flac dev - Mar 2005 - Re: More than 8 channels possible?

Hello,

First, thanks a lot for FLAC. 

A few questions. Apologies if this is not the right forum or if these
questions have come up before; the SourceForge archive search didn't
turn up anything.

1. Would it be possible for FLAC to support more than 8 channels?
2. If (1) is not desirable because it would break compatibility or some
   such, then is it possible to build a local copy supporting more
   channels by simply increasing FLAC__MAX_CHANNELS in 
   include/FLAC/format.h?

Either of these would greatly help in reducing the storage
requirements for recording sessions.

As I am not subscribed to the list a Cc: would be appreciated.

Thanks again.

Pascal.

Are there any recording applications which create files with more than 8  
channels?  For that matter, are there any recording applications which create  
files with more than 2 channels?

I do a great deal of live multi-track recording.  Every tool I use creates  
mono recordings.  At most, I combine microphone pairs or stereo electronics  
channels into stereo files after recording.  Then, when backing up, I use FLAC  
to compress the mono and stereo files.  My recording software already organizes
the files for one session into a directory, so the FLAC files live in that  
directory, too.

One way to save space is to use the "--no-padding" option.  Apart from
padding, there is very little overhead in a FLAC file.  A theoretical  
16-channel FLAC file would not take any more space that 16 or fewer mono/stereo
FLAC files, at least not if you combine related channels into stereo files.

How do you know what the storage requirements would be reduced?  The most  
savings comes from inter-channel correlation.  I doubt you'll really ever
have
more than four channels that actually have real correction in the audio.

NOTE: Adding support for more than 8 channels would increase the FLAC overhead  
by increasing the size of the header!

Brian Willoughby
Sound Consulting


Begin forwarded message:

Hello,

1. Would it be possible for FLAC to support more than 8 channels?
2. If (1) is not desirable because it would break compatibility or some
   such, then is it possible to build a local copy supporting more
   channels by simply increasing FLAC__MAX_CHANNELS in
   include/FLAC/format.h?

Either of these would greatly help in reducing the storage
requirements for recording sessions.

Thanks again.

Pascal.

31/03/05 17:16, Brian Willoughby wrote:

[snip]
> I do a great deal of live multi-track recording.  Every tool I use creates
> mono recordings.  At most, I combine microphone pairs or stereo electronics
> channels into stereo files after recording.  Then, when backing up, I use
FLAC
> to compress the mono and stereo files.  My recording software already
organizes
> the files for one session into a directory, so the FLAC files live in that
> directory, too.
Sometimes it's more convenient to store a 10 channel recording as a 10
channel file, rather than as 10 seperate files wrapped in a container
format.

[snip]
> How do you know what the storage requirements would be reduced?  The most  
> savings comes from inter-channel correlation.  
Didn't know that.
> I doubt you'll really ever have more than four channels that
> actually have real correction in the audio.
No, probably not. Will have to experiment and see.

Thanks,
Pascal.