Video Camera Latency Analysis and Measurement

All modern video cameras exhibit some latency between the scene being captured and the output video signal. This camera latency is significant to the overall latency of a video network transmission chain. Some real-time applications based on video sharing require very low latency and selecting the right camera is then crucial. We observed how video cameras operate regarding their latency. We proposed three methods to measure camera latency: timecode view, waveform shift, and screen photodetector methods. All methods can achieve a subframe resolution and precision of approximately 1 ms although with varying levels of automation, convenience and suitability for particular cameras. We discuss arrangements that affect measurement precision. We applied the proposed methods to a sample camera, and we show measurements results for several other cameras. The measurement results showed that the fastest cameras provide latencies lower than 5 ms, which should be fast enough even for demanding real-time applications. However, most cameras still exhibit latencies at the range of 1-3 video frames.