[vorbis] Very low bitrate encoding

Christophe Leske leske at online.de
Thu Dec 5 00:56:13 PST 2002



> > > How do i encode files at a lower bitrate than the 
> apparently fixed 
> > > 45Kbit/s?
> > That would be the clearly documented options --resample and
> > --downmix (the latter mixes stereo down to mono streams, the 
> > former does sample rate conversions). 

Hello Michael, 

i tried to get a better set of docs. All i got so far are the man pages
that come with the line encoding tools.

Could someone point me to a more elaborate set of docs reg. Vorbis
encoding options? I know what ABR, VBR and CBR means.

<p>I also finally figured out the lower bitrate modes (i indeed have to
resample the source file prior to encoding). I was mistakenly assuming
that the source file has to be at the highest quality in order to
achieve best results, even with CBR.

So now i got down to 12Kbit/s for a file which is resampled to 11Khz but
can´t get no lower. 
I am using 

oggenc --managed --bitrate=12 --resample 11025 MySample.wav

There seems to be a link between the sampling frequency of a file and
its minimum encoding bitrate. For a WAV file in 44Khz, i couldn´t get
any lower than 45 Kbit/s, for 11025 i can´t get lower than 12KBit/s.

What´s the rule here? A minimum of at least 1 KBit/s for any 1KHz
smapling frequency?

And yes, i want those shitty sounds for streaming.

Thanks for any help, 
Christophe Leske

<p><p><p>--- >8 ----
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