[vorbis-dev] speech [was Just to dispel any hopes -- RC3 really low bitrate

[Kevin Marks]

This was discussed a long way back. Basically, the answer was use a 
voice codec for speech, not a music one like Vorbis. GSM or PureVoice 
are available options, EVRC etc are coming.

If you are going to encode speech aggressively with Vorbis, put it 
through a hefty noise gate so all the silences are true silence, as 
otherwise Vorbis will work hard to preserve the nuances of the room 
noise for you.

Based on Monty's comments, are you giving up any attempt to compete with 
QDesign 2 at slow modem rates (20-24 kbits/sec) or fast modem rates 
[34-40 kbits/sec]

On Wednesday, January 2, 2002, at 02:01 AM, Jonathan Walther wrote:

> So what command line options would you recommend for encoding a WAV file
> of voice content, such as a political speech?  I'm looking for the
> smallest file size possible which is still listenable.
>
> On Tue, Jan 01, 2002 at 10:49:05PM -0500, Monty wrote:
>> That's not quite the best way to do it; just -M with no -b will give
>> somewhat better results.  In rc4, -q with -M will be possible, and
>> this will be better yet.  Setting -b and -M to the same value will
>> cause far too much drastic hard limiting of the audio.  You want the
>> codec to be able to 'work ahead' and save up bits in the easy
>> sections; using -b says 'always use 'em'.
>>
>> In any case, it's possible to go under 64kbps 44.1kHz stereo, but I
>> find the results harsh so the encoder is neither tuned for it, nor
>> intended to go lower.  I can provide some examples using the rc4
>> branch if you're curious; the effect is actually mp3proish as the high
>> end gets more and more synthetic sounding, as opposed to the near
>> total falling apart it does now.
>

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