GstSpringHackfest2017: a quick report

Two weeks ago was the GStreamer Spring Hackfest 2017 and I am very happy about how it went. I have the feeling that most of the attendees had a good time, and made some progress in their projects. I want to thank all the people that participated, in some way or another.

Along that weekend when the hackfest happened, besides my duties as organizer (with a lot of help from my colleagues at Igalia), I managed to hack a bit on GstPlayer, proposing the missing API for setting the subtitles font description (782858). Also I helped Nicolas a bit with the upstreaming of the v4l2 video encoder (728438). Julien Isource and I talked about the missing parts of DMABuf support in gstreamer-vaapi, in particular the action path when the new libva API, for importing and exporting DMABuf, got merged (779146). With Thibault we played with the idea of a Jenkins server doing CI for gstreamer-vaapi. Also I did some kernel debugging, and found out why kmssink failed in db410c when the caps changed from RGB to YUV, thus Rob Clark cooked a patch.

Finally, I worked on a time-lapse video of the hackfest’s main room, only using GStreamer with gstreamer-vaapi in an Atom-based NUC. You can glance the code of the video grabber. Thanks to Luis de Bethencourt for the original idea and code.

GStreamer Spring Hackfest 2017 & GStreamer 1.12

Greetings earthlings!

Two things:


GStreamer 1.12 is out! And with it, gstreamer-vaapi. Among other new features and improvements we have:

  • GstVaapiDisplay now inherits from GstObject, thus the VA display logging messages are better and tracing the context sharing is more readable.
  • When uploading raw images into a VA surfaces now VADeriveImages are tried first, improving the upload performance, if it is possible.
  • The decoders and the post-processor now can push dmabuf-based buffers to downstream under certain conditions. For example:
    GST_GL_PLATFORM=egl gst-play-1.0 video-sample.mkv --videosink=glimagesink
  • Refactored the wrapping of VA surface into gstreamer memory, adding lock when mapping and unmapping, and many other fixes.
  • Now vaapidecodebin loads vaapipostproc dynamically. It is possible to avoid it usage with the environment variable GST_VAAPI_DISABLE_VPP=1.
  • Regarding encoders: they have primary rank again, since they can discover, in run-time, the color formats they can use for upstream raw buffers and caps renegotiation is now possible. Also the encoders push encoding info downstream via tags.
  • About specific encoders: added constant bit-rate encoding mode for VP8 and H265 encoder handles P010_10LE color format.
  • Regarding decoders, flush operation has been improved, now the internal VA encoder is not recreated at each flush. Also there are several improvements in the handling of H264 and H265 streams.
  • VAAPI plugins try to create their own GstGL context (when available) if they cannot find it in the pipeline, to figure out what type of VA Display they should create.
  • Regarding vaapisink for X11, if the backend reports that it is unable to render correctly the current color format, an internal VA post-processor, is instantiated (if available) and converts the color format.



GStreamer Spring Hackfest 2017 is in less than two weeks!

It is going to be held at Igalia premises inCoruña. Keep an eye on it 😉