[gst-devel] Video streaming receiver problem

[Albert Costa]

Dear All,
I am trying to stream a live video over rtp/udp, but I'm facing some problems that I do not understand yet.
My sender pipeline is :
gst-launch ksvideosrc ! ffmpegcolorspace ! ffenc_mpeg2video gop-size=1 ! mpegtsmux ! rtpmp2tpay ! udpsink host=127.0.0.1 port=5000

On the receiver side, I have tried to catch the flow with VLC (settings : UDP, 127.0.0.1, port 5000). The player displays the video, but it is very jerky, a lot of blocks in the video frames are corrupted/misplaced. 

If I create instead a gst pipeline to receive the rtp flow:
gst-launch udpsrc port=5000 caps="application/x-rtp, media=video, clockrate=90000, encoding-name=MP2TS" ! rtpmp2tdepay ! ffdemux_mpegts ! ffdec_mpeg2video ! ffmpegcolorspace ! directdrawsink
then the video looks ok, but I see a lot of errors in the console:

0:00:00.828115000  5320   009C6488 ERROR               ffmpeg .:0:: skipped MB in I frame at 13 6
0:00:00.843740000  5320   009C6488 ERROR               ffmpeg .:0:: Warning MVs not available
0:00:04.671816000  5320   009C6488 ERROR               ffmpeg .:0:: skipped MB in I frame at 13 6
0:00:04.687440000  5320   009C6488 ERROR               ffmpeg .:0:: Warning MVs not available
0:00:04.703065000  5320   009C6488 ERROR               ffmpeg .:0:: Warning MVs not available
0:00:05.078060000  5320   009C6488 ERROR               ffmpeg .:0:: skipped MB in I frame at 15 9
0:00:05.093685000  5320   009C6488 ERROR               ffmpeg .:0:: ac-tex damaged at 13 6
0:00:05.156184000  5320   009C6488 ERROR               ffmpeg .:0:: skipped MB in I frame at 37 10
0:00:05.171809000  5320   009C6488 ERROR               ffmpeg .:0:: skipped MB in I frame at 39 26
0:00:05.187434000  5320   009C6488 ERROR               ffmpeg .:0:: slice mismatch
(...)
And if I replace ffdemux_mpegts by mpegtsdemux in the receiver (because I used mpegtsmux in the sender), the video is half blurred and jerky.

Does the problem of the video output quality come from the encoding itself? I've tried with several settings (gop-size, quantizer, bitrate...), none of them made the result better.
Any help is welcomed!
Regards,
Al

(Running gstreamer on windows with gst-winbuilds-0.10.4)


      
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