Periodic Intra Refresh Pattern for Video Encoding Bitrate Control
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Solution Overview
Problem
Video encoding methods, such as H.264, experience bitrate spikes due to I-frames containing more information than P- and/or B-frames, particularly in network monitoring cameras, which is undesirable for maintaining a constant network bitrate.
Innovation Solution
The method introduces delta frames between consecutive intra refresh frames in a periodic intra refresh pattern, allowing dynamic adjustment of the number of frames in an intra refresh cycle based on motion levels and bitrate allocation, thereby smoothing out bitrate spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If I-frames are used to encode complete image frames, then encoding accuracy and detail are improved, but bitrate spikes occur
Solution Approach 1:
The patent segments the image frame into multiple macroblock regions, where only a subset of macroblocks is encoded as I-frames while the rest are encoded as P-frames. This segmentation approach maintains encoding accuracy for critical regions while reducing overall bitrate by utilizing inter-frame prediction for non-critical regions.
Solution Approach 2:
The patent applies different encoding qualities to different regions of the image frame. Critical regions are encoded with higher quality using intra-frame coding, while non-critical regions use lower quality inter-frame coding. This local quality differentiation resolves the contradiction between overall encoding accuracy and bitrate reduction.
2Stability of the object's composition
If periodic intra refresh is applied to smooth bitrate, then bitrate stability is improved, but flexibility in adjusting number of frames is reduced
Solution Approach 1:
The patent introduces dynamic adjustment capability to the periodic intra refresh pattern. The number of frames between intra refresh cycles can be dynamically adjusted based on network conditions and motion levels, allowing the system to adapt to varying requirements while maintaining bitrate stability through the periodic refresh mechanism.
Solution Approach 2:
The patent enables changing the parameter of frame count between intra refresh cycles. By allowing the number of frames to be adjusted as a variable parameter, the system can adapt to different network conditions and motion levels while maintaining the core functionality of periodic intra refresh for bitrate smoothing.
3Ease of manufacture
If fixed intra refresh pattern is used, then implementation simplicity is maintained, but adaptability to motion levels is reduced
Solution Approach 1:
The patent incorporates feedback mechanisms that monitor network conditions and motion levels to dynamically adjust the intra refresh pattern. This feedback approach maintains implementation simplicity by using standard encoding frameworks while enabling adaptability through automated parameter adjustment based on real-time conditions.
Data Source
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AI summary
A video encoding method for encoding a series of images of original video data into an encoded video stream is disclosed. The video encoding method comprises setting a periodic intra refresh pattern for the encoding of the series of images of original video data; setting a number of delta frames (16) to be added between consecutive intra refresh frames (10) of the periodic intra refresh pattern, thereby adjusting the intra refresh periodicity of the encoded video stream; and encoding the series of images of original video data into the encoded video stream using the set periodic intra refresh pattern and the set number of delta frames (16) to be added between consecutive intra refresh frames (10). During the encoding, a current intra refresh frame (10) is set to directly refer to a previous intra refresh frame (10). During the encoding, each delta frame (16) added in between two consecutive intra refresh frames (10) is set to only refer to a previous one of the two consecutive intra refresh frames (10).