Reference Decoder CPB Timing for Seamless Video Stream Splicing
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Solution Overview
Problem
Existing video coding standards face challenges in seamless splicing, CPB buffer management, and timing adjustments for partial decoding of video streams, particularly in scenarios involving splicing, scalable bitstreams, and varying transmission conditions.
Innovation Solution
The proposed solution involves encoding video data streams with first and second timing information for complete and reduced versions, respectively, and managing CPB buffers using these timing cues, along with additional HRD timing information for bitrate interpolation and splice point management, ensuring seamless splicing by adjusting CPB removal times based on splicing conditions and stream concatenation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single set of CPB removal times is used for complete video streams, then decoder complexity is reduced, but adaptability to partial stream decoding and splicing scenarios deteriorates
Solution Approach 1:
The patent implements dynamic timing information that adapts based on decoding mode. The decoder selectively applies first timing information for complete streams or second timing information for partial streams/spliced streams based on detection of splice points and stream configuration, enabling the system to change its behavior dynamically rather than using a fixed approach
Solution Approach 2:
The patent segments the timing information into distinct first and second sets, where first timing information applies to complete video streams and second timing information applies to partial or spliced streams. This segmentation allows the decoder to handle different stream types with appropriate timing parameters without increasing overall system complexity
2Productivity
If timing information is optimized for complete video streams, then decoding efficiency is improved, but performance in spliced or partial stream scenarios deteriorates
Solution Approach 1:
The decoder dynamically selects between first and second timing information based on the stream type detected. For complete streams, first timing information provides optimal decoding efficiency, while for spliced or partial streams, second timing information ensures reliable buffer management and timing synchronization
Solution Approach 2:
The patent changes the timing parameters based on stream configuration. The decoder detects whether it is processing a complete or partial/stream-spliced video and adjusts the CPB removal times accordingly, using first timing information for complete streams and second timing information for spliced streams to maintain both efficiency and reliability
3Device complexity
If CPB buffer management uses fixed removal times, then buffer overflow prevention is simplified, but flexibility in handling varying transmission conditions deteriorates
Solution Approach 1:
The buffer management system dynamically adjusts CPB removal times based on transmission conditions and stream type. The decoder detects splicing points and stream configuration, then selectively applies first or second timing information to maintain both simplified buffer management and adaptability to varying conditions
Solution Approach 2:
The patent creates a universal buffer management approach that handles multiple scenarios (complete streams, partial streams, spliced streams, varying transmission conditions) through a single system that selects between first and second timing information based on detected conditions, eliminating the need for separate buffer management systems for each scenario
Data Source
AI summary
A video data stream having a video encoded thereinto and is described. It includes first timing information on first coded picture buffer, CPB, removal times to be applied at decoder side in case of buffering a complete version of the video data stream, and second timing information on second CPB removal times to be applied at decoder side for buffering a reduced version of the video data stream, differing from the video data stream by removal of a portion of the video data stream from the complete version of the video data stream. Corresponding video encoders, video decoders, network nodes, apparatuses for managing the coded picture buffer, CPB, of a video decoder, and apparatuses for splicing together video data streams are also referred to.