Spatial Audio Ratio Encoding With Lattice Index Compression
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Solution Overview
Problem
Existing spatial audio encoding methods face inefficiencies in encoding and decoding ISM ratio parameters, particularly in immersive audio codecs like IVAS, due to the need for memory-intensive lattice index storage and insufficient data for entropy encoding, which affects compression efficiency and decoding accuracy.
Innovation Solution
An indexing method for lattice Zn vectors is employed that does not require storing index offsets, using pyramidal truncation and entropy encoding to efficiently encode ISM ratios, and a method for generating and decoding integer values representing these ratios is developed, allowing for efficient encoding and decoding of spatial metadata.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lattice index storage is used for encoding ISM ratios, then decoding accuracy is maintained, but memory requirements increase significantly
Solution Approach 1:
The patent extracts only the essential information needed for decoding by using a simplified indexing method that references pre-defined lattice vectors stored in the decoder, rather than transmitting full lattice index data. This removes unnecessary data from the bitstream while maintaining decoding accuracy.
Solution Approach 2:
Instead of storing and transmitting comprehensive lattice index information in the encoder memory, the patent inverts the approach by having the decoder store the lattice vectors and use received index values to retrieve the correct vectors. This shifts the memory burden from encoder to decoder.
2Productivity
If traditional entropy encoding is applied to ISM ratios, then compression efficiency is improved, but insufficient data availability limits its effectiveness
Solution Approach 1:
The patent merges multiple ISM ratio parameters into a unified lattice vector representation, combining several pieces of spatial information into a single structured format. This consolidation creates sufficient data for effective entropy encoding while preserving all necessary information.
Solution Approach 2:
The patent transforms ISM ratio parameters from their original form into lattice vector indices, changing the parameter representation to enable more efficient compression. This parameter transformation allows entropy encoding to work effectively with the new indexed format.
3Measurement precision
If full lattice index information is transmitted, then decoding accuracy is ensured, but bit rate increases
Solution Approach 1:
The patent uses compact index values that copy only the essential identification information needed to retrieve the full lattice vectors at the decoder side. These index copies are much smaller than transmitting the complete vector data while ensuring accurate reconstruction.
Solution Approach 2:
The patent transitions from transmitting high-dimensional lattice vector data to transmitting low-dimensional index values that point to the vectors. This dimensional reduction dramatically decreases bit rate while maintaining the ability to accurately reconstruct the original spatial information.
Data Source
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AI summary
An apparatus, for encoding an audio object parameter; the apparatus comprising means for: obtaining a ratio parameter associated with a respective audio object within an audio environment, the audio environment comprising at least two audio objects and the ratio parameters configured to identify a distribution of the respective object within the object part of the total audio environment; quantizing the ratio parameters with respect to the audio objects using a first number of bits; generating a vector from a selection of the quantized ratio parameters; and generating an integer value based on an indexing from the vector, wherein the generated integer value represents the ratio parameters for the at least two audio objects.