Hi all, 2015-01-22 15:58 GMT+01:00 Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>: > 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? I am now working on the encoder part (for coda) which should do the same. But everything is documented from a decoder POV, not the encoder's... Is the mecanism already there, and the only thing which should be added is the ENC_CMD_STOP command ? Thanks, JM -- 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
