Video Coding Bit-Rate Segmentation for Constant Quality
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Solution Overview
Problem
Current video coding technologies face inefficiencies in achieving constant perceptual quality, leading to wasted bits in encoding variable content, as they typically use constant bit-rate encoding, which results in sub-optimal quality and larger file sizes.
Innovation Solution
A method involving the analysis of video sequences encoded at initial constant bit-rates, partitioning these into sub-ranges with different bit-rates to meet perceptual quality requirements, and iteratively adjusting these bit-rates to minimize the disparity in bit-counts, allowing for the creation of a near-constant quality video stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant bit-rate encoding is used, then the bit-rate is fixed and simple to implement, but the perceptual quality varies and file size is larger than necessary
Solution Approach 1:
The video sequence is divided into multiple segments or chunks, each of which is encoded at a different constant bit-rate. By segmenting the video content and applying different encoding parameters to different segments, the system achieves near-constant perceptual quality while reducing overall file size compared to uniform constant bit-rate encoding.
Solution Approach 2:
Different portions of the video sequence are encoded with different quality levels appropriate to their content characteristics. This local quality approach ensures that each segment meets the perceptual quality requirement for its specific content type, avoiding over-encoding of simple scenes and under-encoding of complex scenes, thereby optimizing the overall file size.
2Ease of manufacture
If constant bit-rate encoding is used, then the encoding process is simple, but the quality is sub-optimal for certain video genres
Solution Approach 1:
The encoding system dynamically adjusts the bit-rate for different segments of the video sequence based on content analysis. Rather than using a static constant bit-rate, the system adapts the encoding parameters to match the requirements of different video genres and content types, improving perceptual quality while maintaining a relatively simple encoding process.
Solution Approach 2:
The system changes the bit-rate parameter across different segments of the video sequence. By varying this key encoding parameter based on content characteristics, the system achieves genre-appropriate quality levels without requiring completely complex encoding algorithms, thus balancing simplicity with effectiveness.
3Quantity of substance
If variable bit-rate encoding is used to achieve constant perceptual quality, then file size is reduced, but the encoding complexity increases
Solution Approach 1:
The video sequence is divided into multiple segments or chunks, each of which is encoded at a different constant bit-rate. By segmenting the video content and applying different encoding parameters to different segments, the system achieves near-constant perceptual quality while reducing overall file size compared to uniform constant bit-rate encoding.
Solution Approach 2:
The video sequence is first encoded at one or more initial constant bit-rates before the iterative optimization process. This preliminary encoding creates a baseline that can be analyzed and improved upon through subsequent iterative adjustments, reducing the complexity of achieving optimal variable bit-rate encoding from scratch.
Data Source
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AI summary
Methods and apparatus for video coding are disclosed, particularly for use in relation to video compression. Many commercially available video encoders support constant bit-rate encoding but not constant quality encoding. Aspects of the present invention are concerned with methods and apparatus for video coding, the methods involving the determination of bit-rates at which a constant bit-rate encoder may be operated such that segments of video can be chosen from files encoded at the bit-rates so-determined in order to produce an output bitstream in which the quality is nearly constant. Bitstream segments may be chosen from a low bit-rate bitstream for easy-to-compress scenes, and from a high bit-rate bitstream for hard-to-compress scenes.