Video Decoder Handling Mixed HDR SDR Segments
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Solution Overview
Problem
The existing technologies for handling high dynamic range (HDR) video images face challenges in decoding changes in time due to the lack of dynamic electro-optical transfer functions (EOTFs), leading to issues like bright glitches or invisibly dark regions when images with different EOTFs are not correctly interpreted by decoders.
Innovation Solution
A video decoder is designed to handle temporally successive images with pixel colors defined by dynamically changeable and fixed EOTFs, where dynamic metadata is transmitted less frequently and stored in memory prior to changes, allowing the decoder to apply the correct EOTF for each segment, ensuring accurate luminance reconstruction across different HDR and SDR segments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dynamic EOTF functions are transmitted for each image to enable accurate HDR decoding, then decoding accuracy is improved, but data transmission volume and processing complexity increase
Solution Approach 1:
The video stream is segmented into alternating HDR and SDR segments with clear boundary markers. The decoder segments the incoming data stream to identify segment type and apply appropriate decoding strategies for each segment, simplifying the overall decoding process while maintaining accuracy.
Solution Approach 2:
Boundary markers indicating HDR segment starts are transmitted in advance before the actual HDR content. This allows the decoder to prepare the appropriate EOTF functions and decoding parameters beforehand, ensuring accurate decoding without requiring complex real-time analysis of each image's encoding type.
2Adaptability or versatility
If HDR and SDR segments are interleaved in the video stream, then versatility and compatibility are improved, but decoding reliability deteriorates due to EOTF confusion
Solution Approach 1:
Boundary markers serve as intermediary signals that clearly delineate transitions between HDR and SDR segments. These markers act as mediators that guide the decoder in switching between different EOTF interpretations, preventing EOTF confusion and ensuring reliable decoding of interleaved segments.
Solution Approach 2:
The decoder dynamically switches between HDR and SDR decoding modes based on the boundary markers detected in the data stream. This dynamic adaptation allows the system to handle interleaved segments reliably by adjusting its interpretation of luma codes according to the current segment type.
3Device complexity
If luma codes are interpreted with fixed EOTF assumption, then device complexity is reduced, but image quality deteriorates with bright glitches or dark regions
Solution Approach 1:
The decoder applies different EOTF interpretation rules to different segments based on boundary marker identification. HDR segments receive dedicated EOTF functions while SDR segments use standard EOTF assumptions, ensuring each segment is decoded with the appropriate quality characteristics for its type.
Data Source
AI summary
Because there are currently probably more than necessary different HDR video coding methods appearing, it is expected that practical communicated HDR videos may in several future scenarios consist of a complicated mix of differently encoded HDR video segments, which may be difficult to decode unless one has our presently presented video decoder (341) arranged to decode a high dynamic range video consisting of temporally successive images, in which the video is composed of successive time segments (S1, S2) consisting of a number of temporally successive images (I1, I2) which have pixel colors, which pixel colors in different time segments are defined by having lumas corresponding to pixel luminances according to different electro-optical transfer functions (EOTF), wherein the images in some of the segments are defined according to dynamically changeable electro-optical transfer functions which are transmitted as a separate function for each temporally successive image, and wherein the images in other segments have lumas defined by a fixed electro-optical transfer function, of which the information is co-communicated in data packages (DRAM) which are transmitted less frequently than the image repetition rate, and wherein at least one of said data packages (DRAM) characterizing the electro-optical transfer function of the image pixel lumas after a moment of change (t1) between a first and a second segment is transmitted prior to the moment of change (t1); and similarly a corresponding encoder which composes the segmented video stream assuring that at least one correct package (DRAM) describing the EOTF according to which the lumas of a later video segment is coded is received by receivers before the change to a different HDR encoding method segment.