[FFmpeg-devel] [PATCH] libavfilter/thumbnail filter, copy buffers instead of reference

Clément Bœsch u at pkh.me
Thu Feb 26 16:37:45 CET 2015

On Wed, Feb 25, 2015 at 10:31:09PM -0800, Chris Kennedy wrote:
> I forgot the copy of the original buffer, oddly if I copy it then causes
> things to crash at the end when the codec is freed, only for certain .avi
> mpeg4 and in the mpeg4 codec where it frees some data there.  I am digging
> in to that, but patch at least shows deeper into something odd going on.  I
> can just copy the R and G but not B and it doesn't hit the issue for this
> test video.  Seems really strange, before it seemed to be having backtraces
> in ffmpeg.c and buffer freeing conflicting or some problem, now when
> copying the buffers it is mpeg4 codec freeing and only if reading that blue
> value into the destination buffer, odd.

My guess is that you're just forcing the alloc & memcpy immediately
instead of having it postponed like it is currently (the filter holds a
reference to that frame). So you probably basically just hit your memory
limit at a different time, and just have another weird crash, I guess?

Maybe somewhere we're just missing a malloc check or something.


Clément B.
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