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Topic: Creating Ogg-Flac with >8 channels (Read 5342 times) previous topic - next topic
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Creating Ogg-Flac with >8 channels

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??)

Creating Ogg-Flac with >8 channels

Reply #1 –
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.

Creating Ogg-Flac with >8 channels

Reply #2 –
Quote from: michael-hyd on
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 from: michael-hyd on
$ 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.

Creating Ogg-Flac with >8 channels

Reply #3 –
Quote from: jcoalson on
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.)