HDMI Audio Embedding for Signal Integrity

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Solution Overview

Problem

Current sound recording systems for digital and mirror-less single-lens reflex cameras often suffer from inadequate sound quality when recording video, as they typically require separate sound recording devices connected via analog interfaces, leading to signal degradation.

Innovation Solution

A sound recording apparatus that connects via HDMI to cameras and external devices, embedding microphone audio signals into the HDMI signal without processing the video image, ensuring high-quality audio output without degradation, even when the camera has only analog sound input terminals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a sound recording apparatus is connected to a backup image recording apparatus via analog connection, then compatibility with existing devices is improved, but audio signal quality deteriorates due to degradation

Engineering Contradiction:
ImprovecompatibilityVSAvoidaudio signal quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The sound recording apparatus acts as an intermediary device between the camera and backup image recording apparatus. It receives digital audio signals from the camera via HDMI, processes/embeds them into the HDMI signal stream, and transmits the combined signal to the backup recorder. This intermediary function enables digital audio transmission without direct analog connection, maintaining signal quality while ensuring compatibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces the analog mechanical connection system with a digital HDMI-based transmission system. Instead of using analog audio cables that cause signal degradation, the system embeds digital audio signals within the HDMI digital signal stream, substituting the analog transmission mechanism with a digital one that preserves audio quality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If audio signals are embedded in HDMI signal channels, then audio signal quality is improved by avoiding analog conversion, but channel allocation complexity increases when existing audio signals are present

Engineering Contradiction:
Improveaudio signal qualityVSAvoidchannel allocation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The channel allocation mechanism is made dynamic and adaptive. The sound recording apparatus automatically detects which audio channels are already occupied in the HDMI signal and dynamically selects appropriate channels for embedding the microphone audio signal. This dynamic adaptation resolves the allocation complexity by making the system flexible rather than fixed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs self-allocation of audio channels by automatically detecting the HDMI signal's current audio channel usage and selecting appropriate channels for embedding. The apparatus serves itself by autonomously managing channel allocation without requiring manual configuration or external intervention, thereby simplifying the overall system operation despite the underlying complexity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3125532B1Camera-connection-type sound recording apparatus
Publication Date: 2019.06.05 TEAC CORP
  • EP3125532B1 patent drawingFigure 1
  • EP3125532B1 patent drawingFigure 2
  • EP3125532B1 patent drawingFigure 3

AI summary

A sound recording apparatus is provided which is HDMI-connected to a camera and another device, which outputs a video image signal from the camera to the other device without processing, and which outputs to the other device, without degradation, an audio signal recorded separately from the camera. A sound recording apparatus is HDMI-connected to a camera and a backup image recording apparatus. The sound recording apparatus includes an HDMI receiver that receives an HDMI signal transmitted from the HDMI-connected camera, a controller that embeds an audio signal which is input from a microphone which is connected to the apparatus in an audio channel portion of the HDMI single, and an HDMI transmitter that outputs to the backup image recording apparatus the video image signal included in the HDMI signal and the audio signal embedded by the controller.