[Vorbis] libvorbis 1.2.3 not generating 96kHz ogg file

[Gregory Maxwell]

On Sat, Jan 9, 2010 at 2:10 PM, CSB <beltoid97 at email.com> wrote:
> Hi,
> I'm trying to get ffmpeg (linked with libvorbis 1.2.3) to generate
> a 96kHz ogg file, but I seem to be limited to 50kHz . The command
> is
> ffmpeg -i t16bit96kHz.wav -acodec libvorbis test.ogg
> and I get the error message
> [libvorbis @ 0x2051460]oggvorbis_encode_init: init_encoder failedError
> while opening codec for output stream #0.0 - maybe incorrect parameters
> such as bit_rate, rate, width or height
>
> I tried specifying different sample rates, and anything >= 50001Hz
> will give that error message.
>
> Is this a bug with libvorbis or is ffmpeg somehow preventing
> me from specifying higher sample rates ?


Libvorbis 'make check' explicitly tests 96000 Hz, and oggenc works
fine on that samplerate for me. I see that ffmpeg is defaulting to
strictly managed bitrate rather than the vorbis VBR default behaviour.
 It seems that managed mode is not supported by libvorbis for high
sampling rates.  This is why it's failing for you.

Managed mode is really only sensible for streaming applications— where
96khz is probably not sensible. If you're not doing realtime streaming
I'd advise against using bitrate management. ...though management
should probably be updated to support 96khz.

In any case, I would _strongly_ recommend against using ffmpeg to
encode vorbis, even with libvorbis, at this time as the limitations of
the ffmpeg ogg muxer will result in an additional 9 to 77 kbit/sec of
container overhead (depending on the mixture of long and short
blocks).