Hi, Am Donnerstag, den 11.12.2014, 15:47 +0100 schrieb Hans Verkuil: > Hi Pawel, > > On 12/11/14 15:42, Nicolas Dufresne wrote: > > Le jeudi 11 décembre 2014 à 11:00 -0200, Fabio Estevam a écrit : > >> Hi, > >> > >> I am running Gstreamer 1.4.4 with on a imx6q-sabresd board and I am > >> able to decode a video through the coda driver. > >> > >> The pipeline I use is: > >> gst-launch-1.0 filesrc > >> location=/home/H264_test1_Talkinghead_mp4_480x360.mp4 ! qtdemux ! > >> h264parse ! v4l2video1dec ! videoconvert ! fbdevsink > > > > This is a known issue. The handling of EOS and draining is ill defined > > in V4L2 specification. We should be clarifying this soon. Currently > > GStreamer implements what was originally done in Exynos MFC driver. This > > consist of sending empty buffer to the V4L2 Output (the input), until we > > get an empty buffer (bytesused = 0) on the V4L2 Capture (output). > > > > The CODA driver uses the new method to initiate the drain, which is to > > send V4L2_DEC_CMD_STOP, this was not implemented by any driver when GST > > v4l2 support was added. This is the right thing to do. This is tracked > > at (contribution welcome of course): > > > > https://bugzilla.gnome.org/show_bug.cgi?id=733864 > > > > Finally, CODA indicate that all buffer has been sent through an event, > > V4L2_EVENT_EOS. This event was designed for another use case, it should > > in fact be sent when the decoder is done with the encoded buffers, > > rather then when the last decoded buffer has been queued. When correctly > > implemented, this event cannot be used to figure-out when the last > > decoded buffer has been dequeued. > > > > During last workshop, it has been proposed to introduce a flag on the > > last decoded buffer, _LAST. This flag could also be put on an empty > > Are you planning to work on this? That was my assumption, but it's probably > a good idea to check in case we are waiting for one another :-) I had another look at the ELC-E 2014 V4L2 codec API document and have tried to implement the proposed decoder draining flow in an RFC: "Signalling last decoded frame by V4L2_BUF_FLAG_LAST and -EPIPE": http://comments.gmane.org/gmane.linux.drivers.video-input-infrastructure/87152 Are you planning to pour the workshop's codec API document into a V4L2 documentation patch? regards Philipp -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
