Digital Video Splice Artifact Removal via B-Frame Extraction
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Solution Overview
Problem
Low-end cable set-top boxes often display poor splices between video clips due to mismatched presentation times and incorrect reference frames, resulting in visual artifacts like macroblocking and green flashes, as they ignore transport layer discontinuity indicators and decode B-frames using an incorrect reference frame.
Innovation Solution
A low-overhead method is introduced to improve splice visual quality by calculating the length of MPEG data to be inserted between clips and removing B-frames that reference non-existent I-frames, involving the insertion of stuffing packets to align presentation time stamps and dynamic creation of MPEG data to remove unwanted B-frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the MPEG decoder ignores transport layer discontinuity indicators and decodes B-frames using incorrect reference frames, then the decoding process continues without interruption, but visual artifacts such as macroblocking and green flashes occur
Solution Approach 1:
The patent extracts and removes the problematic B-frames from the video stream at the splice point. By identifying and taking out these specific frames that cause visual artifacts, the system maintains decoding continuity while eliminating macroblocking and green flash artifacts, thus resolving the contradiction between productivity and visual quality.
Solution Approach 2:
The patent performs preliminary actions by pre-calculating the number of stuffing packets needed and pre-identifying B-frames that need removal before the actual splice occurs. This preparation allows the decoder to handle the transition smoothly without interruption, maintaining both decoding continuity and visual quality.
2Manufacturing precision
If stuffing packets are inserted to align presentation time stamps, then visual quality of splices improves, but the complexity of the transport stream increases
Solution Approach 1:
The patent changes the temporal parameters of the transport stream by inserting a calculated number of stuffing packets. This parameter adjustment aligns the presentation time stamps of the first video clip with the second video clip, achieving proper time synchronization without requiring complex remapping operations, thus improving visual quality while managing stream complexity.
3Manufacturing precision
If full remapping of video clip time bases is performed, then splice visual quality improves, but processing time and computational resources increase
Solution Approach 1:
The patent applies partial action by performing only the necessary time alignment adjustments rather than full remapping of video clip time bases. By inserting a specific number of stuffing packets and removing only the problematic B-frames, the system achieves sufficient time base alignment for quality splices without the computational overhead and time cost of complete remapping operations.
Data Source
AI summary
A digital splicing process includes calculating the length of data to be inserted into a transport stream between first and second video clips; and removing B-frames in the second clip that reference non-existent I-frames without replacing the removed B-frames with new B-frames.