Krishna Prabhakaran, eInfochips
embedded.com (June 16, 2014)
Lag-time in video games and video conferencing is annoying. Lag-time in avionics, medical devices, and industrial video systems is mission-critical. That’s why low latency video systems are proliferating in applications where live video feeds need to be processed and analyzed in real time. This article discusses some of the various contributors to latency in video systems, and ways of minimizing their impact at the video source and playback ends.
The need for speed
For consumers and business users, lag time is commonly experienced in video games and video conferencing. Lag time in video games leads to being overrun by enemies, eliminated by other players, or in the case of massive Star Craft games, it leads to a stadium full of angry fans. In real-time business systems, low-latency video conferencing is also important. Without it, mismatched voice and video cause confusion and frustration. High latency in a video conferencing system can disrupt a conversation to the extent that it defeats the purpose of using video conferencing to increase productivity. In mission critical applications, the severity of high latency consequences is multiplied, such as in Unmanned Aerial Vehicles (UAVs), video assisted surgery, and mid-air refueling.
UAVs used in tactical strikes on enemy targets and video-assisted surgeries such as endoscopy and laparoscopy appear to be unrelated, yet both rely on accurate information - an accuracy that can only be provided by low latency video systems. If the latency is too great, the consequences can be catastrophic, such hitting the wrong target with the UAV's payload or missing a crucial element during surgery.
During mid-air refueling, military pilots are trying to orient the aircraft’s fuel inlet to the fuel pipe of a fuel carrier aircraft. Again, video systems play a critical role here, capturing and sending live video feeds of the inlet to the pilot in real time. In this instance, the success of the entire operation is highly dependent upon the latency between the captured video at its source and the video displayed on the screen in the cockpit.
When making mission-critical decisions based on video feeds, low latency is essential. In my examples, higher latency could lead to the UAV targeting an unintended area, doctors making misplaced incisions, and military aircraft running out of fuel. This could ultimately lead to serious property damage, failed missions, and loss of life.
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