Is the Microphone sample rate set in the registry?

[John Travell]

Folks,

I have a wierd problem with what I perceive to be microphone sampling rate.
If I run 'sound recorder' and record a 3 second test sample, the recorder
window claims that 6 seconds have elapsed, and playback takes 6 seconds with
the recorded sound playing at half speed.
In other words, a normal voice becomes a very low pitched and
incomprehensible groan...

Environment. W2Ksp3. Lucky Star K7VAT M/B Athlon XP+1800 cpu effectively
underclocked at 1100Mhz. Audio h/w is on the VT82C686A chip on the M/B.
Latest drivers make no difference.
If I boot from WinME the sound recorder works correctly, so clearly the
hardware is OK.

An extensive search, both on the PC in question and numerous internet
resources, has failed to reveal where Windows keeps the sampling rate
information.

Does anyone know if the microphone sampling rate is a registry setting ?
If so, any suggestions where to look, and maybe how to decode if it is a
binary value ?


John Travell
john - at - travell - dot - uk - dot - net

 

[Ndi]

If the sampling rate is off, it should have nothing to do with your
microphone, but with the encoder/decoder of the format you use. You should
check the installation of the codecs, perhaps reinstall/upgrade WMP.

If you have 3rd party multimedia software, like disk burning apps,
players, movie players, etc these might have onerwritten the codec with an
"enhanced" version.

Regardless of how you record audio, the software writes the sample rate in
the file and it gets played exactly the same (hardware controls this). Try
various formats and sample rates, it is meaningful if all formats exibit
this behaviour. Also try to use a professional record/play software, as
trial, to see if that software (that should use its own codecs) records
correctly.

Bottom line is that if the sample rate is somehow wrong, correcting it
wouldn't do much good since it should always be the same at playback. Since
hardware doesn't do it (I fail to see how), it's most likely related to
encoding the file (the encoder records at 22000Hz and writes the standard,
44100Hz header. This will make the file play twice the speed). A broken
codec does this tipically.

A good example is one of ATI's MPEG2 codec that thinks my disk has the job
of encoding -I asume- and by overwriting the default codec all MPEG2 data
created on my system is unplayable. This looks similar to your issue.

Try a 3rd party recorder that records to -say- mp3 and use Winamp to play
it. It should sound OK, since mp3 encoders usually come with software and
playback (winamp) comes with its own internal decoding.

First try to use both 44100, 16 bit, stereo to rec/playback. Then try
21000, 16 bit, stereo. If one works and the other doesn't, you have a 99%
chance of a bad PCM codec. Then try 3rd party MP3. If this plays correctly,
the owner of the codec pack mismatches your configuration, it might be the
best time to restore default encoding.

 

[Ndi]

I seem to have missed the direct answer to your question. It isn't stored.
Each program saves a "preferred" setting, but, as SndRec does, it allows you
to set a format when recording a new file. This setting is passed to the
hardware in order to operate recording/playback.

At best, you could set SndRec to default to -say- 44100, 8 bit, mono upon
startup. Even though I think SndRec uses an ini file (not sure).