[FFmpeg-devel] [PATCH] avformat/mux: Check pkt->stream_index before using it

[Marton Balint]

On Sun, 10 May 2020, Anton Khirnov wrote:

> Quoting Andreas Rheinhardt (2020-05-08 00:55:00)
>> This commit fixes two recent regressions both of which are about using
>> pkt->stream_index as index in an AVFormatContext's streams array before
>> actually comparing the value with the count of streams in said array.
>> 96e5e6abb9851d7a26ba21703955d5826ac857c0 did this in
>> prepare_input_packet() and 64063512227c4c87a7d16a1076481dc6baf19841 did
>> likewise in write_packets_common().
>> 
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
>> ---
>> The same error in the same file applied on the same day by two different
>> people. How unlikely.
>
> How is it a regression? Isn't it rather invalid API use?

Fun fact: 7b03b65bf0d02519c86750d2da33f413e11cf0c6

Yes, it is kind of invalid API use, but since the check is already there, 
we should make it actually worthwile.

>
> Not that I object to having a check. But then why is check_packet()
> called so deep and not immediately on entry to the muxer?

I guess it is not that deep, but recent factorization efforts hidden it a 
bit.

Regards,
Marton