[Tfug] audio formats and programs

[Ammon Lauritzen]

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t takahashi wrote:
> for recording speech and lq music, i am using rec from the sox package
> with default options and a .ogg filename.  the file program says "Ogg
> data, Vorbis audio, mono, 8000 Hz, ~22400 bps, created by: Xiph.Org
> libVorbis I (1.1.0 RC1)".
> 
> i tried cvs, gsm, vms, ogg, and wav.  ogg and wav were good.  gsm was
> small and good but reverbed sibilants.  ogg was fairly small and i
> know it's standard.

Just a note of clarification on terminology. Ogg is a container format,
not an audio codec. What you are creating is Vorbis-encoded audio
wrapped in an ogg file.

It makes perfect sense that wav would sound good, it is uncompressed. If
you have the hd space and the time to spare, you can always record as
wav and then encode into whatever you want. If you are going to be
editing the files, this is probably best. That way you don't introduce
loss from multiple lossy re-compressions.

Vorbis is the best general-purpose audio codec out there, but if you are
dealing with users outside of the open source community, there is a
possibility that they won't have support to play the files. WinAmp has
Ogg Vorbis support, but Windows Media Player most certainly does not
(users have to hunt down and install Ogg DS filters). I also know that
iTunes used to have problems with not including vorbis support by
default, but this could have changed by now.

The most standard audio codec out there would be the ubiquitous (if
moderately evil) mp3. For maximum coverage, use lame to turn your wav's
into mp3 after editing. Of course, mp3 is lower quality than vorbis, so
you'll wind up with larger files in order to reach the same level of
quality.

> i like the quality, but can i do better for size without sacrificing
> standardness?

The good people at xiph.org have also put out another audio codec called
Speex (speex.org). It is designed specifically for low-bitrate encoding
of speech.

I have not, however, actually played with it much.

You would probably lose a good bit of distribution capability by using
the codec, but you would be advancing the cause and stuff ;)

> for editing i am using audacity, which is clunky but fast.

Audacity is great. It's probably the best open source audio editing
application out there.

Again, if you're editing the files, you want to work with uncompressed
files and then encode into something else when all is said and done.

> for sound system i have not bothered trying alsa yet, and i run kde. 
> i will try alsa and quit kde in the future.

ALSA is the standard sound system for the 2.6 line of kernels. It is
bigger than KDE and whatever sound system they may have originally
developed. Any vaguely modern application should include ALSA support
and you really should make the change. It is _much_ nicer than OSS or
trying to deal with ESD and other such more 'proprietary' sound servers.
Is ESD the KDE thingy? Hrm... I forget.

> did i settle on what most people do?

Pretty much ;)

Ammon

- --
Ammon Lauritzen
http://simud.org
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