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Full Version: Creating Ogg-Flac with >8 channels
Hydrogenaudio Forums > Lossless Audio Compression > FLAC
michael-hyd
I am trring to create Flac compressed audio in an Ogg envelope.

Naïvely I tried:

 $ flac --ogg -o out.oga nine-channel.wav
nine-channel.wav: ERROR: unsupported number of channels 9

but I thought the Ogg envelope could carry 256 Flac channels??
. (I know native Flac only does 8.)

Even on less than 9 I get

 $ flac --ogg -o our.oga four-channel.wav
 four-channel.wav: ERROR: WAVEFORMATEXTENSIBLE chunk with unsupported channel
 mask=0x0000

Can I over-ride the channel mask? I am (for the moment) just trying to archive
my files (Flac compressed) in an Ogg envelope.

(Sorry cannot see any help in the Flac documentation (lots on changing the metadata _once_
I have my file ...!) or on Web searches. Perhaps I should be using another tool to create Ogg??)
tuffy
The FLAC format, no matter what container it is stored in, doesn't support more than 8 channel audio. I believe the Ogg Vorbis format supports up to 256 channels, but that's a property of the Vorbis codec and doesn't have anything to do with the Ogg container it is stored in. But short of a major overhaul to the FLAC format itself (adding more bits to the streaminfo and frame headers, in particular), there's simply no way for it to handle such a stream.
jcoalson
QUOTE(michael-hyd @ Feb 27 2008, 05:41) *
but I thought the Ogg envelope could carry 256 Flac channels??
. (I know native Flac only does 8.)
to do that you need to multiplex multiple flac streams in ogg. the command-line encoder doesn't do that and there's no standard for channel assigment.

QUOTE(michael-hyd @ Feb 27 2008, 05:41) *
$ flac --ogg -o our.oga four-channel.wav
four-channel.wav: ERROR: WAVEFORMATEXTENSIBLE chunk with unsupported channel
mask=0x0000

Can I over-ride the channel mask? I am (for the moment) just trying to archive
my files (Flac compressed) in an Ogg envelope.
if the channel order matches the flac order or you don't care about the channel assignment you can add '--channel-map=none' to your flac command line.
michael-hyd
QUOTE(jcoalson @ Feb 27 2008, 12:43) *

to do that you need to multiplex multiple flac streams in ogg. the command-line encoder doesn't do that and there's no standard for channel assigment.


I'm happy to settle for my "channel order matches the flac order" (for today). I.e. no channel assignment.

If so, is there a way to multiplex 'n' channels together as Flac compressed
audio in an Ogg envelope, with 8<n<257 ?

michael-hyd

(And thanks for "--channel-map=none", missed that somewhere in the spec.)


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