[PROBLEM] SoX Resampling and Camilla DSP

[H3r0n_M45t3r]

I created parametric eq setup using Camilla DSP. I only modified "Filters" tab content in pipeline editor (only simple biquad peakings and shelf filters), didn't change samplerate, no resampling etc.
When enabling SoX resampling in mpd settings with settings:
-samplerate: 768kHz
-resample (adhere to base frequency)

I expect to end up with:
-44.1kHz files upsampled to 352.8kHz
-48kHz files upsampled to 384kHz

as max samplerate that Camilla DSP can work with is 384kHz.

Instead everything is upsampled to 384kHz which is undesirable in case of 44.1kHz files.

If I configure SoX resampling to samplerate 384kHz; adhere to base frequency, then resampling works correctly with Camilla DSP, and 44.1kHz files are upsampled to 352.8kHz.

Thank you in advance for help.


Edit: Original post had a typo: "-44kHz files upsampled to 384kHz" instead of "-48kHz files upsampled to 384kHz"

[bitlab]

If you reread your own post, you will see that you answered your own question 

[H3r0n_M45t3r]

Why is that?
Max Camilla DSP samplerate is 384kHz, that should result in 384kHz for 48, 96, 192 kHz files, and in 352.8kHz for 44.1 88.2 176.4 kHz files.
If resampling is configured to adhere to base frequency (which in case of files that cause problems is 44.1kHz) then it should result in possible resamples of: 88.2, 176.4, 352.8, 705.6.
Settings used by me in SoX are 384 and 768, which have the same base frequency of 48. But In case of 44.1 files, resampling should adhere to this file's base frequency (if that option is enabled, which it is) to avoid aliasing. Using 384kHz resampling works correctly and produces 352.8 for 44.1 files. But with 768 (still adhering to base frequency!) it ignores the base frequency and force upsamples 44.1 files to 384, introducing aliasing.

[Tim Curtis]

IIRC its because MPD/ALSA device rate detection and correction happens after or in place of the selective resampling operation and thus effectively overrides it. Something like that.