[FFmpeg-devel] [PATCH] avformat/riff: remove useless tag correlation 'mpg2'->MPEG1VIDEO.

[Michael Niedermayer]

On Tue, Aug 01, 2017 at 02:50:27PM +0300, Александр Слободенюк wrote:
>  This is actually a bug, that just doesn't affect anything.
>  First  of all, the logic of functions that work with ff_codec_bmp_tags
>  is "One tag -- one codec id", or "one codec id for one tag".
>  
>  Also  if  you  write  this tag as MPEG2VIDEO, and then read the header
>  (all by ffmpeg), it will interpret as MPEG1VIDEO:
>  
>  ffmpeg -i whatever -vcodec mpeg2video test.avi
>  && gdb ffprobe_g
>  
> (gdb) break avi_read_header
> (gdb) r -i test.avi
> (gdb) finish
> (gdb) p s->>streams[0]->codecpar->codec_id
> 
>  $1 = AV_CODEC_ID_MPEG1VIDEO
>  
>  
>  if  you  will  write an mpeg1video , it will be created with tag
> 'mpg1',    not    'mpg2'    in    all   cases   (because   correlation
> AV_CODEC_ID_MPEG1_VIDEO   --  'mpg1')  stands  before  'mpg2'  tag  in
> ff_codec_bmp_tags:
> 
> ffmpeg -i whatever -vcodec mpeg1video test.avi
>     (output)
>     ...
>     (output)
>     Stream #0:0: Video: mpeg1video (mpg1 / 0x3167706D),
>         
> So, this patch does not affect on writing mpeg1video to riff files.

>  riff.c |    1 -
>  1 file changed, 1 deletion(-)
> 7d4eaf028a197fd2aebdfe7c970de0da61a22055  0001-avformat-riff-remove-useless-tag-correlation-mpg2-MP.patch
> From ab7eefb51eeec5ff0c10f571d468f61c82a84eeb Mon Sep 17 00:00:00 2001
> From: Aleksandr Slobodeniuk <alenuke at yandex.ru>
> Date: Tue, 1 Aug 2017 14:48:39 +0300
> Subject: [PATCH] avformat/riff: remove useless tag correlation
>  'mpg2'->MPEG1VIDEO.

applied

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Why not whip the teacher when the pupil misbehaves? -- Diogenes of Sinope
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