[FFmpeg-devel] [PATCH] fftools/ffmpeg_filter: fix SEGV in choose_pix_fmts after avio_close_dyn_buf

[Anton Khirnov]

Quoting Steven Liu (2021-12-01 09:37:52)
> From: Steven Liu <liuqi05 at kuaishou.com>
> 
> ret could be set to s->opaque->buffer in avio_close_dyn_buf, so it can
> be set to NULL, check NULL pointer deference after it should be ok.

I don't understand this reasoning. avio_close_dyn_buf() should produce
a non-NULL output buffer if something was written into it. Since this
branch is only taken when (enc->pix_fmts != NULL), something should
always be written, so the output buffer should be non-NULL and have a
non-zero size.

Under what circumstances will it happen that the output is NULL?

-- 
Anton Khirnov