Intra-refreshing Control for Video Telephony Packet Loss
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Solution Overview
Problem
Conventional intra-refreshing methods in video telephony systems frequently transmit unnecessary I-frames, leading to a decrease in the average transmission rate of video frames due to the lack of consideration for the processing state of the video encoder and receiver, resulting in reduced frame rates and ineffective image quality recovery.
Innovation Solution
Implementing a method and apparatus that control the intra-refreshing operation by checking the sequence number and CRC of video data, allowing the transmitter and receiver to variably control the transmission time of I-frames based on detected errors and frame types, and estimating the number of P-frames between I-frames to optimize frame rate and transmission delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If intra-refreshing requests are frequently transmitted to recover image quality, then error recovery capability is improved, but average frame rate decreases due to unnecessary I-frame transmissions
Solution Approach 1:
The patent implements dynamic control of intra-refreshing operations by having the receiver check sequence numbers and frame types of transmitted video data, then selectively requesting I-frames based on actual error conditions and current encoder state. This replaces static frequent intra-refreshing with adaptive, condition-based requests that maintain error recovery capability while reducing unnecessary transmissions.
Solution Approach 2:
The patent establishes a feedback mechanism where the receiver monitors the transmitter's video data sequence numbers and frame types, then sends intra-refreshing requests only when actual errors are detected and the encoder is in an appropriate state. This feedback loop prevents blind frequent requests and coordinates refresh operations with the actual transmission state, improving frame rate while maintaining reliability.
2Reliability
If I-frames are transmitted in response to every intra-refreshing request, then image quality recovery is improved, but transmission delay increases due to encoder processing time
Solution Approach 1:
The patent checks the transmitter's current encoding state (sequence number and frame type) before requesting intra-refreshing, and the transmitter checks its own processing state before generating I-frames. This preliminary checking prevents requests during high-load periods and avoids unnecessary I-frame generation, reducing transmission delay while maintaining effective image quality recovery when truly needed.
3Productivity
If the transmitter processes video data without considering intra-refreshing state, then encoding efficiency is improved, but image quality recovery effectiveness decreases
Solution Approach 1:
The patent implements bidirectional feedback where the receiver monitors the transmitter's sequence numbers and frame types, and the transmitter monitors its own encoding state. This feedback enables both parties to coordinate intra-refreshing operations, ensuring I-frames are requested and generated only when the encoder is in an appropriate state, thereby maintaining encoding efficiency while improving recovery effectiveness.
Solution Approach 2:
The transmitter performs self-checks of its encoding state (current frame type and sequence number) before responding to intra-refreshing requests. This self-service mechanism allows the transmitter to autonomously determine whether to generate I-frames or continue normal encoding, maintaining encoding efficiency while ensuring effective image quality recovery when needed.
Data Source
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AI summary
A method and apparatus for controlling intra-refreshing in video telephone communication system are provided. A reception apparatus checks sequence number and CRC for received video packet data to detect presence of packet loss, decodes received video data to check frame type information, generates control signal for requesting intra-refreshing in accordance with checked frame type information and sequence number, and transmits generated control signal for requesting intra-refreshing to transmission apparatus. The transmission apparatus determines whether control signal for requesting transmission of I-frame obtained by compressing independent image is received from reception apparatus, checks frame type information and sequence number of video data being compressed, determines whether to transmit temporary I-frame corresponding to received control signal or to transmit I-frame based on predetermined period, in accordance with checked frame type information and sequence number, and transmits the I-frame to reception apparatus using variable time.