[Libav-user] "no picture" from decoding single h264 keyframe

[Andrey Utkin]

2014-04-03 12:33 GMT+03:00 cyril poulet <xenosender at gmail.com>:
> I'm no expert, but it would not surprise me much if the flag indicated only
> the beginning of the key frame, and not that it contains an entire key
> frame...
> Also, I'm not sure that you can really rely on it, the AVFrame->pict_type is
> much more reliable

You are right, looks AV_PKT_FLAG_KEY marks a "beginning of key frame".
Some log excerpt is below for justification. You can see a large first
AVPacket marked as key, and one small following AVPacket. The decoder
returns actual picture (if I type) after decoding both of them.
Thanks to all for sharing ideas, especially to Cyril.

<30>Apr  3 20:50:23 : D(3/axis): read AVPacket: stream_index: 0, size:
15080, flags: 1, dts: -9223372036854775808, pts: -9223372036854775808
<30>Apr  3 20:50:23 : D(3/axis): read AVPacket: stream_index: 0, size:
66, flags: 0, dts: -9223372036854775808, pts: 3560
<30>Apr  3 20:50:23 : D(3/axis): read AVPacket: stream_index: 0, size:
10232, flags: 0, dts: 3560, pts: 7198
...
<30>Apr  3 20:50:23 : D(3/axis): mo proc block decodes packet, size
15080, flags 1
<30>Apr  3 20:50:23 : D(3/axis): [libav] debug no picture
<30>Apr  3 20:50:23 : D(3/axis): no picture from decoding frame in mo proc
<30>Apr  3 20:50:23 : D(3/axis): mo proc block decodes packet, size 66, flags 0
<30>Apr  3 20:50:23 : D(3/axis): Decoded picture type: I (1)
<30>Apr  3 20:50:23 : D(3/axis): mo proc block decodes packet, size
10232, flags 0
<30>Apr  3 20:50:23 : D(3/axis): Decoded picture type: P (2)

-- 
Andrey Utkin