Video Decoding Apparatus Macroblock Parsing and Reconstruction
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Solution Overview
Problem
Video decoding apparatuses face inefficiencies when handling encoded video bitstreams with Flexible Macroblock Order (FMO), as parsing efficiently requires bitstream order while reconstruction is more efficient in raster scan order, leading to increased latency and memory access bandwidth issues.
Innovation Solution
A video decoding apparatus with a parsing unit that stores macroblock information in bitstream order and generates line control information with pointers to access the information in raster scan order, allowing both parsing and reconstruction to operate efficiently without reordering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the parser processes macroblocks in bitstream order to maintain consistent context for entropy decoding, then parsing efficiency is improved, but the reconstruction pipeline cannot efficiently access macroblocks in raster scan order, increasing memory bandwidth requirements and processing latency
Solution Approach 1:
The patent segments the macroblock processing into two independent data structures: one organized in bitstream order for parsing and another in raster scan order for reconstruction. This segmentation allows each pipeline stage to access macroblocks in its optimal order without forcing the other stage to adapt, thereby maintaining parsing efficiency while reducing memory bandwidth consumption during reconstruction.
Solution Approach 2:
The patent introduces an intermediary data structure (the second data structure organized in raster scan order) that mediates between the parser operating on bitstream-ordered data and the reconstruction pipeline requiring raster scan-ordered access. This intermediary eliminates the need for the reconstruction pipeline to access macroblocks in bitstream order, reducing memory bandwidth requirements and processing latency.
2Reliability
If Flexible Macroblock Order (FMO) is used to improve error resilience in lossy transmission environments, then reliability is improved, but the decoding apparatus complexity increases due to the mismatch between bitstream order and raster scan order
Solution Approach 1:
The patent applies segmentation by maintaining separate data structures for different processing stages, allowing FMO to be supported without increasing decoding complexity. The first data structure handles bitstream order for error-resilient FMO decoding, while the second data structure handles raster scan order for efficient reconstruction, eliminating the need for complex reordering logic in the reconstruction pipeline.
Solution Approach 2:
The patent creates a copy of macroblock information in a second data structure organized in raster scan order, based on the original bitstream-ordered data structure. This copying approach allows the reconstruction pipeline to work with pre-organized data without requiring complex reordering operations, thereby supporting FMO while maintaining manageable decoding apparatus complexity.
3Productivity
If macroblocks are stored and accessed in bitstream order during parsing, then parsing efficiency is improved, but random access to macroblocks for reconstruction becomes less efficient, increasing latency
Solution Approach 1:
The patent segments macroblock storage into two distinct data structures with different organizational schemes. The first data structure maintains bitstream order for efficient parsing, while the second data structure maintains raster scan order for efficient reconstruction access. This segmentation eliminates the trade-off by providing dedicated storage for each processing stage's access pattern requirements.
Solution Approach 2:
The patent performs preliminary organization of macroblock information into a second data structure in raster scan order during the parsing stage. This preliminary action ensures that when the reconstruction pipeline needs to access macroblocks, they are already organized in the optimal order, eliminating the need for time-consuming reordering operations and reducing reconstruction latency.
Data Source
AI summary
A video decoding apparatus for decoding an encoded video bitstream having frames of video data encoded in rows of macroblocks. The video decoding apparatus comprises a parsing unit configured to receive the encoded video bitstream and to interpret the encoded video bitstream to generate items of macroblock information to be used for reconstructing the video frames of video data. The parsing unit is configured to store the items of macroblock information in a memory in bitstream order. The video decoding apparatus further comprises a line control unit configured to generate line control information associated with each row of macroblocks, the line control information comprising a sequence of pointers to the items of macroblock information stored in the memory, such that sequentially reading the sequence of pointers accesses the items of macroblock information in raster scan order. The line control information is stored in said memory in association with said items of macroblock information. A reconstruction pipeline is configured to reconstruct the frames of video data with reference to the line control information.