FEC Packet Scheduling for Variable-Bit-Rate Stream Recovery
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Solution Overview
Problem
Current FEC schemes, such as the Pro-MPEG scheme, are ineffective for variable bit rate (VBR) streams as they fail to maintain a consistent FEC packet transmission rate and delay, leading to inefficiencies and delays in data recovery.
Innovation Solution
An FEC transmission processing apparatus and method that generates and transmits FEC packets within a predetermined FEC period after acquiring the first media packet of each coding block, ensuring consistent coding periods and minimizing delays, even in variable rate streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If FEC packets are transmitted according to the Pro-MPEG scheme with fixed matrix ranges, then coding can be realized during transmission without retention of data packets, but the transmission rate of FEC packets cannot be smoothly controlled and may increase more than expected in variable bit rate streams
Solution Approach 1:
The patent applies dynamics by making the FEC packet transmission range variable rather than fixed. The transmission range is dynamically adjusted based on the actual bit rate of the variable bit rate stream, allowing the system to adapt to changing transmission conditions. This resolves the contradiction by enabling smooth rate control while maintaining reliable FEC processing through adaptive range selection.
2Loss of time
If FEC packets are transmitted immediately with very short delay, then recovery can be performed quickly, but in variable bit rate streams this causes delays and bandwidth wastage due to inconsistent transmission rates
Solution Approach 1:
The patent implements periodic action by transmitting FEC packets at regular intervals within dynamically determined ranges. Instead of immediate transmission that causes rate inconsistency, FEC packets are transmitted periodically with controlled timing. This approach maintains acceptable recovery delay while ensuring consistent bandwidth usage in variable bit rate streams, resolving the contradiction between speed and efficiency.
3Reliability
If the transmission rate of FEC packets is increased to handle variable bit rate streams, then more data can be protected, but bandwidth reservations are exceeded and delays occur
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the FEC packet transmission range based on the actual bit rate. When the bit rate increases, the transmission range is expanded to provide broader data protection. When the bit rate decreases, the range is contracted to stay within bandwidth reservations. This adaptive parameter adjustment resolves the contradiction by providing adequate protection only when bandwidth is available, avoiding unnecessary delays.
Data Source
AI summary
There is provided with an FEC transmission processing apparatus including: a media packet acquiring unit configured to successively acquire media packets from a media packet generator; a media packet transmission unit configured to transmit the media packets acquired to a media packet reception processing apparatus; an FEC packet generation unit configured to generate a plurality of FEC packets for the media packet reception processing apparatus to recover a lost media packet by carrying out FEC calculation processing using media packets acquired within a predetermined FEC period from acquisition of a first acquired media packet after media packets subjected to the FEC calculation processing immediately before; and an FEC packet transmission unit configured to transmit the FEC packets to the media packet reception processing apparatus within the predetermined FEC period after a lapse of the predetermined FEC period from the acquisition of the first acquired media packet.