.TH "GPAC" 1 "December 2006" "GPAC Configuration" "GPAC Configuration"..SH NAME.LPGPAC	\- MPEG-4 Systems Framework and Software Development Kit.SH "DESCRIPTION".LPGPAC stands (does it ?) for GPAC Project on Advanced Content. It is an implementation of the MPEG-4 Systems standard written in ANSI C. GPAC provides tools for media playback, vector graphics and 3D rendering, MPEG-4 authoring and distribution.This man page is about configuration of the GPAC framework version 0.4.4...SH INTRODUCTIONSome applications in the GPAC framework use a configuration file shared among modules and reloadable at run time. This file is located in the user home directory and called ".gpacrc"..LPThe configuration file is based on the win32 .ini file model, ordered by sections and keys..LP A section is declared as .B [SectionName], a key is declared as.B keyName=value, the key value is not interpreted and always handled as ASCII text. Plugins may use the configuration file as well (to avoid multiple files)..LP.B Note on plugin names: Plugin names as given in the configuration file are names exported by each interface and not name of the physical library file (.dll/.so ...).The physical file name can however be used to identify a plugin, it will be replaced by the interface name if the plugin was successfully loaded....SH SECTION "General".LPThe "General" section holds generic, OS and player specific options. This section is not used by the GPAC Framework...TP.B ModulesDirectory (value: path)path to modules (plugins) location. The client cannot be loaded without modules. This option is used by all GPAC clients on all platforms.TP.B CacheDirectory (value: path)specifies location of temp files. This must be the absolute path to a directory with write access. Although not used by applications, this is used by several plugins..LPThe following options are defined for Osmo4/wxWidgets player..TP.B Loop (value: yes, no)specifies whether the presentation has to be restarted when done playing..TP.B ConsoleOff (value: yes, no)specifies whether application messages (script, buffering, download progress) are displayed in the console or not..TP.B Browser (value: string)specifies prefered browser for WWW anchors and scene graph viewing - Only used by Osmo4/wxWidgets..TP.B LookForSubtitles (value: yes, no)specifies if Osmo4 shall look for subtitle files when opening a presentation..TP.B PLEntry (value: unsigned int)indicates active playlist entry when player was last closed. Playlist backup is ".gpac_pl.m3u", stored in user home directory..TP.B StartupFile value: filename)specifies file to load upon startup of osmo4/MP4Client. If not specified, no file is loaded..TP.B NoMIMETypeFetch (value: yes, no)specifies if the player has to check for mime type when following hyperlinks, or only follow links of known extensions..TP.B LogFile (value: filename)specifies where to output GPAC's log. By default, the logs are written to stdout. Note that GPAC may be compiled without log support. This is not used by MP4Client..TP.B LogLevel (value: none, error, warning, info, debug)specifies the level of the log. By default, no log is performed..TP.B LogTools (value: a ':'-separated list of the following values)specifies which set of tools from GPAC should be logged. Available tools are:.brcore: libgpac core events..brcoding: bitstream formats (audio, video, scene)..brcontainer: container formats (ISO File, MPEG-2 TS, AVI, ...)..brnetwork: network data exept RTP trafic..brrtp: rtp, rtcp and rtsp trafic..brauthor : authoring tools (hint, import, export)..brsync: terminal sync layer..brcodec: terminal codec messages..brparser: scene parsers (svg, xmt, bt) and other..brmedia: terminal media object management..brscene: scene graph and scene manager..brscript: scripting engine messages..brcompose: composition engine (events, etc)..brrender: renderng engine (2D, 3D, etc)..brservice: network service management..brmmio: Audio/Video HW I/O management...SH SECTION "RecentFiles".LPThe "RecentFiles" section of the config file holds last accessed files (hardcoded to no more than 20) in the last access order. The keys are the file names and no value is used. This section is only used by GUI clients...SH SECTION "Systems".LPThe "Systems" section holds all configuration options for the MPEG-4 Systems engine. The following options are defined:.TP.B Language (value: 3-char code from ISO 639-2)specifies the user prefered language. This is used to select streams in case of alternate content in an audio object..TP.B AlwaysDrawBIFS (value: yes, no)if set, late BIFS frame will still be drawn. If not set, the scene won't be redrawn until BIFS streams are back in sync. This is by default off to keep better sync, but may be changed when testing heavy content or slow renderers..TP.B ForceSingleClock (value: yes, no)One big problem with MP4 files is that the notion of "duration" has been unclear for a long time, and most content available (audio-video files) specifiy a wrong BIFS duration. In such a case the movie cannot be controled/seek into..brAnother problem with ISMA streaming is that BIFS/OD don't use the same clock as audio/video, thus seeking the main timeline does not seek AV media. .brSetting the ForceSingleClock will handle both cases by using a single timeline for all media streams and settingthe duration to the one of the longest stream..TP.B ThreadingPolicy (value: Free, Single, Multi)specifies how media decoders are to be threaded. .brFree: lets decoders decide of their threading..brSingle: means that all decoders are managed in a single