Multi-Layer Video Encoding CRF Control Without Rescan Overhead
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multi-layer video coding schemes face difficulties in widespread adoption due to the lack of efficient CRF-based rate control mechanisms, leading to inflexible and inefficient encoding processes that do not effectively utilize the complex non-linear relationships between encoding parameters across different layers.
Innovation Solution
A CRF-based rate control method for multi-layer video encoding that converts a single encoding quality factor into specific factors for both base and enhancement layers, allowing for flexible and efficient encoding by adapting to the properties of the base encoding, thereby mimicking existing single-layer encoding approaches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-layer video coding schemes are implemented, then encoding flexibility and efficiency are improved, but device complexity and difficulty of implementation increase
Solution Approach 1:
The patent introduces an intermediary CRF calculator that acts as a mediator between the single CRF parameter input and the multiple encoding parameters required by multi-layer coding schemes. This calculator converts the simple CRF input into appropriate quantization parameters and bit rate allocations for base and enhancement layers, shielding users from the complexity of multi-layer encoding while enabling flexible adaptation to different coding schemes like LCEVC, SVC, and SHVC.
Solution Approach 2:
The patent replicates the successful single-layer CRF encoding interface and control mechanism for use in multi-layer contexts. By copying the familiar CRF parameter approach from single-layer encoding and adapting it through the CRF calculator, the system maintains the ease of use and predictability of single-layer encoding while enabling the benefits of multi-layer coding schemes.
2Manufacturing precision
If CRF-based rate control is applied to multi-layer encoding, then visual quality is improved, but computational overhead and encoding time increase
Solution Approach 1:
The patent performs preliminary calculations in the CRF calculator to determine appropriate quantization parameters and bit rate allocations for both base and enhancement layers before the actual encoding process. By pre-computing these parameters based on the input CRF value and video characteristics, the system avoids the need for time-consuming rescan operations and iterative adjustments during encoding, thus maintaining high visual quality while reducing encoding time.
Solution Approach 2:
The patent implements feedback mechanisms where the CRF calculator monitors encoding progress and adjusts parameters dynamically. The system uses feedback from base layer encoding results to optimize enhancement layer parameters, ensuring high visual quality is achieved without requiring multiple full rescans of the video content, thereby reducing overall encoding time.
3Ease of operation
If constant bit rate encoding is used, then bit rate control is simplified, but visual quality consistency across different scene complexities deteriorates
Solution Approach 1:
The patent applies local quality principles by allowing different quantization parameters and bit rate allocations for base and enhancement layers based on local scene characteristics. The CRF calculator analyzes video complexity and dynamically adjusts parameters for each layer and scene region, ensuring that complex scenes receive more bits while simple scenes use fewer bits, thereby maintaining consistent visual quality across varying scene complexities while keeping bit rate control straightforward through the single CRF parameter.
Data Source
AI summary
A method of computing encoding parameters for an encoding of an input video is described. The method may be seen as a form of constant rate factor control for a multi-layer coding scheme. The method includes receiving an encoding quality factor indicating a desired visual quality for an encoding of the input video. The encoding quality factor is mapped to a base quality factor indicating a desired visual quality for a base encoding of the input video, the base encoding providing an encoding at a first level of quality. Base encoding parameters are obtained from a base encoder. The encoding quality factor, base quality factor, and base encoding parameters are mapped to enhancement encoding parameters for an enhancement encoding, wherein a combination of the base encoding and the enhancement encoding provide an encoding at a second level of quality that is higher than the first level of quality. Also, two modes for constant rate factor control are described. In a “charging” mode, an encoding quality factor is selectively modulated based on characteristics of the input video. In an “accurate” mode, an encoding quality factor is selectively recomputed based on encoding parameters.