HDMI Source Apparatus EDID Caching and Sink State Detection
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Solution Overview
Problem
In HDMI systems, there is a delay in displaying video data due to the need for the source apparatus to reacquire Extended Display Identification Data (EDID) from the sink apparatus, leading to unnecessary power consumption when the video data received is not compatible, causing inefficiencies in video output.
Innovation Solution
A communication apparatus with detection units for Hot Plug Detect (HPD) and Transition Minimized Differential Signaling (TMDS) signals, allowing it to determine the connection state and video output status of the sink apparatus, enabling controlled video data transmission only when compatible, thereby reducing power consumption and delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the source apparatus continuously transmits video data to the sink apparatus, then the video output function is maintained, but power is wasted when the sink apparatus cannot display the transmitted video data
Solution Approach 1:
The source apparatus performs preliminary detection of the sink apparatus's output state through HPD and TMDS signals before transmitting video data. This preliminary action allows the system to avoid unnecessary video data transmission when the sink cannot display, thereby preventing power waste while maintaining reliable video output when needed.
2Adaptability or versatility
If the source apparatus reacquires EDID from the sink apparatus to ensure compatible video data transmission, then video compatibility is improved, but transmission delay increases
Solution Approach 1:
The source apparatus stores a copy of the EDID information obtained from the sink apparatus. When video data transmission is needed, the source apparatus uses this stored EDID copy to generate compatible video data immediately, avoiding the time-consuming process of reacquiring EDID while ensuring video compatibility.
3Productivity
If the source apparatus continuously monitors the sink apparatus state, then video transmission efficiency is improved, but system complexity increases
Solution Approach 1:
The sink apparatus generates HPD and TMDS signals that automatically indicate its output state. The source apparatus simply detects these self-generated signals from the sink to determine whether to transmit video data, eliminating the need for complex active monitoring mechanisms while improving video transmission efficiency.
Data Source
AI summary
A communication apparatus includes a communication unit that communicates with an external apparatus via communication lines conforming to HDMI standard, a first detection unit that determines whether a first signal is detected indicating that the communication unit and the external apparatus are connected, a second detection unit that determines whether a second signal is detected indicating that the external apparatus is in a state where the external apparatus displays video data transmitted from the communication unit, and a control unit that controls the communication unit to transmit the video data to the external apparatus if the first signal and the second signal are detected.