NAL Unit Marker Insertion for Bitstream Decoding
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Solution Overview
Problem
The processing of multimedia bitstreams conforming to the ISO Base Media File Format using the packet-oriented approach is inefficient due to increased hardware complexity and production costs, and poor error concealment capabilities, as decoders need to use counters and extra memory to identify NAL units without start code prefixes.
Innovation Solution
A method and apparatus that extract NAL units from multimedia bitstreams and generate a processed bitstream with unique markers, allowing decoders to easily locate NAL units by searching for these markers, thereby reducing hardware complexity and improving decoding performance and error concealment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the packet-oriented approach is used to pack NAL units without start code prefixes, then the bitstream compression efficiency is improved, but the decoder hardware complexity increases due to the need for counters and extra memory
Solution Approach 1:
The invention performs preliminary action by inserting start code prefixes into the bitstream during the encoding process. These prefixes are placed before each NAL unit to mark its boundary, enabling the decoder to identify NAL units without requiring complex counter mechanisms or extra memory, thus resolving the hardware complexity issue while maintaining compression efficiency
2Device complexity
If the packet-oriented approach is used without start code prefixes, then the bitstream format is simplified, but the error concealment performance deteriorates because it is difficult to skip error portions and locate the next NAL unit
Solution Approach 1:
The invention inserts start code prefixes as preliminary markers before each NAL unit during encoding. These prefixes serve as reliable delimiters that enable the decoder to easily identify NAL unit boundaries even when errors occur, allowing the decoder to skip error portions and locate the next valid NAL unit, thereby significantly improving error concealment performance
Data Source
AI summary
A method and apparatus for processing a multimedia bitstream are provided. The apparatus comprises a receive module, an extraction module, and a generation module. The receiving module receives the multimedia bitstream, wherein the multimedia bitstream comprises a plurality of NAL units. The extraction module extracts the NAL units from the multimedia bitstream. The generation module generates a processed bitstream comprising markers and NAL units. Each of the markers has a unique code. By doing so in future processing, a decoder or a decoding method can locate NAL units easily by searching for the corresponding marker.