> I have briefly tried the "--voice" mode and the "normal" mode when
> encoding a purely voice signal (with background noise) at 8kbps, and
> have been very impressed with the difference. I would like to compress
> the signal more... but 8 is as low as it goes.
>
> The "nomal" mode renders the voice absolutely unintelligible (I assume
> the encoder tries too hard to preserve the background).
>
> The "--voice" mode actually seems to reduce the background garbage
> (noise) where there is no speech, and to also concentrate on the speech
> when it is present.
>
> I have looked at the spectrogram for each, and there is a BIG
> difference.
>
> My question (after all this guff) is "does LAME perform any smarts (like
> looking for particular frequency domain patterns), and if so, what?"
>
> I have read most of the past articles on "--voice" but they don't tell
> me all I wish to know. I am also starting with a 11K/samples per sec
> file (mono) and having to up-sample it to 44.1K before I can process it.
> Has anyone considered allowing different input sample rates (ie: the
> standard 16, 22.05, 24, 32, 48) as well as 44.1 ?
>
I first wrote the voice mode, mainly by using some supposition about the
signal and a lot of listening tests. You can read what was done at the
beginning by this option here:
http://www.multimania.com/bouvigne/lame/voice.html
Because of a lack of time, and the lack of good filtereing solution at this
time in Lame, I only tuned it for 44.1kHz files.
But now, Robert introduced the presets in Lame, including --preset voice,
and Lame got some good filters. So I think that "--preset voice" is now
doing the same thing as --voice, and can be used for any sampling rate, but
I'd like Robert confirmation to know if the behaviour is the same
as --voice.
If it's doing the same, I'd suggest you to stop using --voice and start
using --preset voice instead.
I personnaly think that now the --voice switch should be removed, as there
is --preset voice.
Regards,
--
Gabriel Bouvigne - France
[EMAIL PROTECTED]
icq: 12138873
MP3' Tech: www.mp3-tech.org
--
MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
