Video Encoder Error Propagation Recovery via Feedback
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Solution Overview
Problem
Existing video transmission systems experience severe distortions due to error propagation when frames are lost during transmission, leading to bitrate overshoots and increased source coding distortion, which can cause further losses and perceptual disturbances.
Innovation Solution
The system generates partial recovery frames over a period of time, using techniques like intra refresh to progressively refresh macroblocks based on an error propagation distortion map, triggered by feedback from the decoder, to minimize error propagation and maintain a smooth bitrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a recovery frame is sent to stop error propagation, then error propagation is terminated, but bitrate overshoots and source coding distortion increase
Solution Approach 1:
The patent divides the frame into multiple regions and processes error recovery in segments rather than forcing a complete frame refresh. By identifying and refreshing only the affected regions where error propagation occurs, the system terminates error propagation effectively while avoiding the bitrate overshoot associated with encoding entire frames using intra prediction.
Solution Approach 2:
The patent applies different encoding strategies to different regions of the frame based on error propagation analysis. Regions affected by error propagation are refreshed using intra prediction or reference from error-free frames, while regions without error propagation continue using efficient inter prediction. This localized approach maintains reliability where needed while preserving bitrate efficiency elsewhere.
2Reliability
If a recovery frame is sent to stop error propagation, then error propagation is terminated, but source coding distortion increases
Solution Approach 1:
The patent segments the frame processing to apply recovery operations only where error propagation is detected. By analyzing error propagation patterns and limiting recovery operations to affected regions rather than the entire frame, the system terminates error propagation effectively while minimizing the introduction of new coding distortion in unaffected regions.
Solution Approach 2:
The patent applies recovery operations selectively to specific regions based on error propagation analysis. Affected regions receive intra prediction or error-free references to terminate propagation, while unaffected regions maintain their original prediction mode. This localized recovery approach ensures error termination where needed while preserving image quality and minimizing overall coding distortion.
3Loss of energy
If inter frame encoding is used to compress video, then bitrate efficiency is improved, but error propagation occurs when frames are lost
Solution Approach 1:
The patent implements a feedback mechanism where the encoder receives information from the decoder about lost or corrupted frames. Based on this feedback, the encoder dynamically adjusts its encoding strategy, switching to intra prediction or error-resilient modes for affected regions in subsequent frames. This feedback-driven approach maintains inter prediction efficiency for good frames while automatically activating error protection where needed.
Solution Approach 2:
The patent makes the encoding mode dynamic rather than static. The encoder continuously adapts its prediction strategy based on channel conditions and error propagation patterns. When error propagation is detected in certain regions, the system dynamically switches those regions to more robust encoding modes (intra prediction or error-free references) while maintaining efficient inter prediction in stable regions, optimizing both bitrate efficiency and reliability in real-time.
Data Source
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AI summary
A method comprising: encoding a video image at each of a plurality of frames, including by using inter frame encoding to encode at least portions of some of the frames, thereby generating an encoded video stream; transmitting the encoded video stream over a lossy channel to be decoded at a receiver to produce decoded video; and performing a recovery operation to refresh the encoding of the video image, cutting off error propagation that has occurred in the decoded video due to an effect of inter prediction in presence of loss over said channel; wherein said recovery operation is triggered by a report fed back from the receiver indicative of loss; and wherein the recovery operation is performed over a plural number of frames, refreshing the encoding of different partial frame regions at different respective frames.