Player Features

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Foreword

A true multimedia player is a complex system involving networking, media and user interactions management, rasterizing, etc. The following section is a more or less exhaustive list of supported features in the GPAC player. Since the GPAC player is mostly a frontend to the filter engine in GPAC, most features from Filters are supported.

With the deprecation of NPAPI and browser plugins in general, GPAC player can no longer be embedded in web browsers.

VRML-Based Scene Graphs

• Complete scene graphs for MPEG-4/VRML and X3D, configurable through included scene graph generators.
• All common interactivity types (events and routes, interpolators, conditionals, MPEG-4 valuators and X3D event filters).
• ECMAScript 2020 support through QuickJS engine.
• Full-feature PROTO and EXTERNPROTO support.
• MPEG-4 InputSensor (KeySensor, Mouse and StringSensor), X3D KeySensor and StringSensor support.
• Loading from binary (TS or MP4), text (bt) and XML (XMT-A)
• SAX Progressive loading of XMT and X3D files (text and gziped).

The status of VRML/BIFS implementation in GPAC can be checked here.

The status of X3D implementation in GPAC can be checked here.

MPEG-4 Systems specific tools

• ObjectDescriptor decoding.
• ObjectContentInformation and IPMPX decoding (disabled in default builds).
• BIFS Command Decoder with quantization, proto, script and predictive MF Field decoding.
• LASeR Decoder with LASeRScript support.

Hardcoded EXTERNPROTO nodes

GPAC extends VRML/BIFS node set through its hardcoded proto mechanism. These are protos with predefined URLs and interfaces, allowing BIFS compression without modifying the language syntax. These nodes are identified by a proto URN starting with urn:inet:gpac:builtin:.

The following hardcoded protos are available:

• PlanarExtrusion: extrude a 2D shape (except text) along a 2D path
• PathExtrusion: extrude a 2D shape, including text, along a 2D path
• PlaneClipper: set a 3D plane clipper
• VRGeometry: portion of a sphere, used for 360 video tiling
• VRHud: build a simple head-up display in 360 videos showing various views of the sphere
• OffscreenGroup: draw all children (2D only) into offscreen memory
• DepthGroup: assign depth to 2D children
• DepthViewPoint: configure depth position and scaling for 2D depth
• IndexedCurve2D: Curve2D reusing sub-paths through indexes
• Untransform: reset current transformation to identity
• StyleGroup: force all children node to use the appearance given in the StyleGroup

SVG-based Scene Graph

• SVG 1.2 Tiny scene graph - see SVG implementation details
• Complete LASeR scene graph (subset of SVG Tiny 1.2)
• Some SVG 1.1 Full extensions
• XML events and SMIL animation for SVG content
• uDOM (MicroDOM) ECMAScript support through QuickJS engine
• SAX Progressive loading of SVG files (text and gzipped)

Scene Renderer

The media stream composition (renderer) is performed by the Compositor filter interacting with the underlying filter session.

Media Stream Management

• Playback for audio, video, texts and scene codecs
• Synchronization and media management, support for arbitrary number of timelines
• Time control and segment descriptors (media control, media sensor)
• Dynamic insertion/update/removal of objects and streams
• Inline scene support (local or remote) with MediaControl/MediaSensor support

Audio rendering

• Multichannel support
• Integer up/down sampling with mediaSpeed handling in 8, 16, 24, 32 bit or 32 floating point
• Multichannel to stereo mapper
• N-sources, M-channels software mixing
• Per-channel volume support
• Lip-sync management

2D Rendering

• Complete and differential rendering
• Full alpha support (including ColorTransform)
• Text drawing in vectorial mode or textured mode
• Texturing, gradients, user interaction (and user interaction on composite textures)
• Hardware accelerated blit if available in output plugin

3D Rendering

• Graphics backend: OpenGL and OpenGL-ES
• Alpha-blending (z-sorting), fast texturing when available (support for rectangular textures and non-power-of-2 textures), gradients, X3D RGBA colored meshes
• Frustum culling, ray-based node picking, decent collision detection through AABB tree, gravity
• Navigation in main screen and in 3D layers, viewpoint selection
• Text drawing in vectorial mode or textured mode (supports NICE text under OpenGL!)

Media Decoders

Decoders included in default builds:

• PNG, JPEG (libJPEG) and JPEG-2000
• MPEG-4 AAC, MPEG-1/2 audio, Dolby AC-3
• MPEG-1/2/4, H264|AVC, SVC, HEVC, L-HEVC
• AMR speech codec using 3GPP fixed-point reference code
• All codecs supported by FFMPEG
• Xiph Media codecs: Vorbis, Theora (FLAC and Opus supported through FFMPEG)
• SRT / 3GPP timed text / MPEG-4 Streaming Text decoder /WebVTT (rendering done through GPAC)

Networking

Any possible input from GPAC filter architecture is supported by the player. This includes:

• File access from local drive, HTTP download, pipes and sockets.

• MP4, 3GP, MP3/Shoutcast, JPEG, PNG, OGG/Icecast, AMR/EVRC/SMV, SAF, raw YUV and PCM

• AAC files and radio streams (icecast AAC-ADTS)

• Subtitles (SRT/SUB/TeXML/TTXT/WebVTT formats)

• MPEG-2 TS files and IP streams (and experimental support for DVB for linux)

• MPEG-DASH, HLS and Smooth. This includes:

  • playback from an HTTP(s) server or from local storage for test purposes.
  • media segments based on TS and ISOBMF, with 3GPP timed text support
  • static (on demand) and dynamic (live) sessions
  • multiple period support
  • group selection support
  • independent component download (one adaptation set for audio, one for video)
  • most MPD syntax is supported
  • bitstream switching mode (single init segment) and non-bitstream switching mode
  • manual quality switching by using ctrl+h and ctrl+l
  • basic automatic quality switching when playing HTTP urls
  • tiling, gaze and decoding speed adaptation

• SDP input - RTP/RTSP streaming including RTP/UDP streaming, RTP over RTSP and HTTP tunneling of RTP traffic (QuickTime/Darwin Streaming Server). RTP Payload formats supported are:

  • RFC 3016 for MPEG-4 Simple Profile video and simple LATM AAC
  • RFC 3640 for any form of MPEG-4 streams (audio, video, systems)
  • RFC 3267 for AMR audio (narrow-band, octet-align format only)
  • RFC 2250 for MPEG-1/2 audio and video and MPEG-2 TS
  • RFC 2429 for H263 video used by 3GPP (no VRC, no extra Picture Header)
  • RFC 3984 for H264/AVC video (only STAP-A, FU-A and regular NAL units)
  • RFC 7798 for H265|HEVC video (AP, FU and regular NAL units)

• Generic input using FFMPEG libavformat, supports most AV containers known (MPEG, VOB, AVI, MOV ...) and many protocols

• Generic frame grabber FFMPEG libavdevice, supports many capture devices

Available plugins

Audio output

• Microsoft DirectSound (with multichannel support)
• Microsoft WaveOut
• ALSA
• PulseAudio
• Jack
• Linux OSS
• SDL (desktop and iOS)
• Android audio output

Video output

• Microsoft DirectDraw (supports hardware YUV and RGB stretch)
• SDL (desktop and iOS)
• X11 with OpenGL and shared memory support
• Android OpenGL video output

Font reading

• FreeType2 for TrueType font outline extraction

Filters plugin

Filter plugins defined for GPAC can also be used by the player. It is however not yet possible to configure the input filter chain of the player.