sample rates in audio

Sivakatirswami katir at hindu.org
Wed May 17 02:14:14 EDT 2006


Oh my... now wonder it is so confusing... "recordSampleSize" is NOT  
the sample rate...


On May 16, 2006, at 3:15 PM, Stephen Barncard wrote:

> I don't know how rev would store an 11 bit wide word without waste.  
> Computers store info in their nice 8-wide world. It comes down to  
> parts and sanity. There are packing methods to do this - is that's  
> what's happening here?
>
> Try a test. See if there is no difference in file size between  
> using 11 bit and 16 bit wide for  RecordSampleSize


Confirmed, you are so right...

on recordSound
   set the recordsamplesize to 11
   set the recordrate  to 5
   set the recordformat to "wave"
   record sound file gAudioTestPath
end recordSound

12 secs --> 184K

open in QT Pro, get movie props... it shows 16 bit, 8 khz

on recordSound
   set the recordsamplesize to 16
   set the recordrate  to 8
   set the recordformat to "wave"
   record sound file gAudioTestPath
end recordSound

12 secs --> 184K

Same size, same quality...

Sivakatirswami





>
> - which is NOT the sample rate by the way - it is the width of the  
> word describing the voltage of the waveform at that slice of time)
>
> -- the sample rate is actually set by the recordRate property
>
> typical Rev misleading property and command names.   At least  
> there's no DestroyRecording command.
>
> If I used the sound features I would immediately bounce the params  
> from my own well-named commands and call them what I like. Also  
> define with standard rates in constants.
>
> sqb




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