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MPD interrupted by wifi driver on pi zero W ?
#1
Hi everyone, I'm using a RPi zero W with an Allo miniboss DAC. It's working very well overall but I get problems with upsampled audio (whether done on my computer player or locally on moode), which I'd like to do more due to the DAC only deactivating its processing at 384 KHz. What happens is that I generally get garbled audio and pauses at the start of tracks, and then it works well once a track is finally launched.

I know that the RPi ZW has a pretty lousy CPU and that's its mostly to blame, but I looked a bit more into this today, and it looks like there is enough headroom for the CPU to do the upsampling, as the mpd utilization once the song is launched is around 40-50%. What seems to be happening is that the wifi driver (kworker/u2:2-brcmf_wq/mmc1:0001:1 AND irq/86-mmc1) hogs the CPU when the track is being received all at once at the start. This also explains perfectly why it's garbled at the start but is fine once the data has been received.

Given these elements, is there anything that would be possible to try to solve this, such as reducing wifi CPU priority, capping network speeds or forcing moode to receive parts of the tracks little by little so that I don't get this spike at the start ? I haven't found any options in my player to do so (Audirvana).
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#2
This is a confusing post, when you say your player is Audirvana are you playing from Audirvana to Moode over UPnP?
If you're sending 24/384 over UPnP then you'll need at least a 20Mbps sustained receive rate on the Zero's WiFi to keep up (you're on the edge there with the Zero), the Pi Zero's CPU and WiFi is pretty weak so there's not a lot of room to keep up with buffering and sustained playback.

If you're not using UPnP and you're trying to resample to 24/384 on the Pi using SoX then the Pi Zero's CPU is simply not upto that.

Relax, you're not going achieve high-end audiophilia with a $40 DAC hat so just play at the native sample rate.
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#3
oops!
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bob
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