Audio Encoder Parameters for Low-Bitrate Error Concealment
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Solution Overview
Problem
Existing error concealment mechanisms in VoIP systems are inadequate for reconstructing defective audio frames, leading to poor quality due to packet loss and corruption, as they rely on low bitrate redundant copies that compromise audio quality.
Innovation Solution
An encoder embeds selected error concealment helper parameters in the bitstream to enhance decoder-side concealment, allowing for the reconstruction of defective frames using information from preceding or following frames, while maintaining a low bitrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If low bitrate redundant copies are used for error concealment, then bandwidth efficiency is improved, but audio quality deteriorates
Solution Approach 1:
The patent extracts only the essential parameters needed for error concealment (such as spectral envelope parameters, pitch information, and energy levels) from the original audio frames and transmits these separately. This allows the decoder to reconstruct concealed frames with high quality using only these extracted parameters, avoiding the need to transmit full low-bitrate redundant copies while maintaining both bandwidth efficiency and audio quality.
2Manufacturing precision
If full error concealment information is transmitted, then concealment quality is improved, but bitrate increases
Solution Approach 1:
Instead of transmitting complete redundant frame data, the patent extracts and transmits only the critical parameters necessary for effective error concealment. These include spectral envelope parameters (LP coefficients or LSF), pitch period, pitch gain, and frame energy. This selective extraction achieves high concealment quality while keeping the additional bitrate requirement minimal compared to transmitting full frame data.
Solution Approach 2:
The patent segments the error concealment information into separate parameter components (spectral parameters, temporal parameters, energy information) that can be transmitted independently. This segmentation allows the decoder to reconstruct concealed frames using only the necessary parameter segments, reducing the total amount of data that needs to be transmitted while maintaining concealment quality.
3Reliability
If redundant copies are transmitted for every frame, then error protection is improved, but device complexity increases
Solution Approach 1:
The patent performs preliminary extraction of error concealment parameters during the normal encoding process, before any error occurs. These parameters are extracted and stored alongside the main encoded data, ready for immediate use if frame loss occurs. This preliminary preparation simplifies the encoding complexity by integrating parameter extraction into the existing encoding pipeline rather than adding separate redundant encoding processes.
Solution Approach 2:
The patent enables the decoder to perform self-service error concealment by providing it with the necessary parameters to reconstruct lost frames independently. The decoder uses the transmitted parameters (spectral parameters, pitch information, energy levels) to generate concealed frames without requiring complex inter-frame prediction or external assistance, thereby reducing overall system complexity while maintaining reliable error protection.
Data Source
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AI summary
The present invention concerns an encoder for coding speech-like content and/or general audio content, wherein the encoder is configured to embed, at least in some frames, parameters in a bitstream, which parameters enhance a concealment in case an original frame is lost, corrupted or delayed, and a decoder for decoding speech-like content and/or general audio content, wherein the decoder is configured to use parameters which are sent later in time to enhance a concealment in case an original frame is lost, corrupted or delayed, as well as a method for encoding and a method for decoding.