Video Communications

最新推荐文章于 2025-05-22 15:27:30 发布

原创最新推荐文章于 2025-05-22 15:27:30 发布 · 776 阅读

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Real-time video communication applications (consumer video chat, enterprise videoconferencing, etc.) are experiencing extremely rapid growth. Fueling that growth are ubiquitous, inexpensive personal computers, high speed broadband services and smartphones with unprecedented computing power. H.264 Scalable Video Coding technology addresses the most critical factors necessary for real-time video communication deployment. These are:

Low latency
Error resilience
Rate adaption
Scalable multi-endpoint support

Due to the crucial need for latency minimization in real-time video communications, error resilience methods such as packet retransmission used in HTTP are not viable. Unidirectional transport protocols such as UDP achieve the requirement for low latency but are subject to packet loss. SVC elegantly addresses the packet loss problem with very robust error resilience – 1) the SVC base layer is typically a small portion of the overall stream so it is statistically unlikely to lose packets, 2) base layer can also be strongly protected using FEC with far less overhead than applying FEC to the entire stream, 3) error concealment is significantly improved because predicting higher resolution layers using the base layer at the current time avoids glitches caused from using higher resolution layers from earlier in the stream.

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Improved Error Resilience Using SVC

SVC also supports real-time rate adaption, providing to each end-point the maximum quality stream possible based on its capabilities (resolution, frame rate, power) and current network conditions.

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SVC enables each endpoint to have optimal video quality while minimizing bandwidth usage

In the case of multi-endpoint applications, SVC eliminates the costs associated with today’s solutions using Multipoint Conferencing Units (MCUs). By reducing the cost of high quality, multi-endpoint chats so dramatically, SVC is clearly a key enabling technology for deploying real-time video communication on a massive scale. Video quality is also significantly enhanced by eliminating generational loss and processing latency incurred inside the MCU.

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