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#143210 - 14/02/2003 07:14 Compress but still not affect pitch.
mvigneau
member

Registered: 12/08/2002
Posts: 179
Loc: Manchester, NH
On my Creative Nomade Jukebox, It has the ability to compress a song/speech in to a shorter time, but not affect the pitch. This is useful to me when I listen to books on tape. Have you heard of a similar feature for the Rio? Probably not, so I just thought I'd ask if you had heard of
anything.

Thanks.

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#143211 - 14/02/2003 09:46 Re: Compress but still not affect pitch. [Re: mvigneau]
TheAmigo
enthusiast

Registered: 14/09/2000
Posts: 363
I remember this coming up on a different forum that I read. I'd asked how the math behind it works and someone posted a step by step on how to do it. I thought it seemed simple enough until I asked about one of the steps. Turns out the math behind one of those "simple sounding" steps was over my head. So, I still don't know how its done.
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--The Amigo

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#143212 - 14/02/2003 11:20 Re: Compress but still not affect pitch. [Re: TheAmigo]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
Yup, to do that kind of audio processing requires a lot of calculus, I'm told.

Back to the original question:

Time-domain processing of audio data is something best left to more powerful chips with an FPU (such as the one on your PC). The Rio Car player doesn't have this feature, but it doesn't need to have it. Instead, do the time-processing on the file ahead of time, before you send the file to the player: Open your audio book file in CoolEdit (or some similar application), compress the time, and save it.

I think you can even open/save directly to/from MP3 format in most of the more recent versions of the audio applications, so you don't necessarily need it to be a WAV file. This will cause a slight degradation of the sound quality, but it shouldn't be a very noticeable degradation for something like an audio book. The time-domain processing will degrade the audio a bit, too, so it's not a big deal to decompress/recompress the MP3 in that case.
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Tony Fabris

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#143213 - 14/02/2003 11:24 Re: Compress but still not affect pitch. [Re: mvigneau]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
What, you don't like listening to Alvin and the Chipmunks read Absalom, Absalom?
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Bitt Faulk

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