Audio Object Encoding with Decoder Feedback for Cleaner Down-Mix Control
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Solution Overview
Problem
Existing audio object encoding and decoding systems suffer from suboptimal quality and cross-interference issues, limiting independent manipulation and flexibility, especially in down-mixing processes that are not completely reversible, leading to noticeable quality degradation.
Innovation Solution
An encoder that receives audio objects, encodes them into a number of audio signals with parametric data, and modifies these signals based on remote control data to improve user control and reduce cross-interference, allowing for high-quality, independent manipulation of audio objects by adjusting volume and frequency characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If audio objects are down-mixed into a limited set of channels with parametric data, then the system achieves backwards compatibility and reduced channel requirements, but the reproduction quality becomes suboptimal and cross-interference occurs between audio objects
Solution Approach 1:
The audio signal is segmented into multiple independent audio objects, each with its own parametric data including spatial position, volume, and frequency characteristics. This segmentation allows the decoder to independently manipulate each object while maintaining overall compatibility with legacy systems through down-mixing to standard channel configurations.
Solution Approach 2:
The system changes the representation parameters from traditional channel-based mixing to object-based parametric encoding. Each audio object is described by parameters such as spatial position, volume level, and frequency characteristics, allowing flexible manipulation and independent control without cross-interference, while still being renderable to standard channel formats for backwards compatibility.
2Adaptability or versatility
If the down-mix process is used to reduce the number of channels, then the system can be reproduced by legacy decoders, but the process is not completely reversible leading to quality degradation
Solution Approach 1:
The system performs preliminary encoding of audio objects with complete parametric data before transmission. The encoder stores the full object-based representation with all spatial and spectral parameters, allowing the decoder to reconstruct high-quality audio objects even when rendering to limited channel configurations. This preliminary preservation of complete information prevents irreversible quality loss.
3Ease of operation
If multiple audio objects are encoded independently, then user interaction and independent manipulation is possible, but cross-interference occurs affecting the independence of audio objects
Solution Approach 1:
The system incorporates feedback mechanisms where the encoder receives information about desired manipulations and adjusts the parametric data accordingly. When users interact with audio objects at the decoder, the system provides feedback to maintain object independence by adjusting parameters to prevent cross-interference, ensuring that manipulations of one object do not adversely affect others.
Data Source
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AI summary
An audio system comprises an encoder (209) which encodes audio objects in an encoding unit (403) that generates a down-mix audio signal and parametric data representing the plurality of audio objects. The down-mix audio signal and parametric data is transmitted to a decoder (215) which comprises a decoding unit (301) which generates approximate replicas of the audio objects and a rendering unit (303) which generates an output signal from the audio objects. The decoder (215) furthermore contains a processor (501) for generating encoding modification data which is sent to the encoder (209). The encoder (209) then modifies the encoding of the audio objects, and in particular modifies the parametric data, in response to the encoding modification data. The approach allows manipulation of the audio objects to be controlled by the decoder (215) but performed fully or partly by the encoder (209). Thus, the manipulation may be performed on the actual independent audio objects rather than on approximate replicas thereby providing improved performance.