[FFmpeg-devel] Blu Ray drive donation

Ian Caulfield ian.caulfield
Tue Mar 17 10:58:48 CET 2009

2009/3/16 Justin Ruggles <justin.ruggles at gmail.com>:

> Apparently there are some streams that mix regular AC-3 and TrueHD in
> the same substream. ?It seems the TrueHD frame is placed after the AC-3
> frame. ?I'm not sure if it provides additional channels or is a lossless
> version of what's in the AC-3. ?My first guess is that it's the same
> audio encoded twice because TrueHD is an optional codec in Blu-ray, but
> AC-3 is mandatory. ?Maybe it's both..lossless version of 6 channels plus
> extra channels. ?Anyone else know more about this? ?Or better yet, have
> some samples?

I had a sample, although I can't seem to locate it now. It had an AC-3
and a TrueHD version of the same track, encoded as two streams with
different extended_stream_ids but muxed onto the same PID. I did look
at adding support for this, but the current mpegts demuxer relies on
one PID == one stream, so I didn't know how to proceed...


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