[vorbis] bitrtate peeling and lossless compression

[Larry Fenske]

Keith Wright wrote:

> You have just proven that putting a lossless and a lossy
> compressed file in one directory suffices to accomplish what
> you say you are trying to do.  So Nathan was a bit off on
> the details, but was right to be wondering just exactly what
> is the point.  Why do you not just encode losslessly to
> archive, and re-encode vorbisly to compress?  Is Flac too
> slow?  Do you want an all vorbis system for political or
> aesthetic reasons?  Would you be happy with a GUI interface
> with buttons for both Flac and Vorbis on the same panel?

 From a single file, I want to be able to quickly retrieve music of 
various quality levels, including "perfect" quality (identical to what 
went in to this process).  I should be able to play any of these on the 
same player.

If I have two files in the same directory -- one lossless and one lossy 
-- then the action "play everything in the directory" is not what I 
want.  If the two files are in different directories then the 
association between the two is broken.  A year or ten from now, I'll 
wonder things like "Is this ogg from this version of the flac or a 
different recording?" and "I see this ogg.  Is the flac still around so 
I can safely remove the ogg and still have the data somewhere?"

Also, it seems to me that the lossless compression should be able to 
benefit from the lossy compression so that the lossless+lossy 
combination could be smaller than flac+ogg.

It's not that flac is too slow; more like the flac decompression plus 
vorbis compression combination is too slow.  If it were 100 times as 
fast, then I wouldn't have the feeling that the ogg files were, shall I 
say, as precious since they wouldn't take as much time to produce.

An all ogg system would be nice, not for political, but for aesthetic 
reasons, as mentioned above.

A GUI interface with flac and vorbis buttons?  I think GUIs are much 
overrated.  I have much more flexibility and speed of use from a command 
line.  I can write one-line scripts from the command line to do 
everything I want.  For example, when I digitize audio tapes, I write an 
on-the-fly command line to wait until a digitization is finished, then 
compress, and, if lossless, uncompress and compare, then remove the 
original, then wait for another.  I kick it off once, then keep feeding 
tapes into my player.  If I like the on-the-fly one-line script and it 
gets too long, I copy it to a file.  BTW, I'm not using MicroSoft for 
most of this stuff.

Sorry for the length; I didn't intend to ramble quite so much.

Larry Fenske

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