I’m playing Volumio with my new HiFi Berry, and it sounds good. But when I look at /proc/asound/card1/pcm0p/sub0/hw_params it shows format: S24_LE and rate: 44100. My music is 16 bit, so why is it resampling to 24? Resampling is disabled under Volumio playback settings.

The resampling is for all audio format or only for mp3?

+1 for this wanting to understand what’s going on here.

For me
-16 bit MP3, WAV, AIF comes out as 24 bit
-24bit WAV & AIF comes out as 32 bit.

Also see this topic, it’s the same question for me.

You’re not actually re-sampling here - you’re up-converting the bit depth.

Up-converting the bit depth has zero impact on the sound quality - each sample is just getting padded with extra zeroes. This has no effect at the D/A conversion stage.

This is likely happening because this is what your DAC hardware is requesting of the system on playback.

This seems like a logical explanation to pad with zeros to match with processing elements like DAC.

So what i don’t really understand is 2 things,

  1. 16 bit goes to 24 bit, 24 bit to 32 bit. Why doesn’t 16 bit go to 32 bit too as DAC is 32 bit PCM5122 ?

  2. At what point in the audio path is the bit rate shown on Volumio UI measured ?

Many thanks in advance.