[FFmpeg-devel] Blu Ray drive donation

Justin Ruggles justin.ruggles
Mon Mar 16 23:34:56 CET 2009

Carl Eugen Hoyos wrote:
> Kostya <kostya.shishkov <at> gmail.com> writes:
>> * VC-1 (interlaced support missing. And I from the streams I've seen it
>> requires implementing interlaced fields support. Should be a good GSoC task)
> The task is still missing a mentor...
> [...]
>> * EAC3 (almost? there)
>> * Dolby TrueHD (should be fine)
> IIRC, there a some streams that don't play. (EAC3 or TrueHD mixed with something
> else in the same substream?)

AC-3 mixed with E-AC-3 in the same stream decodes with lavc, but the
E-AC-3 part with the extra channels is ignored.  I have only ever seen
one sample of this, and it's a Dolby test stream.

E-AC-3 using spectral extension is not supported yet (I just haven't had
the motivation to clean up the patch).  I've only come across 2 samples
which use this, and they are both from HD-DVDs.

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?


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