GPAC goes 10 bit

We have introduced support for 10 bit HEVC profile last week in GPAC, using the great openHEVC decoder. Doing so, we also introduced support for 10 bit display. The support requires a graphics card capable of driving a 10 bit display; this support is usually enabled via the control application of your GPU. Do not worry, 10-bit video will still show in 8 bit if your graphics card doesn’t handle 10 bit output !

The setup currently requires manual configuration of the player. Edit the GPAC configuration file and set the following keys:

You can also enable it from the command line:

This has only been successfully tested on windows, using the “DirectX Video Output” module of GPAC. It has been tested on a ATI FirePro W5000 GPU but should work the same on other ATI models or NVidia ones.
Support for 10 bit is also enabled on X11 (same config) but doesn’t seem to work with the FirePro W5000.

We welcome any feedback you may give on the compatibility of GPAC’s 10bit support on any GPUs !


5000th commit, 10 years of open-source software

Dear followers,

We are happy to celebrate the 5000th commit on the GPAC codebase.

GPAC is an adventure started by Jean Le Feuvre in 2000. It has been made open-source in 2003. Since then GPAC has grown regularly to provide you with new features around multimedia and streaming : )

It can now package MP4 and MPEG2-TS using MP4Box and MP42TS, stream with the DASH, HLS, RTP, … protocols , and play back with Osmo4 on many platforms (desktop, mobile, embedded). We even have a live transcoder named DashCast!

2013 has also been an important year for our professional users. They are now able to get professional licensing and services using GPAC Licensing. Don’t worry, GPAC will remain open-source software : )

According to the analytics site, GPAC has over 650k lines of code and has needed 177 years of effort!


If you are interested in statistics, you can read this.

The GPAC team

MP4 demuxer examples

Dear followers,

At the request of some people, we have added to GPAC some sample applications demonstrating how to use GPAC to demux MP4 files. They are not full applications, just examples taking some MP4 files as input and displaying some information about the media samples contained in the file.

So far, we have added 3 sample applications:

  • a basic demuxer called ‘bmp4demux’ capable of reading and dispatching media access units from fragmented or non-fragmented MP4 files, progressively (i.e. while the file is being written);
  • a segment based demux called ‘segmp4demuxer‘ capable of dispatching media units from media segments, where the input data is framed.  This is what is used for the DASH support;
  • and a more advanced demuxer, called ‘fmp4demux’ capable of dispatching media units in streaming mode (i.e. reclaiming resources once media units have been dispatched), where the input data comes from fragmented mp4 but is not framed, i.e. the data in the buffer passed to the demuxer does not start or end at segment or fragment boundaries.

Continue reading

How to file a bug properly

GPAC is becoming quite a large piece of software and, unfortunately despite our care, is not bug-free… This is where you, as GPAC users, can help. If you discover a problem, you can report it using our bug tracker.

Filing a bug, if this is done well, is the best way to ensure that the problem will be fixed. However, if the bug is not filed correctly, it is the best way to ensure that it won’t get fixed. This post gives guidelines on how to file a bug, properly. Continue reading

The SVN repository was moved!

Dear users,

For maintenance and upgrade reasons, our host SourceForge has migrated GPAC to its new platform. You may see some changes in the forums but you’ll likely see that ‘svn update’ stays stucked at revision 4614.

Please ensure you have changed your local repository by following this tutorial: .

For most users, this command will make the deal:

To check out GPAC:

Sorry for the inconvenience. Please use our forums if needed.



HEVC Live Showcase

As part of the 4Ever project, GPAC is currently on-air at Roland Garros, the French Tennis Open, for a world premiere live broadcast of 720p50 HEVC over DVB-T2 (broadcasted in Rennes through ImaginLab), IPTV and MPEG-DASH ! If you’re in town and want to check it out, drop us a line or stop at the RGLab booth !


This week was held in Incheon, South Korea, the 104th MPEG meeting. For this occasion, the GPAC team worked hard to prepare the following contribution.

This contribution discusses SVC, WebVTT and in particular the support for MPEG-HEVC (High Efficiency Video Coding, a.k.a. H.265) packaging, streaming and playback in GPAC. I’ve extracted the HEVC related part of this contribution in this post. Continue reading