[FFmpeg-devel] LPCM for mpeg-ts, the second

Christian P. Schmidt schmidt
Sun Aug 2 09:54:57 CEST 2009

Hi all,

Attached a second attempt at adding the support for LPCM streams in mpeg transport streams.

After some discussions it's made into a separate file which might at some time also host the code for LPCM in DVDs, removing the
decoding of the header from the mpeg demuxer and putting it in the codec.

It is only tested with the following formats:
- 2 channels, 16 bits, 48kHz (my original sample)
- 6 channels, 24 bits, 48kHz (played cropped to stereo on my laptop, thanks to Baptiste for providing the sample)
- 8 channels, 16 bits, 48kHz (it is recognized, but ffplay can't play back because SDL rejects 8 channels)

The following limitations exist:
- Also decodes 16bit to 32bit as the codec apparently can't influence the sample format, and the first packet needs to be decoded
before we know how many bits are stored (at least ffplay didn't make any sense out of anything else)
- 20 bits is not implemented as I don't have a sample or the specs
- channel mapping might be wrong - actually I don't know how to tell the core about it

Pointers for any of the above are appreciated.

BTW, I'm pretty sure the 20/24bit code in pcm_dvd isn't working. It seems to me that it tries to read twice the existing number of

When I'm back home to my DVD collection in about a month I'll check out if I have any 20/24 bit PCM DVDs in there - in the mean
time, samples are appreciated.

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