doc: refer to video-companion for sys-usb webcam

salt/sys-audio/README.md

@@ -92,7 +92,7 @@ will fail. To be able to use the device again:
 
 ### How to use USB devices
 
-Please refer to the [sys-usb formula instructions](../sys-usb/README.md).
+Please refer to the [usage of sys-usb](../sys-usb/README.md#usage).
 
 ### How to use Bluetooth
 

salt/sys-audio/install-client.sls

@@ -8,7 +8,8 @@ SPDX-License-Identifier: AGPL-3.0-or-later
 
 include:
   - utils.tools.common.update
-  ## qubes-usb-proxy: integrated camera and external USB.
+  ## TODO: video-companion covers camera, what about external USB speakers/mic?
+  ## qubes-usb-proxy: external USB microphone and speakers
   - sys-usb.install-client-proxy
 
 "{{ slsdotpath }}-client-installed":

salt/sys-usb/README.md

@@ -130,6 +130,16 @@ To use these devices, there are two options:
     - Disadvantages:
         - Some applications might not work due to not finding the device.
 
+3. Using [video-companion](../video-companion/README.md) to access webcam:
+    - Advantages:
+        - The most secure for client and server as the physical devices are
+          unmanaged;
+        - Least latency.
+    - Disadvantages:
+        - Can't use video-companion to screen share and share webcam at the
+          same time; and
+        - Does not cover audio.
+
 ## Credits
 
 - [Unman](https://github.com/unman/shaker/blob/main/sys-usb)