[Ffmpeg-devel] Re: [PATCH] mpegvideo remove fourcc upper case conversion

Baptiste Coudurier baptiste.coudurier
Tue Aug 22 21:47:19 CEST 2006


Michael Niedermayer wrote:
> Hi
> On Tue, Aug 22, 2006 at 06:52:19PM +0200, Baptiste Coudurier wrote:
>> Hi
>> Here is a patch to remove uppercase conversion of fourcc. That cause
>> conversion if mpeg essence is stored in container which already have a
>> fourcc (mov), and IMHO a codec should not alter fourcc.
> rejected, this will break decoding of many old divx and xvid files
> grep for codec_tag ...

IMHO, like I said codec should not alter fourcc. Why not matching both
cases or use sub_id or having (avi ?) demuxer converting it to upper case ?

> btw, speaking of breaking stuff, did you test that the unconditional
> setting of AVCodecContext.width/height in the mov/mp4 demuxer has no 
> negative effects if they are wrong? (they are often wrong for mpeg4)
> [...]

I thought lavc would always override width and height for mpeg4, and
having tested on all files I got, I saw no problems. Do you know a file
which cause problem ?

Also why not setting them ? What would be the policy ? Not setting
fields which can cause problem with some maybe broken files ? I don't
know... but that is not only related to width and height IMHO. I admit I
don't like workarounds much :/

Btw, did you have a look at 2 patches I posted earlier, to remove usage
of 'wide' atom and demuxing dv in mov ?

Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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