GPAC 2.4

We are happy to announce the release of GPAC 2.4

This release marks the beginning of GPAC in your browser with emscripten support, with a live demo at !

This release also brings many new features including pcap support, async net IOs, JIT packaging for on-demand content and better subtitle/CC support.

As usual, installers are available on for most common platforms.

Enjoy, give us feedback and spread the news!

Continue reading GPAC 2.4

GPAC documentation updates

Announcing New Documentation for GPAC

For over two decades, GPAC and MP4Box have been at the forefront of multimedia processing innovation, continuously evolving and expanding their capabilities. This journey has seen the software mature and grow in scope over time. The documentation, too, has accumulated and evolved, with specific portions even becoming deprecated. As the GPAC landscape widened, we saw a need for accessible, up-to-date documentation that was able to grow alongside our technologies.

Ten years ago as we moved to GitHub for our public version control server, we migrated to the github wiki system: a nice improvement in developer experience to produce documentation at the time. This move marked a significant step forward, enhancing the developer experience and facilitating the creation and sharing of knowledge.

But today, with the large amount of documentation now provided to cover usage of GPAC filters along MP4Box, we felt the GitHub Wiki had shown its limits: the combined lack of support for HTTP redirects and poor search functionality of GitHub’s Wiki made it less appealing compared to the many alternatives available these days for software documentation.

Introducing a better documentation solution based on mkdocs

We settled with the excellent mkdocs framework, using the popular materials for mkdocs theme. This transition is not merely a change of platform but a significant upgrade to how our community accesses and interacts with GPAC documentation.

The upgrade provides a more refined user experience, a nicer look and feel on any device, a light and dark mode, improved navigation, an intuitive layout and table of contents. 

The upgraded GPAC Wiki is now hosted in a github repository of its own, making it easier to welcome contributions to the documentation.

But most importantly, the new documentation is now instantly searchable, making it easier than ever to find the relevant information for your MP4Box and GPAC use cases:

We invite you to explore the new documentation site at

Your feedback is invaluable to us, you can contribute the documentation or share your suggestions for improvements as issues on github.

Website Update: Your Feedback is Essential

Dear GPAC Community,

Major updates have been made to the GPAC website. To improve clarity and structure, we have undertaken a comprehensive revision to enhance the user experience that is being deployed. 

Understanding Our Users

To ensure that the revamped website aligns with the needs and preferences of our community, we are keen to understand who is using GPAC, any potential gaps in our current website, and any additional insights you might be willing to share. Your feedback is invaluable to us, and we’d appreciate if you would complete the survey.

A Brief Overview of GPAC

GPAC, since its inception, has always been more than just a multimedia framework. With capabilities ranging from hybrid broadcast-broadband scenarios to virtual reality (VR) and 3D scenes, GPAC stands out in its versatility and innovation. Our commitment to standards, demonstrated by accolades such as the Emmy awarded to ISOBMFF in 2021, is a testament to our dedication to excellence.

The success of GPAC is a collective effort. From its beginnings as a startup in New York City in 2000 to its evolution as a leading open-source project, the commitment and expertise of our contributors have been pivotal. Our collaboration with esteemed institutions like Télécom Paris and partnerships with entities like Motion Spell have further enriched our journey. 

We are also deeply grateful to our major sponsor, Netflix, not only for their strong support of the developer community here at GPAC but also for their dedication to open standards and innovation. Their alignment with our vision was further exemplified last year when Netflix successfully integrated GPAC software into its global content operations.

Engage with Us

We invite you to share your thoughts via the survey. Whether you’re involved in video streaming, research, or are a developer keen on multimedia frameworks, your insights will shape the future direction of GPAC.

We appreciate your continued support and engagement with GPAC.

The GPAC team

GPAC 2.2

We are happy to announce the release of GPAC 2.2

This release marks the end of MP4Client/Osmo4/Osmo4Ios/Osmo4Android, with gpac being used for all platforms – Android app now supports running gpac and MP4Box command line as well as running the GUI.

This release also brings better support for MKV, DolbyAtmos and DolbyVision.

As usual, installers are available on for most common platforms.

Enjoy, give us feedback and spread the news!

Detailed changes:

Media Formats

  • 2-pass encoding for FFmpeg codecs other than libx264
  • Conversion filters for VTT, TXG3 and TTML
  • SubstationAlpha subtitle import (basic)
  • DVB subpictures in M2TS mux and demux
  • FFMPEG (mostly for Matroska) subtitle import and export (SRT/SSA to TX3G, TX3G to SRT, WebVTT and DVB subpictures)
  • EC3+Atmos signaling support
  • ALAC support
  • Improved DolbyVision muxing

Media player

  • subtitle delay and position adjustment
  • audio delay adjustment


  • allow numbers and media types as identifiers for track actions
  • dlba option to update atmos+ec3 signaling


  • UTC-based range extraction in reframer
  • Thumbnail generator filter
  • Added unframer filter
  • FFMPEG bitstream filters support
  • initseg support in mp4dmx filter
  • Access to GPU textures of decoders in Python and JSF bindings (glpush filter for tests)
  • Chapters editing and original timestamp dispatch in reformer range extraction
  • dual in-band and out-of-band parameter set support in dasher
  • non-blocking IO for RTSP and HTTP servers/clients
  • RTSP over HTTP in rtsp server
  • Source-Specific multicast for udp and rtp inputs
  • User Authentication for HTTP and RTSP servers
  • TLS support for RTSP client and server
  • Per-filter buffering options


  • ClearKey support in dasher and decryption


  • QT metadata tags in MP4Box and qt muxer
  • support for some packet properties in URL templates

​Press Release: Motion Spell Deploys GPAC Open Source Software with NETFLIX

For Immediate Release, Tuesday, 8th November 2022

Motion Spell deploys GPAC Open Source Software with Netflix to build a flexible encoding and packaging platform

​GPAC Licensing – exclusively handled by Motion Spell, provides enhanced support for our industrial/commercial users. See our latest news release “Motion Spell Deploys GPAC Open Source Software with NETFLIX” 8th November 2022.

Read the press release here.