flac dev - Oct 2008 - Support for CAF in flac command-line?

Thanks for the interest, Michael.

I don't use Ogg, so I'm a little wary that standard FLAC would be  
left out of any Ogg Frog implementation.  But I say that mostly out  
of ignorance.  I have noticed that there seem to be two worlds for  
FLAC, inside Ogg and outside.  It's important to be aware of the fact  
that many hardware devices support the FLAC format directly, without  
the Ogg container/wrapper.  I would want the ability to convert FLAC  
to CAF directly, hopefully without an intermediate Ogg file (since  
I'm talking about file sizes where each is over 4 GB).

QuickTime is a very good suggestion, and gets two platforms supported  
rather than one, as the AudioFile API in CoreAudio would do.   
However, QuickTime tends to be rather limited, and when developers  
run into those limitations, Apple engineers tend to recommend that  
folks turn to CoreAudio for full support.  Also, I really would like  
to support Unix, assuming that there are as many Unix folks using  
FLAC as there are Windows users taking advantage of this underground  
format.

As for the patent question, it's a very smart question, but I think  
as soon as any interested developer looks at the CAF specification  
from Apple, it should be readily apparent what the legal  
ramifications are.  My hunch is that Apple does not want to encumber  
the format, but I'll let their public documents speak for them.  In  
any event, it's a very good issue to be aware of from the start.

Thanks again for the comments, and be sure to keep us informed if you  
do anything.

Brian Willoughby
Sound Consulting


On Oct 12, 2008, at 21:25, Michael Crawford wrote:

On Sun, Oct 12, 2008 at 7:26 PM, Brian Willoughby  
<brianw at sounds.wa.com> wrote:
> Is anyone here potentially up to the task of adding support for CAF
> (the CoreAudio Format) into the flac command-line?  This would
> present minimal difficulty under OSX, due to the presence of the
> CoreAudio API, but the real challenge would be to support CAF on Unix
> and Windows - everywhere that flac is now available.
I expect I could do it as part of my work on Ogg Frog:

http://www.oggfrog.com/free-music-software

In the short term, I would do it by accessing the QuickTime APIs -
which *are* available on Windows, if you install either iTunes or
QuickTime for Windows.  (The iTunes install includes QuickTime.)

In the long term, I could write a codec for it that would be
straightforward to integrate into the flac command-line tool.  That
would allow its use on UNIX.

HOWEVER!

Is the CoreAudio file format or its associated algorithms patented?
QuickTime in general has many patents.

A patent wouldn't stop me from writing the source code, but a binary
couldn't be provided by anyone in a country that recognizes software
patents.

Mike

> Thanks for the interest, Michael.
I hope I really can be of help.
> I don't use Ogg, so I'm a little wary that standard FLAC would be
> left out of any Ogg Frog implementation.
Ogg Frog already supports native FLAC as a player.  Version 1.0 will
only support playing and decoding, but version 1.1 will support
encoding, and I'll be sure to support FLAC with and without Ogg.

I must hasten to point out that I don't offer any downloads yet - the
UI is in a very primitive state.
>  My hunch is that Apple does not want to encumber
> the format, but I'll let their public documents speak for them.  In
> any event, it's a very good issue to be aware of from the start.
I'm afraid AAC (MPEG-4 audio) has many, many patents. Unlike MP3, one
cannot even distribute the binary of an Open Source player.  AAC
stands for Apple Audio Codec - it's their lossy codec.
> Thanks again for the comments, and be sure to keep us informed if you
> do anything.
Of course.

Mike
-- 
Michael David Crawford
mdcrawford at gmail dot com

   Enjoy my art, photography, music and writing at
http://www.geometricvisions.com/
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I will quote from the CAF spec:

"This document is intended for anyone who needs to understand the  
structure of CAF files. You can use the information in this document,  
for example, to write a CAF parser or to extend the types of data  
stored in CAF files. Because CAF files offer many advantages over  
other audio file formats, anyone writing an application for Mac OS X  
that reads or writes audio files should read at least the overview  
chapter to gain an understanding of the features of CAF files. In  
addition, you need the information in this document if you want to use  
CAF files on other platforms.
End users of professional audio software may be interested in this  
document in order to learn more about the capabilities of software  
that supports CAF."

IANAL, but I sure hope Apple wouldn't sue someone who "write[s] a CAF  
parser" or "want[s] to use CAF files on other platforms." 
Hopefully,
the existence of libsndfile support for CAF shows that the format is  
open.

Brian Willoughby
Sound Consulting


On Oct 12, 2008, at 22:27, Michael Crawford wrote:
> My hunch is that Apple does not want to encumber
> the format, but I'll let their public documents speak for them.  In
> any event, it's a very good issue to be aware of from the start.
I'm afraid AAC (MPEG-4 audio) has many, many patents. Unlike MP3, one
cannot even distribute the binary of an Open Source player.  AAC
stands for Apple Audio Codec - it's their lossy codec.

Michael Crawford wrote:
> Unlike MP3, one
> cannot even distribute the binary of an Open Source player.
Even distributing an MP3 software player requires the payment
of license fees:

     http://www.mp3licensing.com/royalty/software.html

Erik
-- 
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Erik de Castro Lopo
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