Video Signal Dynamic Range Switching With Luminance Limiting
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Solution Overview
Problem
Existing video transmission and reception systems struggle with seamless switching between different luminance dynamic ranges, such as standard dynamic range (SDR) and high dynamic range (HDR), leading to potential display errors and inappropriate luminance levels during transitions.
Innovation Solution
A method and apparatus that generate and receive video signals with limited luminance levels during transitions, using transfer characteristics information to control luminance dynamic range switching at frame or random access unit accuracy, and include notification signals for smoother transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If video signals switch between different luminance dynamic ranges (SDR and HDR), then the system can support both legacy and advanced display standards, but display errors and inappropriate luminance levels occur during transitions
Solution Approach 1:
The transmission apparatus provides advance notification of upcoming luminance dynamic range switching through notification signals sent before the actual transition. This allows the reception apparatus to prepare in advance by adjusting its internal settings and buffering mechanisms, ensuring smooth transitions without display errors or luminance mismatches when the switch occurs.
Solution Approach 2:
The system incorporates notification signals that convey information about the upcoming luminance dynamic range change from the transmission apparatus to the reception apparatus. This feedback mechanism enables the reception apparatus to anticipate and prepare for the transition, maintaining display reliability and avoiding errors during the switching process.
2Speed
If luminance dynamic range switching is implemented without signal level limitation, then transition speed is fast, but display errors and inappropriate luminance levels occur
Solution Approach 1:
The transmission apparatus limits signal levels to a predetermined range in advance during the transition period, before the actual luminance dynamic range switching completes. This preliminary limitation prevents inappropriate luminance levels from causing display errors while still allowing the transition to proceed at an acceptable speed, as the limitation is applied temporarily only during the transition phase.
3Measurement precision
If notification signals are provided for luminance dynamic range switching, then switching accuracy is improved, but transmission signal complexity increases
Solution Approach 1:
The notification signals are integrated into the existing video transmission stream, utilizing available signal channels and protocols. Rather than adding a completely separate communication system, the notification is embedded within the transmission signal structure itself, allowing the same signal infrastructure to serve both the video content and the switching notification functions, thereby minimizing the increase in overall system complexity.
Data Source
AI summary
A video transmission method according to the present disclosure includes: generating a transmission signal including, in a time series, first video data having a first luminance dynamic range and second video data having a second luminance dynamic range wider than the first luminance dynamic range; and transmitting the transmission signal generated. In the generating of the transmission signal, a signal level corresponding to a luminance value is limited to a value lower than a limit value that is predetermined, in a transition period provided for switching from one of the first video data and the second video data to the other.