[vorbis] Low sample rates / bit rates

[Michael Smith]

At 08:02 PM 11/21/00 -0800, you wrote:
>    I wrote:
>> >Hey guys. I think Vorbis is pretty cool, but since the current OggEnc
only offers 44.1kHz,
>  Michael Smith wrote:
>> Wrong. Oggenc supports different sample rates correctly. 
>  Oops. My stupidity for not actually trying it. *embarrased blush* Even
so, it's a little
>misleading to have "OggEnc input files must currently be 44.1kHz, 16 bit
stereo WAV files." on the
>help screen. Perhaps it should read something like "Best quality will be
achieved with 44.1kHz, 16
>bit stereo WAV files". I just tried encoding something with the latest
OggEnc, & it's a fair bit
>faster than with Lame. The only advantage it seems that Lame has now, is
that it supports mono
>encoding & OggEnc does not.

I updated the help, I guess I forgot to commit it. I'll do so soon. 
OggEnc also supports (and has for ages - at least since beta2, and possibly
earlier) mono encoding. You should try that too.

>> Last I checked, lame still didn't have updated vorbis support - has this
changed recently? If
>not, it's possibly worse than oggenc at different sample rates. 
>  I don't think it has. It most probably is worse. The compile that I was
using was a prehistoric
>one from - http://doslame.nm.ru/ - run by someone calling themself
"tofikman". But in optimising
>OggEnc specifically for 44.1k, is it likely to reduce quality for other
sample rates compared to
>before optimisation?

>From what you say below, it appears that LAME's support has been updated at
least somewhat, though presumably not to beta3. 
There is no before/after tuning for 44.1kHz - all the stuff has been
designed, tested, and trained on 44.1kHz input.

>> What does -v4 do? I thought lame just ignored all the options when
encoding vorbis. 
>  I actually meant "-V4". Here's what Lame does with the "-V?" switch
(which may have been changed
>recently) -
>* "lame --ogg -V0" => Vorbis mode E
>* "lame --ogg -V1" => Vorbis mode C
>* "lame --ogg -V4" => Vorbis mode B
>* "lame --ogg -V5" => Vorbis mode A
>* V2, V3 - ?... V6-V9 - mode A
>  I think "--ogg" assumes "-v", which in turn assumes "-V4", so Lame
probably runs Vorbis mode B
>by default. And unfortunately, there's no way to call mode D with the
"-V?" switch. From memory
>(this isn't my home computer) Lame takes note of the "--resample", "-mm",
"-a", & "-b" switches,
>as well as some id3 switches, although, a compile of OggLame that I used
previous to that (which
>had no MP3 output) ignored id3 switches. Oh, what does Vorbis call what
MP3 calls "id3"?

Ah. Last time I looked, lame didn't support different modes at all. The
vorbis comment header is broadly equivalent to id3 - feel free to think up
a catchy name if you must have one.

I'd like to get stuff like resampling into oggenc eventually, but I don't
think there's much benefit at this point. However, expect this at some
point in the future.

Michael

ps. It would be nice if you could make your mail client wrap correctly (or
at least less strangely)

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