[FFmpeg-devel] lpcm in mov default to big endian

[Paul B Mahol]

On 11/1/13, Mark Himsley <mark at mdsh.com> wrote:
> It is my understanding that "Unless otherwise stated, all data in a
> QuickTime movie is stored in big-endian byte ordering" [1] in MOV files.
>
> I have a couple of thousand files, which technically are invalid because
> their sound sample description element 4CC is 'lpcm' but its version is
> 0 - and "Version 0 supports only uncompressed audio in raw ('raw ') or
> twos-complement ('twos') format" [2]
>
> Because isom.c only contains a mapping for 4CC 'lpcm' to
> AV_CODEC_ID_PCM_S16LE, these files have their audio decoded as LE when
> it is actually BE.
>
> Attached patch adds AV_CODEC_ID_PCM_S16BE as the first match for 4CC
> 'lpcm'.
>
> This is not tested for regressions in fate, but makes 4CC 'lpcm' match
> many other 4CCs in isom.c, and makes my files decode correctly.
>
> Please comment.

I guess le variant would then be mcpl.

>
> [1]
> https://developer.apple.com/library/mac/documentation/quicktime/QTFF/qtff.pdf
>
> page 21
> [2]
> https://developer.apple.com/library/mac/documentation/quicktime/QTFF/qtff.pdf
>
> page 178
>
> --
> Mark
>
>