[vorbis] Questions about libvorbisenc

Michael Smith msmith at labyrinth.net.au
Wed Feb 20 05:08:24 PST 2002



At 11:50 AM 2/20/02 +0100, you wrote:
>Hi all,
>
>I am just coming in the mailing list.... ;-)
>
>I'm working on an Ripper/Encoder for GNUstep.
>At first sight, libvorbisogg seems to be the library that I needed.

This is a bit confusing - there are two main libraries, libogg, and 
libvorbis. They're seperate and independent. I don't know what exactly
you mean by 'libvorbisogg'.

>The problem for me is documentation. 

Yes, the documentation is lacking - we have limited resources.

>So I have a few question about this library : 
>- in order to init an encoding process, we need to provide channels. Well,
>what does is mean ?

The number of channels in your input audio - i.e. 1 for mono, 2 for stereo,
etc.

>- in order to init an encoding process, we need to provide rate ... What is
>this rate in comparison with bitrate ?
>is it 48khz ? so I have to put 48 ?

Sampling rate. For CD audio, this is 44100. 48000 is another fairly common
value. Whatever you're getting the audio from (a wav file, for example)
will have this information. It's independent of bitrate, though obviously
a higher sampling rate means more information, which means a higher
bitrate. Values are in Hertz (Hz).

>
>- I would like to get the real time rate of encoding  : Is it possible with
>libvorbisogg ?

libvorbis will just encode the data for you - if you want to find out
how fast it is encoding, you have to track that information seperately
(as oggenc does, for example).

>
>And finally, is there any very simple example using libvorbisenc ?

In the source tree, look at vorbis/example/encoder_example.c - that's
a simple and minimal example (though it doesn't show how to do
managed bitrates, you needn't bother with that for a first version).

<p>Michael

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