![]() ![]() Once a signal is received at the input port of an encoder, there are a number of DSP operations that take place: 1) scaling the signal for transmission, 2) frame rate conversion (if needed), 3) chroma sub-sampling (if needed), 4) compressing the signal (if needed), and more. It’s important to understand the basic steps involved in transmitting video over a network in order to interpret manufacturers’ latency claims and apply that to lip sync capabilities. However, it’s never “zero.” If a product is touted as having zero latency, the data is likely erroneous (or the marketing department is in full spin mode). If there is noticeable delay in signal delivery, the un-synced video can be very distracting, while the unaligned audio can result in phase cancellations.Īll systems have latency, but it may be of such small value that it has no noticeable impact on the user experience. In that scenario, it’s important for transmissions to reach each endpoint simultaneously, or as closely as possible. System latency is additive, so each step in the processing chain adds a portion to the overall transmission latency.Īnother common case to consider is when the same audio or video signal is transmitted to multiple endpoints (speakers and displays) within the same space or room. This processing can take the form of an equalizer for an audio signal, resolution scaling of a video signal, or even the amount of time it takes for a monitor to display an image (i.e. For signal processing, it’s the amount of time from the point it enters the processing circuit until it emerges as the output. In the context of networks, latency is the time it takes for a signal to travel over the connection (be it copper or fiber) from the source endpoint/node to its destination endpoint/node. Thus, it’s important to manage customers’ expectations with regard to the latency they should expect from their media distribution system.īefore we focus on the camera’s role in the latency chain, let’s revisit some of the other factors involved in media transmission. Not only is the window of acceptable latency for lip sync razor thin in this scenario, it’s compounded by the fact that the audio and video are often being processed by separate systems. Managing lip sync is particularly challenging in live environments, since the viewer can simultaneously watch the event itself and a reproduction of the event on a monitor or screen. Lip sync is the matching of lip movements to live or recorded video, and a critical element of good user experience. ![]()
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