[pulseaudio-discuss] [PATCH] Re: Why is it still hissing?

Colin Guthrie gmane at colin.guthr.ie
Mon May 30 01:46:56 PDT 2011

'Twas brillig, and David Henningsson at 27/05/11 08:44 did gyre and gimble:
> Colin (or someone else), if you have time, would you give this a test
> spin and apply if it works for you?

I tried this last night.

It was kinda late so perhaps not all the tests are overly valid, but
while it seemed like the code mostly worked, as soon as one channel
dropped completely to 0 (or -inf) things went quite distorted.

I'm not 100% sure that the problem is fixed even without SIMD but I
think it could be mixing problem rather than a volume scaling problem
(the reason I say this is that when running with PULSE_NO_SIMD=1, and
adjusting the volume while playing 5.1, the "bing" noise from
libcanberra seemed distorted (especially when dropping a channel to 0).
It seems the sound plays OK generally, even at zero, so I suspect this
one is mixing based.

Back to the original problem, here is an audacity file that I recoded
from the monitor:

Channel 1 (FL) was 0, Channel 2 (FR) was quite low but > 0, Channel 3
(RR I think) was medium and the rest were PA_VOLUME_NORM.

This maybe helps? As you can (hopefully) hear, it's generally fuzzy all



Colin Guthrie

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