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Russ Stodieck · Posted - Tue Sep 04, 2001 9:56 am

I bring up a .wav file, do a file save as .au format and when I play back the newly saved .au file the pitch or frequency and volume levels are not the same as the original .wav file. These files must sound the same. How do I covert the .wav to .au correctly so both files sound the same during playback?

Thanks,
Russ

Edited by - russ stodieck on 09/04/2001 11:41:59 AM

Syntrillium M.D. · Location: USA

Hello Russ. I think the problem here has to do with a misunderstanding about the formats in question...

WindowsPCM Wave is an uncompressed wave file format. Essentially, what you hear is what you get, everytime.

With the Next/Sun format (.au) this is an 8-bit COMPRESSED format (actually, there are several 8-bit options including a-law and mu-law, g-721, and a 4-bit option) that actually compresses the audio and then decompresses upon playback. Because of this, a file created as an uncompressed wave and then saved as an .AU will not sound the same. In fact, when you save to .AU, a message pops up telling you that you are saving to a 'Lossy Format'...which essentially means to keep a backup copy of your original, uncompressed WinPCM wave file.

---Syntrillium, M.D.