[pulseaudio-tickets] [Bug 98863] USB audio gives continous heavily distorted sound (random bug) (Alesis core 1)

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=98863

--- Comment #3 from Tanu Kaskinen <tanuk at iki.fi> ---
I don't think it's a clock drift issue. Pulseaudio runs at the sound card rate.
When the system clock is used, the usage is adapted to any differences compared
to the sound card clock.

The audio may become corrupted if pulseaudio writes too close to the point in
memory where the hardware is reading. (An aside: I don't understand the
mechanism of that - I would understand a single glitch, but I don't understand
how the audio can become permanently corrupted, and the resulting distortion is
weird.) I don't know if you have this problem, but "metallic" sounds similar to
what I've experienced on an internal HDA card long time ago.

When this happens, you could record from the sink's monitor source to verify
that the recorded audio is clean. If it's clean, the distortion happens in
lower layers of the audio stack. Here's the command to use (all on one line):

parecord --device=alsa_output.usb-Alesis_Core_1-00-C1.analog-stereo.monitor
--fix-rate --fix-format --fix-channels > test.wav

(I got the device name from the "pactl list" output in your other bug, 99112.)

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/pulseaudio-bugs/attachments/20161221/46ae0f65/attachment.html>