Video Decoder Skip Redundant SPS PPS Using SEI Flags
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Solution Overview
Problem
Existing video coding standards, such as H264, require unnecessary and time-consuming decoding of redundant Sequence Parameter Sets (SPS) and Picture Parameter Sets (PPS) across multiple Groups of Pictures (GOPs, as these parameters are often repeated and decoded expensively despite not changing.
Innovation Solution
A device and method for coding video data that inserts a message at the start of each GOP indicating whether the current SPS and PPS are identical to the previous GOP's, allowing decoders to skip decoding redundant units, using Supplemental Enhancement Information (SEI) messages compatible with the H264 standard.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SPS and PPS are decoded every time according to H264 standard, then decoding reliability is ensured, but decoding time and computational cost increase significantly
Solution Approach 1:
The encoder performs preliminary action by inserting a flag message before the SPS/PPS NAL units, indicating whether these parameter sets have changed compared to the previous GOP. This preliminary information allows the decoder to prepare appropriately and skip unnecessary decoding operations, resolving the contradiction between ensuring reliability through complete decoding and reducing time through selective decoding.
Solution Approach 2:
The system implements feedback by having the encoder transmit change information about SPS/PPS parameters to the decoder. This feedback mechanism enables the decoder to adapt its behavior based on whether the parameters have changed, allowing it to skip decoding when parameters are unchanged while still maintaining decoding reliability when changes occur.
2Adaptability or versatility
If redundant SPS and PPS data are transmitted and decoded, then compatibility with standard decoders is maintained, but processing efficiency decreases
Solution Approach 1:
The flag message acts as an intermediary element between the redundant SPS/PPS data and the decoder's processing logic. This intermediary provides the necessary information to enable efficient selective decoding while maintaining compatibility with standard H264 decoders, as the flag message is inserted in a way that does not violate standard compliance requirements.
Solution Approach 2:
The invention applies local quality by treating different parts of the bitstream differently: the flag message is always present and decoded, while the SPS/PPS NAL units are selectively decoded based on the flag information. This allows the system to maintain compatibility where needed while optimizing efficiency where possible, resolving the contradiction between adaptability and productivity.
Data Source
AI summary
The invention relates to a device for coding video data comprising means to code a video stream as groups of pictures, each group of pictures comprising at least one description unit relevant to the coding of the said group of pictures. According to the invention, the coding device comprises means to insert in the stream of data at least one message indicating whether the description unit of the current group of pictures is identical to the description unit relevant to the preceding group of pictures. The invention also relates to a device for decoding video data comprising means to decode a stream of data coded with a device according to one of the preceding claims. According to the invention, the decoding device comprisesmeans to analyze the said messages,means to decode the at least one next description unit if the said message indicates that this unit is different from the preceding description unit, otherwise, if it is identical, not to decode it.