<p>I think I found the issue. One of the device is USB 1.1, and this causes the whole hub to fall down to USB 1.1 to accommodate it. I saw it using <code>lsusb -v</code>.</p>

<p>USB 1.1 has a max bandwidth of 12Mbps, hence the reading I get with <code>lsusb -t</code>. I'll need to either replace the USB 1.1 device for a USB 2.0 device, or plug in a second USB card directly in the motherboard. </p>

CC BY-SA 4.0
2020-04-20T23:13:32.630Z
2020-04-20T23:13:32.630Z
leftcursor
<p>I have two USB devices: a webcam and a microphone.  I can play the webcam's video into VLC and GUVCView. However, I want to use the microphone for another application. The issue is that launching media capture with VLC or GUVCView blocks the microphone.</p>

<p>For instance, running the following before launching VLC/GUVCView:</p>

<pre><code>arecord -vvv -f dat /dev/null
</code></pre>

<p>Shows what the microphone picks up. If I launch VLC first with the following command (webcam is on video0):</p>

<pre><code>vlc v4l2:///dev/video0
</code></pre>

<p>And then monitor the microphone with the previously shown <code>arecord</code> command, I get nothing. It is the same behavior with GUVCView.</p>

<p>Doing the opposite, launching <code>arecord</code> before VLC, however shows the issue. I only get part of the webcam's image (like the few first lines of the image). Dropping the camera resolution shows more lines in the webcam's image.</p>

<p>It looks like I don't have enough USB bandwidth for both the webcam and the microphone. However, typing <code>lsusb -t</code> show that I have USB 2.0, which supports 480Mbps, and that the webcam only pulls 12Mbps.</p>

<video-capture><linux><microphone><usb>
USB Webcam not working with USB Microphone
leftcursor
# USB Webcam not working with USB Microphone

(Asked by: username_0 on 2020-04-14)

I have two USB devices: a webcam and a microphone.  I can play the webcam's video into VLC and GUVCView. However, I want to use the microphone for another application. The issue is that launching media capture with VLC or GUVCView blocks the microphone.
For instance, running the following before launching VLC/GUVCView:
arecord -vvv -f dat /dev/null

Shows what the microphone picks up. If I launch VLC first with the following command (webcam is on video0):
vlc v4l2:///dev/video0

And then monitor the microphone with the previously shown arecord command, I get nothing. It is the same behavior with GUVCView.
Doing the opposite, launching arecord before VLC, however shows the issue. I only get part of the webcam's image (like the few first lines of the image). Dropping the camera resolution shows more lines in the webcam's image.
It looks like I don't have enough USB bandwidth for both the webcam and the microphone. However, typing lsusb -t show that I have USB 2.0, which supports 480Mbps, and that the webcam only pulls 12Mbps.

**Tags:** video-capture, linux, microphone, usb


---

## 1 answers

### Answer by username_0 on 2020-04-20. Score: 0 | Accepted answer

I think I found the issue. One of the device is USB 1.1, and this causes the whole hub to fall down to USB 1.1 to accommodate it. I saw it using `lsusb -v`.

USB 1.1 has a max bandwidth of 12Mbps, hence the reading I get with `lsusb -t`. I'll need to either replace the USB 1.1 device for a USB 2.0 device, or plug in a second USB card directly in the motherboard.


---

