Seamless Video Stream Switching via Bridging Frames
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Solution Overview
Problem
Current methods for switching between video streams, especially at low bit rates, often result in disruption and noticeable drift errors due to the lack of seamless and fast switching capabilities, particularly when switching between dissimilar streams or in low bit rate environments.
Innovation Solution
A method involving an intermediate switching stream with successive GOP sequences, including an initial I-frame and P-frames, that converges towards the destination stream, allowing for quick and seamless switching by matching the frame rate and bit rate of the destination stream, thereby minimizing drift errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If switching occurs on P-frames without matching references, then switching speed is improved, but visual artifacts and drift error increase
Solution Approach 1:
The patent prepares matching reference frames in advance by inserting bridging frames (S-frames) before the actual switching event. These bridging frames are generated ahead of time to ensure that when switching occurs, the decoder already has the necessary reference frames to maintain prediction accuracy, thus preventing drift error while enabling fast switching.
Solution Approach 2:
The patent introduces bridging frames (S-frames) as intermediary elements between the source stream and destination stream. These bridging frames act as mediators that bridge the gap between dissimilar streams, providing matching references to the decoder during the transition period and eliminating the need for exact reference matching at the moment of switching.
2Reliability
If I-frames are used for switching between dissimilar streams, then switching reliability is improved, but bit rate increases significantly
Solution Approach 1:
The patent uses bridging frames (S-frames) as intermediary elements that enable reliable switching between dissimilar streams without requiring full I-frames. These bridging frames contain the necessary reference information at a lower bit rate than complete I-frames, thus maintaining switching reliability while reducing the bit rate penalty.
Solution Approach 2:
The patent changes the frame type parameter from traditional I-frames to bridging frames (S-frames) for switching operations. This parameter change allows the system to maintain the reliability of frame-based switching while significantly reducing the bit rate requirement, as S-frames are more efficient than full I-frames.
3Quantity of substance
If switching occurs at low bit rates, then bandwidth efficiency is improved, but switching speed decreases and disruption increases
Solution Approach 1:
The patent performs preliminary preparation of bridging frames and reference frames before switching is needed. By pre-generating these frames and storing them in buffers, the system eliminates the need for complex frame generation during the switching event itself, thus maintaining fast switching speeds even at low bit rates where frame generation would otherwise be too slow.
Solution Approach 2:
The patent segments the switching process into multiple phases: preparation phase (where bridging frames are generated in advance), transition phase (where switching occurs quickly using pre-prepared frames), and stabilization phase (where normal decoding resumes). This segmentation allows the system to achieve fast switching at low bit rates by performing the computationally intensive frame generation during the preparation phase rather than during the critical transition phase.
4Object-generated harmful factors
If bridging frames are used for switching, then drift error is reduced, but bit rate increases due to unique S-frame requirements
Solution Approach 1:
The patent changes the frame type parameter from traditional I-frames to bridging frames (S-frames) for switching operations. This parameter change allows the system to maintain the reliability of frame-based switching while significantly reducing the bit rate requirement, as S-frames are more efficient than full I-frames.
Data Source
AI summary
The invention relates to a method (300, 310) of switching from a source encoded video stream (134) to a destination encoded video stream (108), and to an apparatus (100), a video platform (210) and a system (200) therefor. The method (300, 310) includes providing an intermediate switching stream (130) which is dependent upon the destination stream (108), the switching stream (130) including a plurality of successive GOP sequences, each GOP sequence including an initial l-frame and at least one successive P-frame. The method (300, 310) further includes switching from the source video stream (134) to the l-frame of a GOP sequence of the switching stream (130) and then switching from the switching stream (130) to the destination stream (108) such that the subsequent frames of the destination stream (108) can be decoded using the accumulated reference of the GOP sequence of the switching stream (130).