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Topic: Reason for "washy" artifacts when using MQ setting in SoX? (Read 825 times) previous topic - next topic

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Reason for "washy" artifacts when using MQ setting in SoX?
I was using SoX's mq resample method with Pulseaudio since it is very low on CPU but would not longer stand its "washy" artifacts so I changed to Speex float 10 even though it is very tough on the CPU. Is anyone knowledgable able to explain how this setting can create this artifacts that I usually associate with low bitrate lossy audio? Regards.

  • bandpass
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Re: Reason for "washy" artifacts when using MQ setting in SoX?
Reply #1
Can you provide a short input audio sample, a sox  command line, and a speex command line that demonstrate the problem?

  • eric.w
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Re: Reason for "washy" artifacts when using MQ setting in SoX?
Reply #2
What are the input and output sample rates when you hear the washy artifact?
Can you reproduce it with command line sox? e.g a sox command line using "medium" quality you can start with is:
  sox in.wav out.wav rate -m 44100
replace 44100 with the desired output rate.

Re: Reason for "washy" artifacts when using MQ setting in SoX?
Reply #3
Hi guys. I the output sample rate is 192000 and the settings I use is soxr-mq in Pulseaudio. That is all the information I can give you about the settings, unfortunately. The artifacts are subtle but occur with high frequency sounds like hi-hats and other cymbals.

  • bandpass
  • [*][*][*][*]
Re: Reason for "washy" artifacts when using MQ setting in SoX?
Reply #4
Hi guys. I the output sample rate is 192000 and the settings I use is soxr-mq in Pulseaudio. That is all the information I can give you about the settings, unfortunately. The artifacts are subtle but occur with high frequency sounds like hi-hats and other cymbals.
Does the output of
Code: [Select]
pulseaudio --dump-resample-methods
include soxr-mq?  If not then PA will ignore the request to use it and use a low-quality default resampler instead.

Are you using ubuntu (or similar)? If so, there is a bug here, requesting that this should be fixed:
https://bugs.launchpad.net/ubuntu/+source/libsoxr/+bug/1702558

Re: Reason for "washy" artifacts when using MQ setting in SoX?
Reply #5
bandpass: Thank you for your reply. I sometimes use Ubuntu but mostly Void and OpenMandriva when I listen to music and I haven't checked them yet. I didn't know that Ubuntu doesn't include soxr. Strange.

Re: Reason for "washy" artifacts when using MQ setting in SoX?
Reply #6
Unfortunately it was reported earlier this year and wasn't fixed in 17.10. Hopefully it will be moved to main or fixed in another way before 18.04 LTS.