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What is Affecting Video Latency

A project log for The VLT - Video Latency Tester

The VLT is a tool to measure how long it takes (in milliseconds) for a video signal to change from one state to another.

nathan-danielsNathan Daniels 10/02/2017 at 09:260 Comments

Another test was to deliberately ‘stress test’ the CPU and then gather the timing results. To achieve this I issued the following command in the macOS terminal of a MacBook Air:

yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null &

This created four processes that consumed a significant amount of CPU percentage in the Activity Monitor utility of macOS. In this test the results were as expected, and the timing was delayed; even if it was by only a small average amount of 64.5 milliseconds. The table below shows how the timing is delayed a little when the CPU is busy processing.

To turn off the ‘stress test’ issue the following command:

killall yes

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