Media Device State Detection with HDMI DDC Bus Probing
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Solution Overview
Problem
Conventional media device state detection techniques based on HDMI port monitoring are unreliable due to inconsistent integration of CEC and DDC protocols across different manufacturers and models, making it difficult to determine the operational state of media devices like TVs, especially when they are in low power consumption modes.
Innovation Solution
A method that utilizes the DDC bus of the HDMI port to send a probe message and detects the operational state by monitoring for activity gaps, relying on the I2C electrical subsystem to acknowledge the message, regardless of upper layer protocol implementation, while employing a communication collision avoidance algorithm to prevent interference with other devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CEC and DDC protocols are used for media device state detection, then device state can be detected, but reliability deteriorates due to inconsistent integration across manufacturers and models
Solution Approach 1:
The patent extracts the detection mechanism from the upper layer CEC/DDC protocols and implements it directly at the I2C electrical subsystem level. By sending probe messages through the I2C bus infrastructure that all HDMI implementations must have, the system bypasses manufacturer-specific protocol variations and achieves reliable detection across diverse devices.
Solution Approach 2:
The patent introduces an intermediary approach by using the I2C bus as a universal communication layer between the meter and media device. This intermediary layer sits below the variable CEC/DDC protocols, providing a consistent interface that works across all HDMI implementations regardless of upper layer protocol support.
2Measurement precision
If probe messages are sent on the DDC bus to detect device state, then operational state detection is enabled, but communication collisions may occur with other devices
Solution Approach 1:
The patent implements dynamic probing by monitoring the DDC bus for activity gaps before sending probe messages. The system adaptively adjusts its probing behavior based on real-time bus conditions, sending probes only when the bus is idle for a threshold duration, thereby avoiding collisions with other devices while maintaining detection accuracy.
Solution Approach 2:
The system uses feedback from bus activity monitoring to control probe message transmission. By continuously watching for DDC bus activity and using this feedback to determine when to send probes, the system ensures accurate state detection while preventing interference with other HDMI devices sharing the bus.
Data Source
AI summary
Example methods, apparatus, systems and articles of manufacture (e.g., physical storage media) to detect an operational state (such as an on/off state) of a media device are disclosed herein. Disclosed example apparatus are to monitor for activity on a first bus of an (HDMI) port of the media device. Disclosed example apparatus are also to inject a message with a first address on the first bus in response to detection of no activity on the first bus for at least a threshold duration. Disclosed example apparatus are further to detect the operational state of the media device based on whether a response to the message is received on the first bus.