[FFmpeg-devel] AVCodecParserContext.keyframe does not match AVFrame.key_frame for an AVCHD sample

Robert Krüger krueger at lesspain.de
Fri Mar 8 13:22:54 CET 2013


I have a sample camera file for which only the first frame is reported
as a keyframe when decoding it (AVFrame.key_frame and ffprobe output
confirms that) but for some frames
AVCodecParserContext.keyframe is set to 1 and that would absolutely
make sense taking into account what I know about the camera's GOP size
from other sources. However, the field
AVCodecParserContext.convergence_duration is never set to any other
value but 0 and judging by its documentation it looks like it is the
one I should really use to identify recovery points when parsing the
stream. It would be nice if someone with knowledge of ffmpeg's h264
internals could tell me if I can use this to identify recovery points
in an h.264 stream or if the inconsistency between
AVCodecParserContext.keyframe and AVFrame.key_frame should be fixed or
if I'm getting it all wrong.

What shall I do? File a ticket in trac? The sample is the same as for
tickets 2336, 2337, 2338.

I would be grateful for some advice.



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