Bootlin at the Linux Media Summit 2018

This year’s edition of the Linux Media Summit happened a month ago, in Edinburgh, right after the Embedded Linux Conference. Since we were already at the ELCE, and that we’ve been more and more involved in the media community thanks to our work on the Allwinner CSI driver and more importantly the Cedrus driver, it was natural for us to attend.

The media summit is usually a meeting to discuss the hot topics, so the whole day was a mix and match of various status updates and discussions on the future needs and developments around the Video4Linux2 framework.

Linux Media Summit attendees

Most of the discussion was about how to improve the contributor’s experience and improve the maintenance. The DRM subsystem was used as an example, since the number of patches are in the same order of magnitude, and a number of v4l2 contributors are also contributing to DRM drivers. Part of the improvement of both the maintenance and contribution experience will also come through some CI work, so there was a lot of discussions on how to improve the already existing tools (such as v4l2-compliance) but also how to setup some automatic tooling to run those tests as early as possible.

A good part of the day was also spent on dealing with the current developments, such as the Request API we’ve used in the Cedrus driver, and how to integrate that API into popular multimedia frameworks like gstreamer or ffmpeg. It looks like our libva implementation was well received, so it will probably be made standard and hosted on linuxtv.org in the near future. Other developments discussed were fault tolerant v4l2, in order to deal with video pipelines where one or several components might not work anymore, and storing the v4l2 controls state in a persistent way.

It was overall a very productive day, and it’s always nice to meet people you interact with over mailing list and IRC on a regular basis. If you want more information, you can read the extensive report.

Allwinner VPU support in mainline Linux November status update

Since our previous update back in September, we continued the work to reach the goals set by our crowdfunding campaign and made a number of steps forward. First, we are happy to announce that the core of the Cedrus driver was approved by the linux-media maintainers! It followed the final version of the media request API (the required piece of media framework plumbing necessary for our driver).

Both the API and our driver were merged in time for Linux 4.20, that is currently at the release candidate stage and will be released in a few weeks. The core of the Cedrus driver that is now in Linus’ tree supports hardware-accelerated video decoding for the MPEG-2 codec. We have even already seen contributions from the community, including minor fixes and improvements!

We have also been following-up on the other features covered by our crowdfunding campaign and made good progress on bringing them forward:

  • The series bringing H.264 decoding to our driver was updated for a second revision on November 15, rebased atop the upcoming Linux release and including a number of fixes as well as documentation;
  • H.265 decoding support followed with a second version sent on November 23, based on the updated H.264 series and bringing various minor improvements over the first iteration;
  • The patch series for the display engine DRM driver that adds support for the tiled YUV format used by the VPU was also updated, significantly reworked and submitted again on November 23;
  • Finally, we submitted a patch series adding support for the A64 and H5 Allwinner SoCs in the Cedrus VPU driver on November 15.
A64 and H5 boards provided by our sponsors Olimex and Libretech, now supported in Cedrus

With these patch series well on their way, we are closer than ever to delivering the remaining goals of the crowdfunding campaign!