9.7. Webcam passthrough

9.7.1. Using a host webcam in the guest

VirtualBox 4.3 includes an experimental feature which allows a guest to use a host webcam. This complements the general USB passthrough support which was the typical way of using host webcams in earlier versions. The webcam passthrough support can handle non-USB video sources in theory, but this is completely untested.

Note

The webcam passthrough module is shipped as part of the Oracle VM VirtualBox extension pack, which must be installed separately. See Section 1.5, “Installing VirtualBox and extension packs” for more information.

The host webcam can be attached to the VM using "Devices" menu in the VM menu bar. The "Webcams" menu contains a list of available video input devices on the host. Clicking on a webcam name attaches or detaches the corresponding host device.

The VBoxManage command line tool can be used to enable webcam passthrough. Please see the host-specific sections below for additional details. The following commands are available:

Get a list of host webcams (or other video input devices):
```
VBoxManage list webcams
```
The output format:
```
alias "user friendly name"
host path or identifier
```
The alias can be used as a shortcut in other commands. Alias '.0' means default video input device on the host, '.1', '.2', etc mean first, second, etc video input device. The device order is host-specific.
Attach a webcam to a running VM:
```
VBoxManage controlvm "VM name" webcam attach [host_path|alias [settings]]
```
This will attach a USB webcam device to the guest.

The settings parameter is a string Setting1=Value1;Setting2=Value2, which allows to configure the emulated webcam device. The following settings are supported:
- MaxFramerate The highest rate at which video frames are sent to the guest. A higher frame rate requires more CPU power. Therefore sometimes it is useful to set a lower limit. Default is no limit and allow the guest to use all frame rates supported by the host webcam.
- MaxPayloadTransferSize How many bytes the emulated webcam can send to the guest at a time. Default value is 3060 bytes, which is used by some webcams. Higher values can slightly reduce CPU load, if the guest is able to use larger buffers. However, a high MaxPayloadTransferSize might be not supported by some guests.

Detach a webcam from a running VM:

VBoxManage controlvm "VM name" webcam detach [host_path|alias]

List webcams attached to a running VM:
```
VBoxManage controlvm "VM name" webcam list
```
The output contains path or alias which was used in 'webcam attach' command for each attached webcam.

9.7.2. Windows hosts

When the webcam device is detached from the host, the emulated webcam device is automatically detached from the guest.

9.7.3. Mac OS X hosts

OS X version 10.9 or newer is required.

When the webcam device is detached from the host, the emulated webcam device remains attached to the guest and must be manually detached using the VBoxManage controlvm "VM name" webcam detach ... command.

9.7.4. Linux and Solaris hosts

When the webcam is detached from the host the emulated webcam device is automatically detached from the guest only if the webcam is streaming video. If the emulated webcam is inactive it should be manually detached using the VBoxManage controlvm "VM name" webcam detach ... command.

Aliases .0 and .1 are mapped to /dev/video0, alias .2 is mapped to /dev/video1 and so forth.