Icecast - Aug 2004 - vorbis_encode_init() bitrate arguments - offtopic

Hi,

It's a bit offtopic for this list, but you might be able to help. For 
libvorbis rc3, what is the correct bitrate parametrization for the call 
vorbis_encode_init()?

For rc2, it worked calling it the following way:

vorbis_encode_init( &vorbisInfo,
                     2,                     // two channels
                     44100,                 // 44.1kHz
                     -1,
                     96000,                 // 96kb/s
                     -1 );

And this produced an Ogg Vorbis stream of about 80 kbps on average.

But in rc3, the above call produces a circa 240 kbps Ogg Vorbis stream 
(as reported by xmms). I tried putting 96000 in place of the -1 values, 
and also putting 96 instread of 96000, but no luck.

Any hints would be greatly apprieciated.

<p>Akos

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Michael,
> See the examples. If you initialise a managed mode (which this is), you
> MUST use vorbis_bitrate_addblock() and vorbis_bitrate_flushpacket(). 
Thanks for the tip. I added the calls, and it works now.
> You SHOULD also give an option to set min/max, since they're now used,
> and to use a VBR mode rather than the managed modes here.
But when streaming, IMHO it is _very_ essential to be able to specify a 
maximum bitrate. I guess I can't use VBR mode then, can I?

Another offtopic question: what vorbis comments are 'supported' or 
'valid'? I see in the examples:

vorbis_comment_add_tag(&vc,"ENCODER","encoder_example.c");

but what other meta-info? Like artist, etc?

<p>Akos

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At 09:49 AM 2/20/02 +0100, you wrote:
>Hi,
>
>It's a bit offtopic for this list, but you might be able to help. For 
>libvorbis rc3, what is the correct bitrate parametrization for the call 
>vorbis_encode_init()?
>
>For rc2, it worked calling it the following way:
>
>vorbis_encode_init( &vorbisInfo,
>                     2,                     // two channels
>                     44100,                 // 44.1kHz
>                     -1,
>                     96000,                 // 96kb/s
>                     -1 );
>
>And this produced an Ogg Vorbis stream of about 80 kbps on average.
>
>But in rc3, the above call produces a circa 240 kbps Ogg Vorbis stream 
>(as reported by xmms). I tried putting 96000 in place of the -1 values, 
>and also putting 96 instread of 96000, but no luck.
>
>Any hints would be greatly apprieciated.
See the examples. If you initialise a managed mode (which this is), you
MUST use vorbis_bitrate_addblock() and vorbis_bitrate_flushpacket(). 

You SHOULD also give an option to set min/max, since they're now used,
and to use a VBR mode rather than the managed modes here.

Michael

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