[vorbis] How to fit Oggs in a specific amount of space?

[Martin Fontaine]

> Well, the point of a quality setting is to select the quality *your
> ears* need to be happy. While doing so, the encoder picks as many bits
> as necessary and as little as possible to maintain the quality you
> selected. It depends entirely on the music that you encode, because VBR
> doesn't "think bitrate" anywhere. About the linearity - no, it is not.
> At least I don't think it is, from what I've seen so far ... ;P

        Well, what I meant was to do both as the same time, the ability of 
determining the space the files will take AND still using a quality 
setting for consistant quality throughout all albums.  The same trick 
is used when movie studios author DVDs, they determine what's the 
highest nominal bitrate they can use to fill the disk depending on 
the length of the movie and extras on the disk.  The way to do it is 
to predict (Analyse the sound or something) how much space the 
file(s) will take to fit the space needed.  Although now I wanna fit 
5 albums on a CD, this will become more important when we get 
portable players, the ability to fit an album in say a 64 Meg card.

        I think I should clarify what I call the "Nominal Deviation" as I 
don't think this is the official term.  For example, at q8 which is a 
nomial bitrate of 256k, A Woman's Worth by Alicia Keys gets an 
average bitrate of 227.1kbs which is 88.7% of the nominal bitrate. 
This is what I refer to as the Nominal Deviation as it is some sort 
of measure of how "Hard to encode" the song is.  The same song 
encoded at q5 (Nom. of 160kbps) gets an average of 148.5kbps which is 
92.8% of the nominal bitrate and encoded at q3 (Nominal bitrate of 
112kbps) gets an average of 106.1 which is 94.7% of nominal.  It 
seems that the higher the quality setting, the lower (compared to 
nominal) the bitrate will be.  Since we are talking about the same 
song, there has to be some sort of consistancy as it's always as hard 
to encode regardless of bitrate.

        So if those 5 albims I encoded at q10 take up 774 Megs, there has to 
be a formula that would tell me what q setting to use to fit in 700 
Megs (Or say 690 just to be safe)

        Isn't there a way to analyse the WAV file(s) and determine the 
nominal deviation (How hard it will be to encode) and then 
calculating the q setting to use depending on the size we want.

+--------------------------------------------------+
|      Martin Fontaine     mfont at videotron.ca      |
+--------------------------------------------------+
| The Braids Bonanza: http://braids.cjb.net        |
| Mel D.'s Good Gifts: http://come.to/meldoane     |
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| "Some people spend their time just running away  |
|  from what's right." -Kele Le Roc                |
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