thread performing scheduling and priority handling..brMulti: means that each decoder runs in its own thread..TP.B Priority (value: low, normal, high, real-time)specifies the priority of the decoders (priority is applied to decoder thread(s) regardless of threading mode)..TP.B hardcoded_protos (value: list of strings separated by space)holds a list list of EXTERNPROTO URLs (NO OD_ID !!!) implemented in hard in the renderer - for development only..TP.B NoVisualThread (value: yes, no)specifies whether the visual rendering is done in the main codec manager or in a dedicated thread..TP.B DefAudioDec, DefVideoDec (value: string)Specifies which plugin to use by default for audio/video decoding. Example, "DefVideoDec=name".The name given is the name of the plugin to be used (same considerations as other plugins, cf above)..TP.B codec_XX_XX (value: string)Allows to specify default media plugin (audio/video) per stream type and object type. This is usefull if you have more than one decoder for a given type. The syntax is .B codec_AA_BB=pluginnamewhere AA is the hexadecimal MPEG-4 streamType value for the codec (0x04=visual, 0x05=audio) and BB is the hexadecimal MPEG-4 objectTypeIndication of the media (0x20 = MPEG-4 video, 0x40=MPEG-4 Audio, ...). The name given is the name of the plugin to be used (same considerations as other plugins, cf above)...SH SECTION "Rendering"The "Rendering" section holds all configuration options for the logical rendering engines, whether 2D or 3D. The following options are defined:.TP.B RendererName (value: string)specifies which renderer should be used. There are currently 2 renderers available in GPAC, "GPAC 2D Renderer" and "GPAC 3D Renderer". Renderers cannot be reloaded at run-time, the complete system must be restarted..TP.B Raster2D (value: string)specifies the 2D rasterizer to use for vectorial drawing. Used by 2D renderer (for everything) and 3D renderer (for textured text and gradients)..TP.B FrameRate (value: float)specifies the simulation frame-rate of the presentation - this value is also used by the MPEG-4 Systems engine to determine when a BIFS frame is mature for decoding..TP.B AntiAlias (value: None, All, Text)specifies antialiasing settings - whether the setting is applied or not depends on the graphics plugin/graphic card..brNone: no anti-aliasing.brText: anti-aliasing for text only.brAll: complete anti-aliasing.TP.B FastRender (value: yes, no)specifies whether rendering should target speed or quality - whether the setting is applied or not depends on the graphics plugin/graphic card..TP.B ForceSceneSize (value: yes, no)forces the scene to resize to the biggest bitmap available if no size info is given in the BIFS configuration..TP.B StressMode (value: yes, no)specifies that the renderer runs in worst case scenario, recomputing all vectorial paths, meshes, outlines and reloading textures (sending them to graphics card) at each frame..TP.B BoundingVolume (value: None, Box, AABB)specifies whether the bounding volume of an object shall be drawn or not. Note that the 2D renderer only uses rectangles as bounding volumes. The "AABB" value is used by the 3D renderer only, and specifies the object bounding-box tree shall be drawn...SH SECTION "Render2D"The "Render2D" section holds all configuration options for the 2D tile rendering engine. The following options are defined:.TP.B DirectRender (value: yes, no)specifies whether direct rendering should be used or not. In direct rendering mode, the screen is completely redrawn at each frame. In indirect rendering object positioning is tracked from frame to frame and dirty rectangles info is collected in order to redraw the minimal amount of the screen buffer.Whether the  setting is applied or not depends on the graphics plugin (currently all plugins handle both mode)..TP.B ScalableZoom (value: yes, no)specifies whether scalable zoom should be used or not. When scalable zoom is enabled, resizing the output window will also recompute all vectorial objects. Otherwise only the final buffer is stretched...SH SECTION "Render3D"The "Render3D" section holds all configuration options for the 3D openGL rendering engine. The following options are defined:.TP.B RasterOutlines (value: yes, no)specifies that outlining shall be done through openGL pen width rather than vectorial outlining. .TP.B PolygonAA (value: yes, no)specifies whether polygon antialiasing should be used in full antialiasing mode. If not set, only lines and points antialiasing are used..TP.B Wireframe (value: WireNone, WireOnly, WireOnSolid)specifies wireframe drawing options:.brWireNone: objects are drawn as solid.brWireOnly: objects are drawn as wireframe only.brWireOnSolid: objects are drawn as solid and wireframe is then drawn.TP.B DisableRectExt (value: yes, no)specifies whether openGL rectangular texture extension (GL_EXT_texture_rectangle or GL_NV_texture_rectangle) shall be used or not. .brIf "yes", textures whose dimensions are not power of two are rescaled except if hardware support non-power-of-two textures (GL_ARB_texture_non_power_of_two) natively.brIf "no" and extension is available, textures are used without rescaling. Note that in this case texture transformation are disabled..TP.B EmulatePOW2 (value: yes, no)enables power of 2 emulation. Ignored if openGL rectangular texture extension is enabled..brif set, video texture is not resized but emulated with padding. This usually speeds up video mapping on shapes but disables texture transformations..brif not set, video is resized to a power of 2 texture when mapping to a shape.