[FFmpeg-devel] [PATCH 1/5] avcodec/mjpegdec: Always reset got_picture at the beginnig of decoding

[Michael Niedermayer]

On Thu, Apr 14, 2022 at 05:56:30PM +0200, Andreas Rheinhardt wrote:
> Said field is set when parsing a SOF; yet a picture is only allocated
> if skip_frame is != AVDISCARD_ALL. This leads to a crash in the
> following case: If a jpeg is split into two parts, the first containing
> everything before the scans including the SOF and the second part
> containing the rest, and the first part is sent to the decoder with
> skip_frame set to AVDISCARD_ALL, got_picture is set, yet no picture
> is allocated. If the next part is sent with skip_frame set to
> AVDISCARD_NONE, the code presumes that a picture has been allocated,
> although it hasn't leading to segfaults.
> 
> Fix this by resetting got_picture at the beginning of decoding.
> 
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> ---
> This patch presumes that there is not use-case for partitioning
> the data corresponding to a single AVFrame accross multiple packets.
> I am not certain whether this is actually true, in particular
> wrt interlaced input where it might be common to put the data for
> one field into one packet.
> Anyway, no such use is covered by FATE.

This changes timestamps slightly for:
./ffmpeg -an -i ~/tickets/1915/m_noint.avi -an -bitexact -f framecrc -t 1 -

not sure thats intended

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Into a blind darkness they enter who follow after the Ignorance,
they as if into a greater darkness enter who devote themselves
to the Knowledge alone. -- Isha Upanishad
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