of loading scenes.
		// It's been deactivated as part of the raw file support, as even if this was somehow on the Xbox 360,
		// it would never trip anyway because if the file existed, it would've been read earlier.
		//if ( developer.GetInt() && ( IsX360() && ( g_pFullFileSystem->GetDVDMode() != DVDMODE_STRICT ) && g_pFullFileSystem->FileExists( pszScene, "GAME" ) ) )
		//{
		//	Warning( "PrecacheInstancedScene: Missing scene '%s' from scene image cache.\nRebuild scene image cache!\n", pszScene );
		//}
	}
	else
	{
		for ( int i = 0; i < sceneData.numSounds; ++i )
		{
			short stringId = scenefilecache->GetSceneCachedSound( sceneData.sceneId, i );
			CBaseEntity::PrecacheScriptSound( scenefilecache->GetSceneString( stringId ) );
		}
	}

	g_pStringTableClientSideChoreoScenes->AddString( CBaseEntity::IsServer(), pszScene );
}

This code also fixes a bug where the maximum path length for a scene was longer on the server than on the client.

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