Audio Pulse Position Decoding Using State Number Encoding
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Solution Overview
Problem
Current ACELP encoding methods require a high number of bits to represent pulse positions, leading to increased transmission and storage requirements for audio signals, and lack efficiency in encoding and decoding pulse information.
Innovation Solution
The proposed solution involves an apparatus and method for encoding and decoding pulse positions using a state number that efficiently represents pulse positions and signs across multiple tracks, allowing for reduced bit usage by utilizing a pre-determined number of bits and optimizing pulse encoding strategies, enabling direct selection of the appropriate number of pulses for a given bit rate without needing to try different amounts until the desired bit-rate is achieved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If traditional ACELP encoding methods are used to represent pulse positions, then encoding quality is maintained, but the number of bits required for transmission and storage increases
Solution Approach 1:
The invention segments the pulse encoding process into two distinct phases: a first encoding pass that processes pulses up to a first threshold position, and a second encoding pass that processes pulses beyond the threshold. This segmentation allows different encoding strategies to be applied to different pulse groups, reducing the total number of bits required while maintaining encoding quality
Solution Approach 2:
The invention introduces dynamic threshold adjustment where the first threshold position is not fixed but can be adapted based on the specific audio signal characteristics and pulse distribution. This dynamic approach allows the encoding system to optimize bit usage for each frame independently, improving overall efficiency without increasing complexity
2Measurement precision
If more bits are used to represent pulse positions, then encoding precision is improved, but transmission and storage requirements increase
Solution Approach 1:
The invention applies different encoding precision to different pulse positions. Pulses within the first threshold position range are encoded with one level of precision, while pulses beyond the threshold are encoded with a different precision level. This local quality approach ensures sufficient precision for critical pulses while using fewer bits for less critical positions, reducing overall data volume
Solution Approach 2:
The invention changes the encoding parameter (number of bits allocated) based on the pulse position relative to the threshold. By dynamically adjusting the parameter representation based on position, the system achieves variable precision encoding that optimizes the balance between measurement precision and data quantity
3Productivity
If variable bit allocation is used for different pulse configurations, then encoding efficiency is improved, but device complexity increases
Solution Approach 1:
The invention performs preliminary classification of pulses during encoding by separating them into two groups based on the threshold position. This preliminary action during encoding simplifies the decoding process, as the decoder can follow a corresponding predetermined sequence without requiring complex analysis, thus improving encoding speed while keeping decoder complexity manageable
Data Source
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AI summary
An apparatus for decoding an encoded audio signal, wherein one or more tracks are associated with the encoded audio signal, each one of the tracks having a plurality of track positions and a plurality of pulses is provided. The apparatus comprises a pulse information decoder (110) and a signal decoder (120). The pulse information decoder (110) is adapted to decode a plurality of pulse positions, wherein each one of the pulse positions indicates one of the track positions of one of the tracks to indicate a position of one of the pulses of the track, and wherein the pulse information decoder is configured to decode the plurality of pulse positions by using a track positions number indicating a total number of the track positions of at least one of the tracks, a total pulses number indicating a total number of the pulses of at least one of the tracks, and one state number. The signal decoder (120) is adapted to decode the encoded audio signal by generating a synthesized audio signal using the plurality of pulse positions and a plurality of predictive filter coefficients being associated with the encoded audio signal.