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

[Mark Himsley]

On 01/11/13 14:45, Yusuke Nakamura wrote:
> 2013/11/1 Mark Himsley <mark at mdsh.com>
>
>> 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.
>>
>> [1] https://developer.apple.com/**library/mac/documentation/**
>> quicktime/QTFF/qtff.pdf<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<https://developer.apple.com/library/mac/documentation/quicktime/QTFF/qtff.pdf>page 178
>>
>> --
>> Mark
>>
>>
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>>
>>
>
> The patch itself, LGTM.
>
> Can you share one of such sample?

The files are copyright, but I've found the shortest file with sensible 
sound and could make it (~200MB) available to a limited number of people 
(not a mailing list).

-- 
Mark