Frame Synchronous HDMI Metadata Transmission for HDR Video Transitions
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Solution Overview
Problem
Existing HDMI systems experience image distortion when switching between standard dynamic range (SDR) and high dynamic range (HDR) video formats due to asynchronous metadata transmission, leading to mismatches in video data processing and metadata application.
Innovation Solution
Implementing a frame synchronous transmission window (FSTW) for auxiliary video information (AVI) InfoFrames, DRange and Mastering (DRAM) InfoFrames, and HDR dynamic metadata extended (HDR DME) InfoFrames, ensuring metadata is applied immediately after reception during the vertical blanking interval, aligning with the frame accurate packet area (FAPA) timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If metadata is transmitted asynchronously during HDMI video transmission, then the HDMI interface can maintain backward compatibility and flexible data transmission, but image distortion occurs during transitions between SDR and HDR video formats due to mismatches in metadata application timing
Solution Approach 1:
The patent applies preliminary action by transmitting metadata in advance during the vertical blanking interval (VBI) before the active video display begins. This ensures that the receiving device has the metadata ready and synchronized with the corresponding video frame, eliminating timing mismatches that cause image distortion during SDR-HDR transitions while maintaining HDMI interface compatibility
2Measurement precision
If HDR DME InfoFrames are transmitted during the frame accurate packet area (FAPA) period, then frame-synchronous processing is achieved for dynamic HDR metadata, but the transmission timing becomes precisely constrained reducing flexibility in InfoFrame scheduling
Solution Approach 1:
The patent segments the video signal transmission into distinct time periods: the vertical blanking interval (VBI) for metadata transmission and the active video interval for picture data transmission. By placing HDR DME InfoFrames specifically within the FAPA period of the VBI, the patent achieves frame-synchronous processing with precise timing control while keeping the active video transmission flexible and unconstrained
3Ease of operation
If AVI InfoFrames and DRAM InfoFrames are transmitted without specific timing requirements, then transmission flexibility is maintained, but synchronization with video frames cannot be guaranteed leading to visual artifacts during format switching
Solution Approach 1:
The patent applies preliminary action by requiring that AVI InfoFrames and DRAM InfoFrames be transmitted during the vertical blanking interval (VBI) before the corresponding active video interval begins. This preliminary transmission ensures that metadata is synchronized with the video frame it describes, eliminating visual artifacts during format transitions while maintaining transmission flexibility within the VBI period
Data Source
AI summary
An apparatus for use in a high-definition media interface (HDMI) source device includes an HDMI interface for transmitting video data and metadata to a sink device. The apparatus is configured to encode the metadata in an auxiliary video information (AVI) information frame (InfoFrame). The apparatus is further configured to transmit the AVI InfoFrame during a frame synchronous transmission window (FSTW) of the video data, wherein the FSTW begins during a video blanking interval (VBI) of the video data, on a first video blank pixel that immediately follows a last active video pixel of a preceding video frame or video field and ends a predetermined number of video lines after a start of the VBI.