Audio Decoder DRC Profile Selection for Loudness-Adjusted Playback

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing audio signal processing technologies face challenges in maintaining high-quality and intelligibility across a broad range of rendering devices with different capabilities and environments, as they often fail to adapt dynamic range appropriately, leading to distortion or inaudibility.

Innovation Solution

The method involves embedding multiple Dynamic Range Control (DRC) profiles within audio frames, allowing an audio decoder to select the appropriate profile for the specific rendering mode, ensuring high-quality playback without distortion by adjusting loudness levels based on dynamic range compression curves and metadata.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single fixed dynamic range is used in audio encoding, then the encoding process is simple, but the audio quality deteriorates on devices with different rendering capabilities and in different listening environments

Engineering Contradiction:

Improveadaptability to different rendering devices and environmentsVSAvoidcomplexity of encoding process

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The audio encoding process is segmented into multiple versions with different dynamic range characteristics. Instead of encoding a single version, the system creates multiple encoded versions (e.g., different DRC profiles) that can be selected based on the playback device capabilities and listening environment, thereby resolving the contradiction between adaptability and encoding simplicity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The encoding system transitions from a static single-version approach to a dynamic multi-version approach. The encoder can adaptively select or generate appropriate dynamic range profiles based on metadata about the playback device and environment, enabling the system to be versatile without requiring complex real-time processing at playback

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If dynamic range is expanded to maintain audio quality on high-end devices, then audio fidelity is improved, but distortion and inaudibility occur on devices with limited rendering capabilities or in noisy environments

Engineering Contradiction:

Improveaudio fidelityVSAvoiddistortion and inaudibility

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

Multiple encoded versions with different dynamic range parameters are created during encoding. Each version has optimized parameters (such as different compression ratios, threshold levels, or gain structures) suitable for specific device capabilities and environmental conditions. The playback system selects the appropriate version based on detected conditions, thereby maintaining audio fidelity across different scenarios without causing distortion

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system performs preliminary encoding of multiple dynamic range profiles during the encoding phase rather than attempting to adapt in real-time at playback. This preliminary preparation of multiple versions allows the playback system to simply select the appropriate pre-encoded version based on device capabilities, avoiding the need for complex real-time processing that could introduce distortion

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If multiple DRC profiles are transmitted for every frame, then adaptability to different rendering modes is maximized, but bandwidth consumption increases significantly

Engineering Contradiction:

Improveadaptability to rendering modesVSAvoidbandwidth consumption

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The transmission is segmented such that only necessary DRC profile information is sent in each frame. Instead of transmitting complete DRC profiles for every frame, the system sends profile identifiers or differential updates only when the rendering mode actually changes, significantly reducing bandwidth consumption while maintaining adaptability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The DRC profile data structure is designed to serve multiple rendering modes simultaneously. A single set of encoded audio data with embedded DRC profiles can be adapted to different playback scenarios (headphones, speakers, noisy environments, quiet rooms) without requiring separate encodings for each mode, thereby reducing overall bandwidth requirements

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP4044180B1Decoding an encoded audio signal using DRC profiles

Publication Date: 2024.10.30 DOLBY INTERNATIONAL AB

Figure 1
Figure 2
Figure 3

AI summary

Decoding an encoded audio signal comprising frames of encoded audio data and metadata, the metadata including different dynamic range control, DRC, gains. Decoding according to a DRC gain profile corresponding to a desired output reference level. Determining a loudness related gain based on the indication of the loudness level of the audio signal and the desired output reference level. Applying the loudness related gain to obtain loudness adjusted audio data that has the desired output reference level.