MPEG Transcoding by Macroblock Metadata Re-Encoding
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Solution Overview
Problem
The existing MPEG-2 to MPEG-4 transcoders require significant processing resources as they need to fully decode and re-encode, due to differences in standards between MPEG-2 and MPEG-4, which are not compatible in terms of code modes and motion vectors.
Innovation Solution
A method and apparatus that decode an MPEG-2 stream and use the derived information to partially re-encode it into an MPEG-4 stream, maintaining picture types and structures, and determining re-encoding modes based on metadata to reduce processing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If full decoding and re-encoding is performed to ensure compatibility between MPEG-2 and MPEG-4 standards, then encoding accuracy is improved, but processing complexity and resource consumption increase significantly
Solution Approach 1:
The patent applies partial action by performing only selective re-encoding of specific macroblocks that require format conversion, rather than fully re-encoding the entire video stream. The encoder identifies and processes only those blocks needing MPEG-4 specific partitioning, leaving other blocks in their original MPEG-2 encoded form, thus reducing overall processing complexity while maintaining encoding accuracy where needed.
Solution Approach 2:
The patent segments the video stream into individual macroblocks and processes them differently based on their encoding requirements. Each macroblock is evaluated independently to determine whether it needs full re-encoding or can be directly copied from the MPEG-2 stream, allowing selective application of the complex MPEG-4 encoding process only where necessary.
2Adaptability or versatility
If full re-encoding is performed to convert MPEG-2 to MPEG-4 format, then format compatibility is improved, but processing time increases
Solution Approach 1:
The patent performs partial re-encoding only on macroblocks that require MPEG-4 format conversion, rather than processing the entire video stream. This selective approach maintains format compatibility for necessary blocks while significantly reducing the total processing time by avoiding redundant re-encoding of compatible blocks.
Solution Approach 2:
The patent performs preliminary analysis of the MPEG-2 stream to identify macroblocks that require format conversion before initiating the re-encoding process. This preliminary identification allows the system to prepare only the necessary blocks for conversion, reducing overall processing time by avoiding unnecessary analysis and encoding of already compatible blocks.
3Productivity
If decoded information is re-used in re-encoding to speed processing, then processing speed is improved, but compatibility between different MPEG standards deteriorates
Solution Approach 1:
The patent applies local quality by re-using decoded information selectively for specific macroblocks where it remains valid, while performing full re-encoding for blocks that require MPEG-4 specific processing. This allows the system to maintain high processing speed for compatible blocks while ensuring standard compatibility for blocks that need format conversion.
Solution Approach 2:
The patent partially re-uses decoded information from the MPEG-2 stream for macroblocks that do not require format conversion, while performing complete re-encoding for blocks that need MPEG-4 compatibility. This selective approach maintains processing speed benefits where applicable while ensuring standard compatibility where required.
4Adaptability or versatility
If full decoding to baseband is performed to enable MPEG-4 encoding, then encoding flexibility is improved, but processing resources are consumed excessively
Solution Approach 1:
The patent performs partial decoding only for macroblocks that require MPEG-4 format conversion, rather than fully decoding the entire video stream to baseband. This selective decoding approach maintains encoding flexibility for necessary blocks while significantly reducing the processing resources required by avoiding redundant decoding of already compatible blocks.
Solution Approach 2:
The patent segments the video processing into individual macroblock operations, decoding and re-encoding only those blocks that require format conversion. This segmentation allows the system to maintain encoding flexibility where needed while minimizing processing resource consumption by avoiding unnecessary full-stream decoding.
Data Source
AI summary
A system is configured to transcode a first MPEG stream to a second MPEG stream. The system includes a first MPEG decoder capable of decoding the first MPEG stream and a second MPEG encoder capable of producing the second MPEG stream. The second MPEG encoder is configured to maintain a decoded picture type of I, P, or B. The second MPEG encoder is also configured to maintain a decoded picture structure of frame or field, identify a metadata per each macroblock (MB) of an MB pair of the first MPEG stream, and determine whether to re-encode the MB into the second MPEG stream using one of a frame or a field mode based on the identified metadata. The second MPEG encoder is further configured to re-encode the MB pair into the second MPEG stream using one of the frame or the field mode based on the identified metadata.