cdg: set AV_PKT_FLAG_KEY

[gdesmott]

While integrating cdg support into gstreamer-ffmpeg (  https://bugzilla.gnome.org/show_bug.cgi?id=653493 ) I had to set the AV_PKT_FLAG_KEY on its packet to get it working.

I'm not a ffmpeg (or gst) expert but that seems like the right thing to do as this codec doesn't rely on key frames.

[gdesmott]

patch

[gdesmott]

Also reported:  http://bugzilla.libav.org/show_bug.cgi?id=55

[michael]

Thanks for pointing at this problem, ive succeeded to fix this in a way with which seeking works with my test file and only a subset of frames marked as keyframes.
Ill push it into master git after a bit more testing.
Also if you find files with which my fix doesnt work, please report them to us.

[gdesmott]

I tried using cdg.c from efb1ce28b26b66f1f72f85fcdfaf16d7fe6519fe and that doesn't work properly.

gst does decode the video but some frames are missing and it's not synced with the audio.

My gst-ffmpeg patch is  https://bugzilla.gnome.org/show_bug.cgi?id=653493#c6
I'm attaching my test app and files as well.

[gdesmott]

cdg file

[gdesmott]

I use: "gst-launch filesrc location=a.cdg ! ffdemux_cdg ! ffdec_cdgraphics ! ffmpegcolorspace ! ximagesink"