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IMA ADPCM encoding
post Oct 21 2005, 04:52
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Hi, I recently acquired a cheap chinese MP3 Player with voice recording/encoding capability.

The max voice quality you can get from this is "IMA ADPCM 16bit 32kbps mono".

I downloaded some voice encodings from the player and opened them with Adobe Audition, edited useless parts and saved as the same format.

There is supposedly a re-encoding process going on, but I can´t notice any quality degradation. I really don´t want to save to plain PCM because, correct me if I´m wrong, the files would be 4 times bigger (I already tried with approximately 4x size increase).

What would you do to preserve as much quality as possible without increasing the size (I mean keeping it around the same bitrate)?


Edit: it was actually 32kbps

This post has been edited by Megaman: Oct 23 2005, 01:40

No se porqué
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y me sentí mejor
pero aquí estoy
tan solo en la vida
que mejor me voy
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post Oct 31 2005, 14:26
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If you crop a .jpeg file, you'll have to recompress. You'll lose quality. On the other hand, if you crop a 255 colour .gif file, you still have to recompress, but you won't lose quality.

ADPCM is a bit like .gif; quantization will be lossy but the storage is lossless.

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