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isom: lpcm in mov default to big endian

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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.

This commit adds AV_CODEC_ID_PCM_S16BE as the first match for 4CC 'lpcm'.

[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

Reviewed-by: Yusuke Nakamura <muken.the.vfrmaniac@gmail.com>
This commit is contained in:
Mark Himsley 2013-11-01 11:22:53 +00:00 committed by Vittorio Giovara
parent db32f14c3d
commit 360022bd3b
1 changed files with 1 additions and 0 deletions
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libavformat/isom.c
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@ -270,6 +270,7 @@ const AVCodecTag ff_codec_movaudio_tags[] = {
{ AV_CODEC_ID_PCM_MULAW, MKTAG('u', 'l', 'a', 'w') },
{ AV_CODEC_ID_PCM_S16BE, MKTAG('t', 'w', 'o', 's') },
{ AV_CODEC_ID_PCM_S16LE, MKTAG('s', 'o', 'w', 't') },
{ AV_CODEC_ID_PCM_S16BE, MKTAG('l', 'p', 'c', 'm') },
{ AV_CODEC_ID_PCM_S16LE, MKTAG('l', 'p', 'c', 'm') },
{ AV_CODEC_ID_PCM_S24BE, MKTAG('i', 'n', '2', '4') },
{ AV_CODEC_ID_PCM_S24LE, MKTAG('i', 'n', '2', '4') },