Parametric Audio DRC Restoration for Seamless Bitrate Switching
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Solution Overview
Problem
Existing adaptive distribution formats for audiovisual media struggle with maintaining backward compatibility and often result in dynamic range inconsistencies during bitrate switching, especially in legacy equipment.
Innovation Solution
A coding format that includes pre-processing and post-processing dynamic range control (DRC) parameters to ensure consistent dialogue levels by allowing for dynamic range restoration and adjustment, enabling seamless bitrate transitions without sharp changes in the audio signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If adaptive bitrate switching is implemented in legacy equipment, then network resource utilization is improved, but dynamic range inconsistencies occur during bitrate transitions
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing compensation values for dynamic range control parameters before bitrate switching occurs. The system prepares adjustment data in advance that will be applied during transitions, ensuring that dynamic range consistency is maintained without actual dynamic changes during the switching event itself.
Solution Approach 2:
The patent implements parameter changes by modifying the dynamic range control parameters (such as dialogue level compensation values) based on the target bitrate. The system adjusts these parameters proactively before the bitrate switch, allowing legacy equipment to maintain consistent dynamic range behavior across different bitrate conditions without requiring complex real-time processing.
2Manufacturing precision
If DRC parameters are dynamically adjusted during bitrate switching, then audio quality is improved, but computational complexity increases
Solution Approach 1:
The patent reduces computational complexity during runtime by performing all necessary DRC parameter calculations in advance. Compensation values for different bitrate scenarios are pre-computed and stored, eliminating the need for complex real-time calculations when bitrate switching occurs. This allows legacy equipment with limited processing capabilities to maintain high audio quality without increased computational burden during operation.
Solution Approach 2:
The patent uses copying by creating and storing pre-calculated DRC parameter sets for different bitrate conditions. Instead of performing complex calculations during bitrate transitions, the system copies and applies the appropriate pre-computed parameter set that matches the target bitrate, significantly reducing real-time computational requirements while maintaining audio quality.
3Adaptability or versatility
If legacy equipment supports adaptive bitrate formats, then backward compatibility is improved, but dynamic range control precision deteriorates
Solution Approach 1:
The patent maintains dynamic range control precision in legacy equipment by introducing and adjusting specific parameters (compensation values for dialogue level) that are tailored for adaptive bitrate operation. These parameter adjustments allow legacy decoders to achieve precision comparable to dedicated equipment by modifying how they interpret and apply DRC parameters during bitrate transitions.
Solution Approach 2:
The patent ensures precise dynamic range control in legacy equipment by pre-calculating compensation parameters that account for the specific limitations and characteristics of legacy decoders. This preliminary preparation allows legacy equipment to maintain high precision without requiring complex real-time adjustments or upgrades to the decoder architecture.
Data Source
AI summary
On the basis of a bitstream (P), an n-channel audio signal (X) is reconstructed by deriving an m-channel core signal (Y) and multichannel coding parameters (a) from the bitstream, where 1≤m<n. Also derived from the bitstream are pre-processing dynamic range control, DRC, parameters (DRC2) quantifying an encoder-side dynamic range limiting of the core signal. The n-channel audio signal is obtained by parametric synthesis in accordance with the multichannel coding parameters and while cancelling any encoder-side dynamic range limiting based on the pre-processing DRC parameters. In particular embodiments, the reconstruction further includes use of compensated post-processing DRC parameters quantifying a potential decoder-side dynamic range compression. Cancellation of an encoder-side range limitation and range compression are preferably performed by different decoder-side components. Cancellation and compression may be coordinated by a DRC pre-processor.