Video Switcher

Basic usage

UltraGrid

If you have multiple video sources you want to switch between during transmission, you can use video switcher dummy video driver, syntax is following:

uv --control-port 5054 -t switcher -t decklink:0 -t decklink:1

Note: the order of -t arguments is important, first must be "switcher", consequent capture parameters give the switcher possible inputs that can be switched to. It is usually a good point to have the same video format from all sources, although not required.

Control

Switching registers interactive control via keyboard control, it means that it is sufficient to press 1, 2 .. n for first to n-th input in terminal in which UltraGrid is run.

Alternatively, it can be controlled via a control socket, eg:

echo 'capture.data 0' | busybox nc localhost <control_port>

Note: There is a difference between indices over control port and keyboard. First is 0-indexed, keyboard control uses 1-indexed keys, so first input has key "1" but index "0". The shift for keyboard control is to have the inputs on the keyboard physically next each other.

Note 2: netcat from busybox is used because it has defined behavior (other implementation may also need '-N' to close connection after processing the command).

Capture filters

You may also apply capture filters for individual inputs:

uv --control-port  -t switcher --capture-filter blank 0:0:100:100 -t testcard --capture-filter 1000:0:80:100 decklink

Here --capture-filter parameter relates directly to nearest succeeding -t parameter.