[ecasound] W64 format conversion correctness

From: Free Lunch <freelunch@email-addr-hidden>
Date: Sat May 21 2005 - 03:11:58 EEST


I have been looking at using W64 to get around the 2 GB file limits
when recording to WAV with ecasound. I would prefer to have automatic
splits with WAV but don't think it is supported.

I ran some tests converting an 8 MB CD format WAV file to W64 and back
to WAV. I then compared the original and new WAV via phase inversion.
 The results were more noisy than I expected. Baudline reported around
15dB at low frequencies.

When I repeat this test using a copy of the original WAV in place of
the W64 converted version, the inverted result appears perfect (no
sound). So I don't think this is a sox issue.

I considered that my AMD64 system might be part of the problem but
received similar results on an Athlon XP. Both systems run Gentoo.

I'm wondering why this conversion isn't perfect and whether it could be?

On a more positive note, ecasound has been working great.

Thank you!


Command history for test cases

"Control case"

cp orig.wav orig.copy.wav
# Phase invert copy of original
sox orig.copy.wav -v -1.0 orig.copy.invert.wav
# Mix original and inverted. Should cancel.
soxmix orig.wav orig.copy.invert.wav orig.copy.invert.mix.wav
# Review result
baudline orig.copy.invert.mix.wav

"Test case"

# Convert original to W64
ecaconvert .w64 orig.wav
# Convert W64 back to WAV
ecaconvert .wav orig.wav.w64
# Mix inverted copy of original with test file
soxmix orig.copy.invert.wav orig.wav.w64.wav orig.wav.w64.mix.wav
# Review result
baudline orig.wav.w64.mix.wav

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Received on Sat May 21 04:15:09 2005

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