Audio Metadata Loudness Control for Real-Time Playback Adaptation
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Solution Overview
Problem
Existing audio playback systems struggle with real-time loudness management and dynamic range control, especially when the entire audio program or segment cannot be analyzed prior to encoding, leading to compromised listening experiences and altered creative intent.
Innovation Solution
A metadata-based approach for dynamic loudness adjustment and range compression, using metadata to apply real-time processing parameters based on decoder settings and playback conditions, allowing for dynamic loudness management and DRC without altering the original audio content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the entire audio program is analyzed prior to encoding to determine loudness and DRC parameters, then loudness management and dynamic range control accuracy is improved, but real-time encoding capability deteriorates
Solution Approach 1:
The patent applies preliminary action by calculating and storing loudness and dynamic range control parameters during the encoding phase, rather than requiring post-encoding analysis. The encoder processes the audio program in real-time, computes metadata parameters (such as loudness levels and DRC settings) as the audio is being encoded, and embeds this metadata into the bitstream. This allows playback devices to apply accurate loudness management and dynamic range control without requiring prior analysis of the entire program, thus resolving the contradiction between measurement accuracy and real-time encoding capability.
2Reliability
If loudness processing or levelling is applied to optimize audio for a single playback environment, then loudness compliance is improved, but adaptability to different playback devices deteriorates
Solution Approach 1:
The patent applies parameter changes by encoding multiple sets of metadata parameters corresponding to different playback environments and device types. Instead of applying fixed loudness processing optimized for a single environment, the encoder generates alternative metadata parameter sets (such as different loudness metadata, DRC parameters, and playback condition information) that can be selectively applied depending on the actual playback device characteristics. This allows the system to maintain loudness compliance across various playback environments while adapting to specific device capabilities, thus resolving the contradiction between reliability and adaptability.
3Stability of the object's composition
If processed audio is delivered optimized for a single playback environment, then playback consistency is improved, but preservation of original audio quality deteriorates
Solution Approach 1:
The patent applies the taking out principle by separating the loudness management and dynamic range control processing from the original audio signal. Instead of permanently modifying the audio data through processing or levelling, the system extracts the essential loudness and DRC parameters into metadata that travels alongside the original, unprocessed audio in the bitstream. The actual audio data remains unchanged and preserved in its original quality, while the extracted metadata parameters enable playback devices to apply appropriate loudness management and dynamic range control based on their specific playback conditions, thus resolving the contradiction between playback consistency and preservation of original audio quality.
Data Source
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AI summary
Described herein is a method of metadata-based dynamic processing of audio data for playback, the method including: receiving, by a decoder, a bitstream including audio data and metadata for dynamic loudness adjustment; decoding, by the decoder, the audio data and the metadata to obtain decoded audio data and the metadata; determining, by the decoder, from the metadata, one or more processing parameters for dynamic loudness adjustment based on a playback condition; applying the determined one or more processing parameters to the decoded audio data to obtain processed audio data; and outputting the processed audio data for playback. Described is further a method of encoding audio data and metadata for dynamic loudness adjustment into a bitstream. Moreover, described are a respective decoder and encoder, a respective system and computer program products.