[vorbis] encoding bitrates, different machines...

Hugo van der Merwe s13361562 at bach.sun.ac.za
Thu Apr 11 06:42:27 PDT 2002

> My guess is your bitrate varience has nothing to do with vorbis, its
> probably in the ripping, files can vary greatly depending on how you rip
> them, if its a crappier rip you'll most likely see higher bit rates.

It was cdparanoia. I don't believe ripping differences cannot account
for a 10% difference in encoding bitrate.

Bitrates on one of the CD's ripped:

et1: 116 120 121 125 123 118 121 122 116 120 127
set2: 129 124 124 123 123 127 125 125 130 124 126

That is a significant difference. It does not matter too much, really, 
it's just very very curious. Thus my question being "does that second 
set look like a -b128 set?" Does one get that kind of variance with the 
-b switch? If yes, then I think that must be the reason.

So we can end this thread yes, unless someone can answer me that
question with a simple yes or no? (I'll encode my next CD both ways to
get some stats of my own.)

All 6 that I double encoded (yea, there's 6. hehe.) have the second set
between 119 and 130, (with only two less than 122). The first set ranges
from 96 to 128. That 96kbit is track 10 (Biscuit) on Portishead's
"Dummy". And it's nominal bitrate is 128031, i.e. -q 4, I believe. 
(Quite amazing.) In the second set, that track is
"bitrate_average=128422", thus I'm quite sure that must have been -b.

<tagplug> This thread could have been avoided with an "encoder flags"
tag.  If that tag isn't going to be official, at least what was the
final conclusion as to the best "format" and name for the tag? I think I
will hack that into the encoder I'm using. </tagplug>

Thanks all,
Hugo van der Merwe

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