Video Stream Anchor Frames for Seamless Resolution Switching
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Solution Overview
Problem
Multi-user video conferencing systems face quality degradation during resolution changes due to the need to transmit keyframes, which increases bandwidth consumption and causes annoying quality fluctuations for participants.
Innovation Solution
Each encoding client transmits video streams with multiple resolutions, including a non-displayed anchor frame that can be used with reference frame scaling to change resolutions without requiring keyframes, thereby avoiding increased bandwidth usage during resolution changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If keyframes are transmitted during resolution changes, then resolution switching is enabled, but bandwidth consumption increases and quality degradation occurs
Solution Approach 1:
The video stream is segmented into multiple resolution layers (base layer and enhancement layers). The base layer contains essential video information that can be decoded independently, while enhancement layers provide additional detail. This segmentation allows receivers to switch between resolutions by selectively decoding different layers without requiring complete keyframe retransmission, thereby reducing bandwidth consumption during resolution changes.
Solution Approach 2:
The patent introduces a temporal dimension to resolution switching by using anchored frames that span multiple time periods. Instead of switching resolutions within a single time period (which requires keyframes), the system anchors resolution changes across time boundaries, allowing smooth transitions by referencing stable anchor points from previous periods. This dimensional approach eliminates the need for bandwidth-intensive keyframe transmission during resolution changes.
2Adaptability or versatility
If keyframes are transmitted during resolution changes, then resolution switching is enabled, but quality fluctuations occur for participants
Solution Approach 1:
By segmenting the video stream into base and enhancement layers with anchored frames, the patent ensures that resolution changes occur smoothly within each layer rather than causing abrupt quality fluctuations. The base layer provides a stable foundation that maintains consistent quality, while enhancement layers adapt to resolution changes without disrupting the overall video quality experience for participants.
Solution Approach 2:
The patent performs preliminary encoding of anchored frames at multiple resolutions during normal operation. These pre-encoded anchored frames are stored and readily available when resolution changes are needed. By having these reference frames prepared in advance across different resolutions, the system can switch resolutions immediately without quality degradation, eliminating the need for on-the-fly keyframe generation that causes quality fluctuations.
3Adaptability or versatility
If multiple resolution streams are transmitted, then scalability is improved, but data amount increases
Solution Approach 1:
The patent merges multiple resolution streams into a single scalable bitstream by combining base layer and enhancement layers. Instead of transmitting separate independent streams for each resolution, the system combines them into one unified stream where the base layer is transmitted once and enhancement layers add incremental detail. This merging reduces the total data amount while maintaining scalability, as receivers can selectively decode only the portions they need based on their capabilities and network conditions.
Solution Approach 2:
The patent implements a nested structure where enhancement layers are embedded within the base layer framework. The base layer contains essential video information that can be decoded independently, while enhancement layers are nested within and reference the base layer. This nested organization allows the system to provide multiple resolution levels from a single encoded structure, improving scalability without proportionally increasing data transmission, as lower-resolution receivers can discard enhancement layers while higher-resolution receivers utilize them.
Data Source
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AI summary
An encoded video stream (1100) that includes a plurality of first- resolution frames (PL) and a plurality of second-resolution frames(PM, PH) is transmitted from an encoding client to a first remote computing system. A first-resolution non-displayed anchor frame (G) is also transmitted from the encoding client to the first remote computing system in the encoded video stream. The encoding client receives, from the first remote computing system, a request to change resolution. In response to receiving the request to change resolution, the encoding client transmits, to the first remote computing system in the encoded video stream, a set of frames that are encoded relative to the first-resolution non-displayed anchor frame.