Subtitle Luminance Adjustment in HDR Video Transmission
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Solution Overview
Problem
In digital video broadcasting, subtitle information transmitted over high dynamic range (HDR) images with high contrast ratios causes visual fatigue due to unsuitable luminance levels, as existing methods do not effectively adjust subtitle luminance to match the background image.
Innovation Solution
A transmission device generates a video stream with luminance level adjustment information, including maximum, minimum, and average luminance values, which is inserted into the video and subtitle streams, allowing the reception side to adjust subtitle luminance levels accordingly, reducing visual fatigue and maintaining the HDR effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If subtitle information is transmitted as bitmap data without luminance adjustment, then the transmission process is simple, but visual fatigue occurs due to unsuitable luminance levels on HDR images
Solution Approach 1:
The patent applies parameter changes by transmitting luminance level adjustment information (maximum luminance value, minimum luminance value, average luminance value) along with the subtitle stream. This enables the reception device to dynamically adjust the luminance levels of subtitles according to the background image characteristics, resolving the contradiction between simple transmission and visual comfort.
2Object-affected harmful factors
If subtitle luminance is adjusted to match HDR background images, then visual fatigue is reduced, but the transmission system becomes more complex
Solution Approach 1:
The patent segments the luminance adjustment information into distinct parameters (maximum luminance value, minimum luminance value, average luminance value) that can be independently transmitted and processed. This segmentation allows the reception device to perform targeted luminance adjustment without requiring complete system redesign, thus managing complexity while achieving visual comfort.
Solution Approach 2:
The patent introduces luminance level adjustment information as an intermediary element between the subtitle stream and the display output. This intermediary carries the necessary adjustment parameters without fundamentally changing the subtitle transmission format, thereby reducing system complexity while enabling adaptive luminance control.
3Object-affected harmful factors
If luminance level adjustment information is added to the subtitle stream, then subtitle luminance can be optimized for HDR images, but the data transmission load increases
Solution Approach 1:
The patent uses parameter changes by encoding luminance adjustment information as compact numerical values (maximum luminance value, minimum luminance value, average luminance value). These parameters are transmitted efficiently and allow for precise luminance control without requiring large amounts of data, thus minimizing the increase in transmission load while achieving optimal visual comfort.
Data Source
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AI summary
The reception side is to be enabled to perform subtitle luminance level adjustment in a preferred manner. A video encoder generates a video stream including image data. A subtitle encoder generates a subtitle stream including subtitle information. An adjustment information insertion unit inserts luminance level adjustment information for adjusting the luminance level of a subtitle, into the video stream and/or the subtitle stream. A transmission unit transmits a container in a predetermined format containing the video stream and the subtitle stream.