Transcoder Extracting Motion Estimation for Video Format Conversion
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Solution Overview
Problem
The need to convert existing MPEG-2 compressed video bit-streams into the more efficient H.264 standard for modern video applications, while maintaining compatibility and video quality, is hindered by the complexity and inefficiency of traditional re-encoding methods which involve full decoding and re-encoding processes.
Innovation Solution
A transcoding method that extracts and reuses motion estimation information, quantization factors, and coding modes from the MPEG-2 bit-stream to construct an H.264 bit-stream, avoiding costly motion estimation and ensuring efficient bit-rate adaptation, image resolution modification, and frame rate reduction, thereby simplifying the transcoding process and reducing computational power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional full decoding and re-encoding is used for transcoding, then complete format conversion is achieved, but system complexity and computational power requirements increase significantly
Solution Approach 1:
The patent extracts and reuses motion estimation information, quantization factors, and coding modes directly from the MPEG-2 bit-stream without performing full decoding and re-encoding. This extraction approach maintains format conversion capability while significantly reducing system complexity by avoiding redundant computational steps.
Solution Approach 2:
The patent performs preliminary extraction of motion estimation information and other encoding parameters from the input bit-stream before the actual transcoding process. This preliminary action allows the system to reuse previously computed data, reducing the computational burden during the conversion phase and lowering overall system complexity.
2Adaptability or versatility
If traditional full decoding and re-encoding is used for transcoding, then complete format conversion is achieved, but computational power requirements increase by at least one order of magnitude
Solution Approach 1:
The patent extracts motion estimation information, quantization factors, and coding modes from the MPEG-2 bit-stream and reuses them in the H.264 encoding process. This extraction method maintains complete format conversion capability while reducing computational power requirements by at least one order of magnitude, as the most expensive operations are avoided.
Solution Approach 2:
The patent changes the approach from recomputing all encoding parameters to selectively extracting and adapting existing parameters from the source bit-stream. By modifying how parameters are obtained (from computation to extraction), the system maintains conversion capability while dramatically reducing power consumption.
3Manufacturing precision
If motion estimation is performed during transcoding, then accurate motion compensation is achieved, but processing time and computational cost increase significantly
Solution Approach 1:
The patent performs motion estimation in advance during the MPEG-2 encoding phase, and then extracts and reuses the resulting motion vectors during transcoding. This preliminary action ensures accurate motion compensation is achieved while avoiding the time-consuming re-computation of motion estimation during the transcoding process.
Solution Approach 2:
The patent copies motion estimation information (motion vectors) from the MPEG-2 bit-stream and reuses it in the H.264 encoding process. This copying approach maintains motion compensation accuracy while significantly reducing processing time, as the expensive motion estimation operation is performed only once in the source encoding phase.
Data Source
AI summary
Transcoder apparatus for transcoding an input video bit-stream having a first encoding profile (e.g., MPEG-2) into an output video bit-stream having a second encoding profile (e.g., H.264), the first encoding profile including motion estimation information, the apparatus including: a front-end for extracting the motion estimation information from the input video bit-stream, and a back-end for constructing the output bit-stream. The front-end and the back-end of the apparatus are interconnected (e.g., via a buffer) to pass the motion estimation information from the front-end to the back-end, thereby avoiding motion estimation in constructing the output bit-stream at the apparatus back-end.