Audio Decoder Gain Sequencing for Dynamic Range and Clipping Control
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Solution Overview
Problem
Current audio decoding technologies face challenges in effectively managing dynamic range compression and preventing clipping, particularly due to the lack of encoder-side control over clipping prevention, leading to increased computational complexity and additional delays at the decoder side.
Innovation Solution
The implementation of an audio decoder with a combined dynamic range compression and guided clipping prevention system, where dynamic range control gain sequences and guided clipping prevention gain sequences are transmitted in a metadata bitstream, allowing for encoder-side control and separate modification of gains based on decoder configuration and playback scenarios, thereby reducing the need for peak limiters and associated delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dynamic range compression and clipping prevention are performed separately at the decoder side, then audio quality is maintained, but computational complexity and processing delays increase
Solution Approach 1:
The patent combines dynamic range compression and clipping prevention into a single integrated processing stage at the decoder. The guided clipping prevention gain sequence is generated based on the dynamic range compressed signal, allowing both functions to be performed simultaneously rather than as separate sequential operations, thereby reducing computational complexity while maintaining audio quality
Solution Approach 2:
The encoder pre-calculates and transmits the guided clipping prevention gain sequence in the metadata bitstream. This preliminary action allows the decoder to directly apply the pre-computed gains without performing complex real-time clipping detection and prevention calculations, significantly reducing decoder computational load while preserving audio fidelity
2Reliability
If peak limiters are used for clipping prevention at the decoder, then clipping is prevented, but additional processing delays are introduced
Solution Approach 1:
The clipping prevention gains are pre-calculated at the encoder side and transmitted to the decoder via the metadata bitstream. The decoder simply applies these pre-determined gains without performing real-time peak detection and limiting operations, thereby eliminating the processing delays associated with traditional peak limiter algorithms while maintaining effective clipping prevention
Solution Approach 2:
The guided clipping prevention gain sequence acts as an intermediary that carries the clipping prevention information from the encoder to the decoder. Instead of the decoder implementing complex real-time limiting logic, it uses the pre-computed gain sequence as a mediator to achieve clipping prevention with minimal processing delay
3Adaptability or versatility
If encoder-side control over clipping prevention is implemented, then flexibility in gain modification is improved, but metadata bitstream complexity increases
Solution Approach 1:
The patent segments the audio processing control into two independent components: dynamic range compression parameters and guided clipping prevention parameters. Each can be separately configured, transmitted, and modified in the metadata bitstream, providing flexibility in gain modification while keeping the metadata structure organized and manageable through clear separation of concerns
Data Source
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.