Delayed Duplicate I-Picture for Video Decoder Refresh
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Solution Overview
Problem
Network-based video applications face bandwidth constraints and latency issues due to periodic IDR transmissions, leading to packet loss and decreased video quality, as existing techniques like adaptive intra refresh and gradual decoder refresh either cause error propagation or reduce video quality.
Innovation Solution
Implementing delayed duplicate I-pictures (DDIs) that are transmitted non-real-time and used as reference pictures for decoder refresh, allowing subsequent P-pictures to be encoded using these references, thereby reducing peak bandwidth and latency while maintaining video quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic IDR transmissions are used for decoder refresh, then video quality is maintained and error propagation is stopped, but peak bandwidth increases and latency increases causing packet loss
Solution Approach 1:
The patent creates a delayed duplicate I-picture (DDI) in advance before the actual IDR is needed. This DDI is generated by duplicating a previous I-picture and delaying its transmission until just before the decoder refresh point, allowing the actual IDR to be smaller and transmitted more efficiently, thus reducing peak bandwidth while maintaining video quality.
2Reliability
If periodic IDR transmissions are used for decoder refresh, then error propagation is stopped, but latency increases causing frame skipping
Solution Approach 1:
The DDI is prepared in advance but transmitted with delayed timing control. The transmission is scheduled to arrive just before the decoder refresh point, minimizing the actual latency impact on real-time playback while still providing the error recovery capability when needed.
3Quantity of substance
If adaptive intra refresh is used to reduce IDR bandwidth, then peak bandwidth is reduced, but error propagation occurs when refreshed blocks refer to non-refreshed blocks
Solution Approach 1:
The DDI acts as an intermediary reference picture. Instead of having P-pictures reference potentially error-prone previous pictures directly, the DDI serves as a clean, error-free intermediate reference that P-pictures can safely reference, preventing error propagation while still allowing progressive refresh with reduced bandwidth.
4Reliability
If gradual decoder refresh is used to prevent error propagation, then error propagation is reduced, but bit-rate increases and video quality decreases
Solution Approach 1:
The patent creates a copy of a previous I-picture (the DDI) that can be used as a reference without the high bit-rate overhead of transmitting a full I-picture at every refresh point. This copied reference picture provides error propagation control similar to gradual refresh but with more efficient bandwidth utilization.
Data Source
AI summary
A method is provided that includes receiving pictures of a video sequence in a video encoder, and encoding the pictures to generate a compressed video bit stream that is transmitted to a video decoder in real-time, wherein encoding the pictures includes selecting a picture to be encoded as a delayed duplicate intra-predicted picture (DDI), wherein the picture would otherwise be encoded as an inter-predicted picture (P-picture), encoding the picture as an intra-predicted picture (I-picture) to generate the DDI, wherein the I-picture is reconstructed and stored for use as a reference picture for a decoder refresh picture, transmitting the DDI to the video decoder in non-real time, selecting a subsequent picture to be encoded as the decoder refresh picture, and encoding the subsequent picture in the compressed bit stream as the decoder refresh picture, wherein the subsequent P-picture is encoded as a P-picture predicted using the reference picture.