On Sun, 14 May 2006, Kwan Lowe wrote:
>>>>>> wav file plays at a significantly slower pace than what was recorded.
>>>>>> Is this a known problem?
>>>>
>>>> It's not a known-to-me problem. I've _never_ seen Audacity do this. You
>>>> might want to see why it's doing this, and re-record the music.
>>>
>>> I've seen this happen often.. It occurs when the recording is done at a
>>> faster Hz than the playback. WAV is apparently a fixed speed,
>>
>> I don't think so. I've recorded 22.05 kHz and 44.1 kHz WAVs, and converted
>> between them. The file sizes attest that it's not merely a faked sample
>> rate. WAVs may have a limited set of valid rates, though.
>>
> Yes -- I think we're talking about the same thing. A 22.06 KhZ wav file is
> exactly half of a 44.1KhZ wav. How I understand it is that the WAV format
> is just a series of measurements taken at x number of intervals per
> second. It's fixed to what it was recorded at because each data point is
> directly equivalent to a sample point unlike some other formats that
> encode time and other information in the data/stream.
>
> So to change the sample rate of a WAV you'd need to change the header and
> downsample or upsample the data. I.e., if you convert a 22 KhZ to a 44 KhZ
> you double the number of samples programmatically or vice versa.
Or you can change it from 22 to 44 by doubling the speed, like playing a 33
rpm record at 45, which is what I did and what he wants (well, not double,
but same idea). That just changes the "play at this many samples per
second" number in the header. I don't know if that can be any random
number.
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