PCM Coded Block Split Signaling for Video Encoding Efficiency
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Solution Overview
Problem
In video encoding devices, PCM data from successive I_PCM CUs within a CTU cannot be efficiently multiplexed into a bitstream due to the need for repeated processes of outputting non-output symbols and resetting the encoding engine, leading to inefficiencies in transmission.
Innovation Solution
A video encoding device with a PCM determiner that sets the ctu_pcm_flag syntax to indicate whether all image blocks in a CTU are PCM blocks, allowing the multiplexing of PCM data without encoding the cu_split_flag syntax when all blocks are PCM, thus eliminating the need for intermediate entropy encoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If I_PCM mode headers are inserted between successive PCM data blocks for encoding, then each block can be individually encoded, but the encoding engine must repeatedly output non-output symbols and reset, reducing transmission efficiency
Solution Approach 1:
The patent merges multiple I_PCM CUs into a single I_PCM CU by removing internal boundaries. When all CUs in a CTU are I_PCM type, the patent combines them into one unified I_PCM CU, eliminating the need for multiple I_PCM mode headers and the associated encoding engine resets. This merging approach maintains encoding correctness while significantly improving multiplexing efficiency by allowing continuous PCM data transmission without intermittent processing interruptions.
2Manufacturing precision
If cu_split_flag syntax is encoded for each CU to indicate splitting pattern, then coding precision is maintained, but when all blocks are PCM, this creates redundant data increasing bitstream length
Solution Approach 1:
The patent extracts and removes redundant cu_split_flag syntax from the bitstream when all CUs in a CTU are of I_PCM type. By identifying that the splitting pattern information is unnecessary when all blocks use PCM encoding, the patent eliminates this redundant data, reducing bitstream length while preserving sufficient coding precision through the remaining necessary syntax elements.
3Reliability
If repeated engine reset processes are performed for successive I_PCM CUs, then each CU can be properly encoded, but transmission time and processing overhead increase
Solution Approach 1:
The patent performs preliminary determination of the I_PCM flag at the CTU level before encoding individual CUs. By checking whether all CUs in a CTU are I_PCM type in advance, the patent can set the I_PCM flag once at the beginning, allowing the encoding engine to process all successive I_PCM CUs without repeated resets. This preliminary action maintains encoding accuracy while eliminating time-consuming repeated reset operations.
Data Source
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AI summary
Although a video encoding device multiplexes ctu_pcm_flag syntax indicating whether all image blocks belonging to a coding tree unit as a set of image blocks are PCM blocks, at the top of the coding tree unit, when all image blocks belonging to the coding tree unit are PCM blocks, at least cu_split_flag syntax indicative of the splitting pattern of the coding tree unit is not multiplexed to transmit PCM data efficiently.