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7.1 FLAC to Vorbis --> Channel mapping ist totally messed up
McKebapp
post Nov 18 2011, 20:15
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Hi Gals and Guys,

I'm a little lost. I try to encode a 7.1 FLAC File to a 7.1 Vorbis File.
For some strange kind of reason, the mapping of the encoded file is totally messed up.
Front Right is on Center, Right Side on LFE, Right Rear ist Left Rear and so on.

I don't know what I'm doing wrong.

For encoding I use the command line encoder "Oggenc2.87 using aoTuVb6.03".
My settings are: c:\vorbis\oggenc2 -k -m160 -q8 71file.flac.
The resulting 71file.oga plays nicely and is very small. But the channels...

Is there any attribute I can set to prevent a remapping? Or any to force a remapping in a particular order?

I'm sorry, I've been searching this forum for hours, but I didn't find anything useful sad.gif

Thanks in advance,

McK
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lvqcl
post Nov 18 2011, 20:56
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decode to WAV, then encode to Vorbis. Maybe this will help.

Or try this (decode & encode without intermediate wav file):
CODE
flac -d -c 71file.flac | oggenc2 -q8 --ignorelength - -o outfile.ogg
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aufkrawall
post Nov 18 2011, 21:38
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Maybe using Oggenc2.87 using libVorbis v1.3.2 is an option?
The changelog lists up a fix regarding 7.1 channel mapping.
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McKebapp
post Nov 18 2011, 22:31
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QUOTE (lvqcl @ Nov 18 2011, 20:56) *
Or try this (decode & encode without intermediate wav file):
CODE
flac -d -c 71file.flac | oggenc2 -q8 --ignorelength - -o outfile.ogg


Hell Yeah! That did absolutely do the trick!
Could you please explaine a little, what happened?




QUOTE (aufkrawall @ Nov 18 2011, 21:38) *
Maybe using Oggenc2.87 using libVorbis v1.3.2 is an option?
The changelog lists up a fix regarding 7.1 channel mapping.


Yes, thought that, too.
But the libVorbis Version is way older (2010-11-06) than aoTuVb6.03 (2011-05-04).
And aoTuV has also written "multichannel code improved".
So I tried both, and both didn't work at first.


Thank you all very much Guys biggrin.gif
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tuffy
post Nov 19 2011, 05:19
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QUOTE (McKebapp @ Nov 18 2011, 15:31) *
Hell Yeah! That did absolutely do the trick!
Could you please explaine a little, what happened?

"flac -d -c" decodes the FLAC file to Wave file data and sends it to stdout. "oggenc2" takes that Wave data from stdin, understands what order the channels are supposed to be in and then converts them to Vorbis channel order during encoding.

Things got a little messy because Wave 7.1 channel order is:

front left, front right, front center, LFE, back left, back right, side left, side right

while 7.1 Vorbis order is:

front left, front center, front right, side left, side right, back left, back right, LFE

but since FLAC doesn't actually define an assignment for 8 channels, sometimes programs have to wing it.
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