On Sat, 21 Nov 2020 at 23:01, Dmitry Osipenko <digetx@xxxxxxxxx> wrote: > > 22.11.2020 04:02, Ezequiel Garcia пишет: > > Hi Dmitry, > > > ... > >> +++ b/drivers/staging/media/tegra-vde/TODO > >> @@ -0,0 +1,4 @@ > >> +TODO: > >> + - Implement V4L2 API once it gains support for stateless decoders. > >> + > >> +Contact: Dmitry Osipenko <digetx@xxxxxxxxx> > > > > The API for H264 stateless decoding is ready. > > See https://lkml.org/lkml/2020/11/18/795. > > Hello Ezequiel, > > Thank you for the notification! My last attempt at implementing V4L API > support was about a year ago and it stopped once I realized that there > is no userspace which uses that API. FFMPEG and chromium browser had > some kind of V4L support, but it all was oriented at downstream driver > stacks, and thus, not usable. Do you know what is the current status? > The bulk of the API, which relies on the stateless decoder interface [1], and H264 stateless V4L2 controls has been ready for some time now, and there are various implementations supporting it. Chromium supports it [2], and I've tested it on chromebooks, through chromeos builds. We haven't tried a non-chromeos build, and I would say it's quite some work. GStreamer support is available as well. See [3] which should work for the latest H264 controls (the ones being moved out of staging). LibreELEC developers maintain an Ffmpeg branch [4], I expect it will be updated for the latest H264 controls soon, and hopefully merged in mainline Ffmpeg. GStreamer and Ffmpeg are relatively straightforward to build and test. Thanks, Ezequiel [1] https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/dev-stateless-decoder.html [2] https://github.com/chromium/chromium/tree/master/media/gpu/v4l2 [3] https://gitlab.freedesktop.org/ezequielgarcia/gst-plugins-bad/-/tree/h264_stable_uapi [4] https://github.com/Kwiboo/FFmpeg/tree/v4l2-request-hwaccel-4.3. > > One minor comment below. > > > ... > >> + // PPS > >> + __u8 pic_init_qp; > >> + __u8 deblocking_filter_control_present_flag; > >> + __u8 constrained_intra_pred_flag; > >> + __u8 chroma_qp_index_offset; > >> + __u8 pic_order_present_flag; > >> + > > > > This seems to be bottom_field_pic_order_in_frame_present_flag, > > as there is no "pic_order_present_flag" syntax element. > > Correct, looks like I borrowed that name from the libvdpau API. > > https://vdpau.pages.freedesktop.org/libvdpau/struct_vdp_picture_info_h264.html#a405f7ef26ea76bb2c446e151062fc001
