On Aug 10, 2017, at 5:46 AM, Renatas Lau?adis <rena...@outlook.com> wrote:
> are there any plans for FLAC to implement spatial audio? Or maybe Atmos on 

FLAC is a multichannel audio format supporting up to 8 channels. There are 
advantages to compressing 2 channel (stereo) audio in terms of file size 
savings, but there is no compression advantage to other combinations.

Atmos supports up to 128 channels, 10-channel minimum, so it cannot be directly 
stored in FLAC due to the 8-channel limit. In addition, Atmos presumably has 
it's own lossy compression, so it would be pointless to use a lossless 
conversion for a lossy surround file. Atmos is also proprietary, or at least I 
assume we do not have the option of supporting it anyway.

I do not see any documentation of Spatial - is that a standard format? Is it an 
open format? Is it even intended to be distributed as a separate digital file?

In any event, archival and delivery for mastering of surround audio is 
generally done in individual mono files. Some surround projects are delivered 
on 8-channel digital audio tape with only 6 channels used in the case of 5.1 
surround audio. Beyond 5.1, there must be various methods of delivering audio. 
There might be some advantage with FLAC to combine pairs in surround, such as 
front, side, rear, but otherwise I would say that it's a bad idea to try and 
place more than 2 channels in a single file. The audio frames become too large 
to compress well.

There's a difference between formats used for recording, mixing, and mastering 
versus formats used for delivery of the final product to consumers. Delivery 
formats like Dolby and DTS generally require licensed software compression 
tools, making it difficult to convert to FLAC in any case.

Perhaps you could explain more about what you hope to see?

Brian Willoughby

Flac mailing list

Reply via email to