[Flac-dev] Should FLAC join Xiph?

[Josh Coalson]

--- Joshua Haberman <joshua at haberman.com> wrote:
> * Josh Coalson (xflac at yahoo.com) wrote:
> > I'm kind of swamped today so I'll answer what I can get
> > away with until tonight:
> > 
> > --- Joshua Haberman <joshua at haberman.com> wrote:
> > > The most interesting questions to me are ones you didn't address:
> > > 
> > > 1. Will Ogg FLAC become the default manifestation of the FLAC
> codec?
> > > If not, why not?  What does Ogg not offer that makes it worth
> having
> > > two different file formats of the same codec floating around?
> > 
> > I'm hesitant to make that decision myself, I'd rather let
> > users converge on something.
> 
> You make the decision for 99% of users just by the defaults you write
> into the software.
> 
> Even as a fairly informed user, I am unclear on the differences and
> interactions between:
> 
> - Ogg FLAC vs. FLAC
> - id3 vs. vorbiscomment

I'll answer but keep it short just in case you're asking
rhetorically:

> Is Ogg flac literally a FLAC file verbatim with extra framing?

Yes, Ogg FLAC is FLAC where each metadata block and frame is
treated as a packet and fed into Ogg.

>Is it possible to have id3 tags in an Ogg FLAC file?

No, I believe Ogg disallows id3, i.e. compliant apps are not
require to support them.

> Is it possible to have
> both vorbiscomment and id3 tags in the same file?

In the same raw FLAC file, yes (raw FLAC is neutral to id3),
but Ogg FLAC, no.

> If so, which is
> designed to take precedence (ie. what will libFLAC give to the
> application?)  Can libFLAC always read any permutation of these?

libFLAC does not know about id3, it only reads Vorbis (it does
know how to skip over id3v2 tags though).  No compliant FLAC
implementation is required to support id3 but it may if it wants
to.  The plugins currently do it for convenience by merging all
existing tags together, Vorbis comments with highest priority,
then id3v2, then id3v1.

> Above all, why do I need so much choice?  :-)
> 
> I think it would be good to have some sort of standardization or
> recommendation on what form audio data compressed by FLAC should
> take.
> This doesn't have to mean taking away options from the user, just
> crafting the defaults so that users who aren't tweaking things will
> find
> that everything just works.  The user shouldn't have to care if their
> comments are in id3 or vorbiscomment format.  Pick the one that is
> better, and depricate the other (continue to support reading it for
> a while but stop writing it, make it easy to convert one into the
> other, etc.)

If I started over from the beginning that's what I would do.
Vorbis comments are relatively new (this year I think).  I
picked up on Ogg after the raw FLAC format was done.  I haven't
dictated a standard, but by your measuring stick of the easiest
path through the tools, this is what it has evolved to with my
prodding:

Tagging: libFLAC and flac (the command-line encoder) only support
Vorbis comments.

Format: by default flac encodes to raw FLAC.  If you go out of
your way with --ogg you can get Ogg FLAC.  The standard that is
likely to persist is that raw FLAC is used to store audio only
(usually CDs or taped shows), but when you want to stream/route/mux
it through Ogg tools, then Ogg FLAC fits great.

Josh


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