Le mercredi 30 janvier 2019 à 15:17 +0900, Tomasz Figa a écrit : > > I don't remember saying that, maybe I meant to say there might be a > > workaround ? > > > > For the fact, here we queue the headers (or first frame): > > > > https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/blob/master/sys/v4l2/gstv4l2videodec.c#L624 > > > > Then few line below this helper does G_FMT internally: > > > > https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/blob/master/sys/v4l2/gstv4l2videodec.c#L634 > > https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/blob/master/sys/v4l2/gstv4l2object.c#L3907 > > > > And just plainly fails if G_FMT returns an error of any type. This was > > how Kamil designed it initially for MFC driver. There was no other > > alternative back then (no EAGAIN yet either). > > Hmm, was that ffmpeg then? > > So would it just set the OUTPUT width and height to 0? Does it mean > that gstreamer doesn't work with coda and mtk-vcodec, which don't have > such wait in their g_fmt implementations? I don't know for MTK, I don't have the hardware and didn't integrate their vendor pixel format. For the CODA, I know it works, if there is no wait in the G_FMT, then I suppose we are being really lucky with the timing (it would be that the drivers process the SPS/PPS synchronously, and a simple lock in the G_FMT call is enough to wait). Adding Philipp in CC, he could explain how this works, I know they use GStreamer in production, and he would have fixed GStreamer already if that was causing important issue. Nicolas
