5.3 KiB
Please read Build and install page before going further.
Quick rundown
The first step to create a virtual camera is defining a virtual device:
AkVCamManager add-device "Virtual Camera"
The command will return a message like:
Device created as AkVCamVideoDevice0
Keep track of AkVCamVideoDevice0, that will be the identifier of the virtual device and you will need it for the following operations. The created device is a blank device without any defined capture formats, that meaning it won't work as-is.
Now, you must define a at least one capture format for that device, as:
AkVCamManager add-format AkVCamVideoDevice0 FORMAT WIDTH HEIGHT FRAME_RATE
For example:
AkVCamManager add-format AkVCamVideoDevice0 YUY2 640 480 30
First format defined is the default frame format.
You can list all capture formats with:
AkVCamManager supported-formats --output
The frame rate can be expressed either as an integer or a fraction, for example 15/2.
Once you finished defining your devices, you must obligatorily apply the changes to the system with.
AkVCamManager update
Note: You must run an update every time you modify any parameter of the virtual camera. Also NEVER modify the virtual camera parameters when a client is running it.
Managing the devices
List all devices:
AkVCamManager devices
You can remove a device with:
AkVCamManager remove-device AkVCamVideoDevice0
Or you can remove all devices:
AkVCamManager remove-devices
You can change the device description with:
AkVCamManager set-description AkVCamVideoDevice0 "My Virtual Camera"
Or get the device description with:
AkVCamManager description AkVCamVideoDevice0
Managing the formats
List all formats:
AkVCamManager formats AkVCamVideoDevice0
Add a new format at a given index:
AkVCamManager add-format --index 5 AkVCamVideoDevice0 YUY2 640 480 30
Remove a device format at INDEX with:
AkVCamManager remove-format AkVCamVideoDevice0 INDEX
Remove all device formats:
AkVCamManager remove-formats AkVCamVideoDevice0
You can get the default recommended output format with:
AkVCamManager default-format --output
No signal picture
When a client program try to play the virtual camera but it isn't receiving any frame, it will show a random dot pattern, you can change it to show a custom picture instead with:
AkVCamManager set-picture /path/to/place_holder_picture.png
And you can get place holder picture path again with:
AkVCamManager picture
You must give a full path to a picture file, the supported formats for the picture are:
- BMP (24 bpp and 32 bpp).
- JPG
- PNG
Loading configurations from a file
Alternatively, you can define and configure all virtual devices at once using an INI file like.
The INI file follows QSettings file format.
Once you have finished writing your settings file, you can pass it to the manager as:
AkVCamManager load settings.ini
You don't need to call update because load will automatically call it for you.
Before continue, let make it clear that the order of the sections (those enclosed between [ ]) or it's fields (those lines in the form of key = value) does not matters, we are just putting it in natural order to make it easier to understand.
Defining the devices
Following is the code for defining the devices:
[Cameras]
cameras/size = 2
cameras/1/description = My Virtual Camera
cameras/1/formats = 1
cameras/2/description = My Other Virtual Camera
cameras/2/formats = 1, 2
First at all you must create a [Cameras] section and set the number of webcams that will be defined with cameras/size, cameras indexes starts with 1. Each camera has the following properties:
- description: The description that will shown to the capture or streaming program.
- formats: is a comma separated list of index of formats supported by the device, we will talk about this in a moment.
Defining the formats
Next step is defining the formats:
[Formats]
formats/size = 2
formats/1/format = YUY2
formats/1/width = 640
formats/1/height = 480
formats/1/fps = 30
formats/2/format = RGB24, YUY2
formats/2/width = 640
formats/2/height = 480
formats/2/fps = 20/1, 15/2
format can be set to any pixel format we been talk before, then set the frame resolution with width and height, fps sets the frame rate and it can be either a positive integer number or a positive fraction in the form numerator/denominator.
You may be noted that the second format has comma separated values, this is because you can actually define many formats with similar properties at once with just a minimal number of lines. The driver will combine the values, so for format 2 in this example you get the following formats:
- RGB24 640x480 20 FPS
- RGB24 640x480 7.5 FPS
- YUY2 640x480 20 FPS
- YUY2 640x480 7.5 FPS
If you want a good compatibility with many capture programs you must provide at least the YUY2 640x480 format in your devices.
No signal picture
You must add the following lines to the settings file for setting the place holder picture:
[General]
default_frame = /path/to/place_holder_picture.png