Audio Decoder Gain Metadata for Dynamic Range and Clipping Control

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Solution Overview

Problem

Conventional audio decoding technologies face challenges in dynamically controlling dynamic range and preventing clipping, leading to inefficiencies and additional computational complexity due to the lack of encoder-side control over clipping prevention mechanisms.

Innovation Solution

An audio encoder and decoder system that combines dynamic range compression and guided clipping prevention by including dynamic range control gain sequences and guided clipping prevention gain sequences in a metadata bitstream, allowing for encoder-side control and reducing the need for decoder-side peak limiters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If decoder-side peak limiters are used for clipping prevention, then clipping can be prevented, but computational complexity increases and control flexibility decreases

Engineering Contradiction:

Improveclipping preventionVSAvoiddecoder computational complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by computing clipping prevention gain sequences at the encoder side and embedding them in the bitstream before decoding. The decoder simply applies these pre-computed gains without performing complex peak limiting algorithms, thus preventing clipping while reducing decoder computational complexity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts the clipping prevention function from the decoder and relocates it to the encoder. The encoder computes and embeds the necessary gain sequences in the metadata, allowing the decoder to avoid implementing complex peak limiting mechanisms while still achieving clipping prevention.

Inventive Principle:

Principle #2Taking out (Extraction)

2Adaptability or versatility

If dynamic range control and clipping prevention are handled separately at the decoder, then each function can be implemented independently, but overall system complexity and processing overhead increase

Engineering Contradiction:

Improveindependent function controlVSAvoiddecoder processing overhead

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges dynamic range control and clipping prevention by embedding both types of gain sequences in the same metadata structure at the encoder. The decoder receives unified guidance information that simultaneously controls both dynamic range adjustment and clipping prevention, reducing processing overhead while maintaining independent controllability of each function.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11551703B2Concept for combined dynamic range compression and guided clipping prevention for audio devices

Publication Date: 2023.01.10 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

The invention provides a concept for combined dynamic range compression and guided clipping prevention for audio devices. An audio decoder for decoding an audio bitstream and a metadata bitstream related to the audio bitstream according to the concept includes an audio processing chain including a plurality of adjustment stages including a dynamic range control stage for adjusting a dynamic range of the audio output signal and a guided clipping prevention stage for preventing clipping of the audio output signal; and a metadata decoder configured to receive the metadata bitstream and to extract dynamic range control gain sequences and guided clipping prevention gain sequences from the metadata bitstream, at least a part of the dynamic range control gain sequences being supplied to the dynamic range control stage, and at least a part of the guided clipping prevention gain sequences being supplied to the guided clipping prevention stage.