HEVC Temporal Hierarchy Bit Rate Control
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Solution Overview
Problem
Existing methods for controlling frame rates in HEVC-encoded moving images based on temporal scalability struggle to maintain desired bit rates and frame rates, particularly when thinning out frames with lower priorities, leading to incomplete reproduction of frame groups at 30 FPS and 60 FPS.
Innovation Solution
An image processing apparatus that acquires temporal hierarchy information for encoding target frames and determines encoding parameters based on past frames' bit rates, allowing for adaptive bit rate and frame rate control according to effective transmission rates and temporal IDs, ensuring that bit rates are managed within the communication path's capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If frames with lower priorities are thinned out to control transmission bit rate, then transmission bit rate is reduced, but frame groups at 30 FPS and 60 FPS cannot be completely reproduced
Solution Approach 1:
The patent dynamically adjusts the thinning ratio based on temporal ID hierarchy, where different temporal levels (temporal ID 0, 1, 2, 3) have different thinning ratios applied. This dynamic adaptation allows the system to maintain frame group completeness for higher frame rates while controlling overall bit rate, resolving the contradiction between bit rate reduction and reproduction completeness.
Solution Approach 2:
The patent segments frames into different temporal hierarchies (temporal ID levels) and applies different thinning strategies to each segment. Lower temporal ID frames (higher priority) are preserved with lower thinning ratios, while higher temporal ID frames (lower priority) are thinned more aggressively. This segmentation allows selective preservation of critical frames needed for 30 FPS and 60 FPS reproduction while reducing overall bit rate.
2Reliability
If all frames are transmitted to maintain frame group completeness, then frame reproduction is complete, but transmission bit rate exceeds communication path capacity
Solution Approach 1:
The patent changes the parameter of thinning ratio based on temporal ID, where each temporal hierarchy level has a predetermined thinning ratio. This parameter change allows the system to transmit fewer high-temporal-ID frames while maintaining completeness of lower-temporal-ID frames, thus controlling bit rate within communication path capacity while ensuring frame group reproduction.
Solution Approach 2:
The patent applies different quality levels (thinning ratios) to different temporal hierarchy segments. Critical frames with lower temporal IDs maintain higher quality (lower thinning), while less critical frames with higher temporal IDs accept lower quality (higher thinning). This local quality differentiation ensures frame group completeness for essential frame rates while controlling overall transmission bit rate.
3Productivity
If frames are thinned out based on priority to control bit rate, then transmission efficiency is improved, but average bit rate may still exceed transmission rate
Solution Approach 1:
The patent uses feedback from communication path status and reception buffer state to dynamically adjust encoding parameters and thinning ratios. The encoding apparatus receives feedback about transmission conditions and buffer states, then adapts the thinning ratios and encoding settings to ensure average bit rate matches transmission rate, maintaining transmission efficiency while preventing bit rate overload.
Data Source
AI summary
An image processing apparatus according to the present invention is configured to encode frames forming a moving image using temporal hierarchies, and includes an acquisition unit configured to acquire information related to a temporal hierarchy corresponding to an encoding target frame, a determination unit configured to determine, based on the information related to the temporal hierarchy acquired by the acquisition unit, whether to use an encoding parameter based on a bit rate of at least one past frame encoded before the encoding target frame is encoded, and an encoding unit configured to encode the encoding target frame using the encoding parameter based on the bit rate of the at least one past frame.