Audio quality

Submitted by hurroz@cardina… on #1

Hi Michael,

I'm running the MIMO usb display and a Logitech C525 webcam and the video part for both devices is great. But when I use the mic on the webcam to do an AV recording the audio is just awful: 1) out-of-sync w/video, 2) gaps, 3) stops working after a few seconds. I'm using just the standard windows camera app to make recordings. I did try the webcam directly connected to the PC and audio worked just fine.

My config is pi3 running the pro version of the hub, and I have the pi3 and my laptop on the same gigabit switch, and measured 95 Mbits/sec between them w/iperf3.

I know a bit about the complications of iso USB, so I'm wondering whether I should expect to have decent audio quality, and if so, can you recommend a webcam that would work ok?

Thanks, Hector

Submitted by Michael on Fri, 2019/11/15 - 09:34

#2

Can you update your server to the latest 4.0.6 and the client to the latest 4.9.4 and try it again. I made some performance fixes about 1 hour ago. See if it works ok. Remember the pi3b+ pushes all data through a single USB port (including network!) so get a pi4 if you can as it will be much better

Submitted by hurroz@cardina… on Fri, 2019/11/15 - 10:37

#3

I did just update to 4.9.4 and 4.0.6 and the audio is still pretty bad (maybe a small improvement). Found the stats chart and it's pretty much a flat line around 1 msec, which seems like reasonable latency. I'll look around for a pi4 and test with that as well.

Submitted by hurroz@cardina… on Tue, 2019/11/19 - 06:09

#4

Just tried with the pi4, which raised throughput to 945 Mbit/sec from about 95 for pi3 so that was good. But the audio didn't improve at all. Do you know of anyone that's tried successfully to record audio and video over a regular webcam? Thanks!

Submitted by Michael on Tue, 2019/11/19 - 09:49

#5

If you plug the webcam into the pi3 and the mimo into the pi4, does that resolve the audio issue?

Submitted by hurroz@cardina… on Tue, 2019/11/19 - 14:22

#6

No, I've been running just with the webcam, to take the mimo out of the equation.

Submitted by hurroz@cardina… on Tue, 2019/11/19 - 14:39

#7

Just to clarify... mimo by itself works fine on both pi3 and 4. Mimo also works fine alongside the webcam. When I run the webcam by itself (no mimo) the video is good but the audio is bad for both pi3 and pi4.

Submitted by Michael on Wed, 2019/11/20 - 02:54

#8

Ive been testing with a logitech C920 previously and that seemed to work with audio

Submitted by hurroz@cardina… on Wed, 2019/11/20 - 09:35

#9

Ok, thanks Michael, appreciate the quick responses.