Film Grain SEI Insertion for Bit-Accurate Video Simulation
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Solution Overview
Problem
The H.264 standard does not specify a procedure for simulating film grain in video systems, leading to non-compliance with bit-accurate film grain simulation during trick mode play, as existing solutions like the second prior art approach are not compliant with the standard's display order requirements.
Innovation Solution
A method for simulating film grain by providing film grain supplemental information corresponding to intra and inter coded pictures in decode order, ensuring that only one SEI message precedes each I, P, and B picture, with the SEI message for B pictures being the same as that of the preceding I or P picture, aligning with the H.264 standard's display order.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If film grain SEI messages are transmitted only preceding I frames in decoding order, then bit-accurate film grain simulation is achieved, but compliance with H.264 standard display order requirement is lost
Solution Approach 1:
The film grain simulation process is segmented into two independent ordering systems: decoding order for bit-accuracy and display order for standard compliance. SEI messages are inserted at specific points in the bitstream corresponding to I pictures in decoding order, while the simulation application follows display order, creating distinct segments for each requirement
Solution Approach 2:
A mapping mechanism acts as an intermediary between decoding order and display order. The system uses picture order count (POC) values and frame numbering to translate SEI message positions from decoding order to display order, allowing the decoder to apply grain parameters correctly regardless of playback mode
2Stability of the object's composition
If film grain SEI messages are transmitted for every inter coded picture, then consistent film grain simulation is achieved, but bit-stream overhead increases
Solution Approach 1:
Film grain SEI messages are transmitted periodically at I picture boundaries rather than continuously for every frame. This periodic insertion at regular intervals (I pictures) maintains consistent grain simulation across all frames while significantly reducing the frequency and quantity of messages in the bitstream
Solution Approach 2:
Multiple frames share a single film grain SEI message from the preceding I picture. The grain parameters are merged and applied across P and B pictures until the next I picture, reducing redundant message transmissions while maintaining consistency
3Measurement precision
If film grain simulation is performed in decoding order, then bit-accuracy is achieved, but compliance with H.264 display order requirement is violated
Solution Approach 1:
The system dynamically adapts its operation mode based on playback type. During normal playback, it processes frames in display order matching H.264 requirements. During trick mode playback, it switches to decoding order processing to maintain bit-accuracy, making the ordering flexible rather than fixed
Data Source
AI summary
There are provided methods and apparatus for film grain SEI message insertion for bit-accurate simulation in a video system. A method for simulating film grain in an ordered sequence includes the steps of providing film grain supplemental information corresponding to a plurality of intra coded pictures, and providing additional film grain supplemental information corresponding to inter coded pictures between consecutive intra coded pictures, in decode order. The inter coded pictures are selected based upon display order.