Video Multicast Optimization via Frame Segmentation
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Solution Overview
Problem
Current wireless data networks face challenges in efficiently distributing video streams due to limitations in multicast technology, which results in decreased data rates and increased transmission times, leading to issues like stuttering video and data loss, especially when client devices are far from the access point or in compromised signal conditions.
Innovation Solution
A network device determines whether to transmit frames unicast or multicast based on frame characteristics, such as key frames, and client device states, allowing for optimized video distribution by sending key frames at full data rates with error control and non-key frames at lower rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multicast transmission rate is decreased to increase reliability, then reliability of multicast transmissions is improved, but transmission time increases dramatically
Solution Approach 1:
The patent segments the video stream into key frames (I-frames) and non-key frames (P-frames and B-frames). Key frames are transmitted via unicast with high reliability to ensure critical video data reaches all clients, while non-key frames are transmitted via multicast with lower overhead. This segmentation allows the system to prioritize reliable delivery of essential data without sacrificing overall transmission efficiency.
Solution Approach 2:
The patent applies different transmission quality levels to different types of data packets. Key frames receive high-quality unicast transmission with error control and retransmission guarantees, while non-key frames receive lower-quality multicast transmission. This local differentiation of quality ensures that critical video reconstruction data is protected while maintaining efficient distribution for less critical update frames.
2Loss of time
If multicast transmission rate is increased to decrease transmission time, then transmission time is reduced, but data loss increases for distant or compromised client devices
Solution Approach 1:
The patent divides the video stream into critical key frames and less critical non-key frames. By transmitting key frames via unicast at full data rates with error control, the system ensures that even distant or compromised clients receive reliable video data. Non-key frames are transmitted via multicast at higher rates, accepting some data loss but maintaining overall video quality through the presence of key frames.
Solution Approach 2:
The patent transmits key frames beforehand with redundant error control mechanisms and retransmission protocols. This cushioning approach ensures that even if non-key frames are lost during high-rate multicast transmission, clients can reconstruct acceptable video quality using the reliably delivered key frames as reference points.
3Adaptability or versatility
If a single multicast stream is converted to multiple unicast streams to accommodate more client devices, then number of supported clients increases, but transmission time increases
Solution Approach 1:
The patent segments the stream distribution approach by type of frame. For key frames, it uses multiple unicast streams to reach individual clients reliably, ensuring each client receives critical video data. For non-key frames, it uses a single multicast stream to efficiently distribute update data to all clients simultaneously. This hybrid approach balances client coverage with transmission efficiency.
Solution Approach 2:
The patent merges multicast and unicast transmission methods into a unified video distribution system. By combining the efficiency of multicast for non-key frames with the reliability of unicast for key frames, the system achieves both broad client support and acceptable transmission times, overcoming the limitations of using either method alone.
Data Source
AI summary
A network device includes a communication interface and a processor. The communication interface may receive a multicast stream that includes a frame. The processor is coupled to the communication interface and may determine whether to send the frame unicast or multicast. The communication interface transmits the frame unicast or multicast based on the determination by the processor. The determination by the processor may be based on characteristics of the frame. If the characteristics of the frame include characteristics of a key frame such as an I-frame, the processor may determine to transmit the frame unicast. The determination may also be based on a predetermined state of client devices that are to receive the frame. If a client device is in a predetermined state such as a power save state, the processor may determine to transmit the frame unicast to that client device. Other embodiments are also described.