Distributed Multiplexing for Video Streams
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Solution Overview
Problem
Existing communication systems face inefficiencies in handling variable bit-rate (VBR) video streams, as they require complex statistical multiplexers to manage varying data amounts, leading to increased complexity and resource usage, especially when combining multiple streams into a single channel.
Innovation Solution
The method synchronizes the sizes and data transmission timing of multiple VBR video streams to create a single multi-program transport stream that is substantially smaller than the aggregate size of the separate streams, without time-shifting or recompressing the data, using rate adapters to allocate bandwidth and process streams for synchronized transmission in separate channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If statistical multiplexers are used to combine multiple VBR video streams onto a single channel, then the combined stream size is reduced by exploiting statistical multiplexing gains, but the device complexity and processing workload increase significantly
Solution Approach 1:
The system divides the multiplexing function into two independent parts: (1) a rate adapter that converts each VBR stream into a synchronized VBR stream with controlled peak rates, and (2) a simple combiner that merges the synchronized streams. This segmentation eliminates the need for a complex statistical multiplexer while preserving multiplexing gains.
Solution Approach 2:
The rate adapter performs preliminary processing on each VBR stream before combining, by determining peak bit rates and inserting synchronization markers. This preliminary action prepares the streams for simple addition at the combiner, avoiding the need for complex real-time statistical multiplexing.
2Adaptability or versatility
If VBR streams are encapsulated in CBR channels with padding bits to handle variable data amounts, then the streams can be transmitted through standard protocols, but the transmission efficiency decreases due to wasted bandwidth
Solution Approach 1:
The system transitions from static CBR encapsulation to dynamic VBR transmission by synchronizing multiple VBR streams so their peak rates occur at different times. This dynamic approach allows the combined stream to maintain variable bit rate while achieving statistical multiplexing gains, improving bandwidth efficiency without sacrificing protocol compatibility.
3Ease of operation
If QAM modulators combine multiple CBR streams into a multi-program CBR stream, then the combining process is simple, but the peak bit rate of the combined stream equals the sum of individual peak rates, losing statistical multiplexing benefits
Solution Approach 1:
The system merges synchronized VBR streams at the QAM modulator, but the streams are first processed by rate adapters that ensure their peak rates are staggered in time. This allows the simple combining operation to achieve statistical multiplexing gains, reducing the combined stream size below the sum of individual peak rates.
Data Source
AI summary
The present invention is directed to a method of delivering a video stream. The method operates by determining a group of video streams to be provided to a particular destination over a particular communication link. Next, the band width of the link is allocated to the video streams based upon the particular properties of the various video streams to be transmitted. The video streams are processed so that they fit into the band width allocations. Next, the video streams are transmitted in separate channels, synchronized with respect to each other, to reach the subject destination.