Audio Transcoder Using Encoder Side Information
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Solution Overview
Problem
Existing transcoding methods for digital audio, such as the decode-and-encode approach, incur high computational complexity and result in degraded audio quality due to the need for full decoding and re-encoding of audio signals, especially when changing bit-rates for different application scenarios.
Innovation Solution
The proposed transcoding technique encodes side information into the compressed bitstream to skip intensive encoding processes, allowing for partial decoding and re-encoding, thereby avoiding full reconstruction of the audio signal and maintaining better quality by using preserved information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If full decoding and re-encoding is performed to change bit-rate, then audio quality can be maintained, but computational complexity increases significantly
Solution Approach 1:
The encoder generates and embeds side information about the original audio signal during the initial encoding process. This preliminary action stores essential signal characteristics that can be reused during transcoding, avoiding the need for full decoding and re-encoding while maintaining audio quality.
Solution Approach 2:
Side information acts as an intermediary between the original audio signal and the transcoding process. Instead of directly decoding the compressed bitstream to time-domain samples and re-encoding, the transcoder uses the embedded side information to guide the encoding process at the target bit-rate, reducing computational complexity.
2Manufacturing precision
If full decoding and re-encoding is performed to change bit-rate, then audio quality can be maintained, but processing time increases
Solution Approach 1:
Essential signal characteristics are extracted and embedded as side information during the initial encoding process. This preliminary extraction of useful information enables the transcoder to skip time-consuming full decoding operations while still maintaining audio quality in the transcoded output.
Solution Approach 2:
Instead of performing the complete decoding and re-encoding process, the transcoder performs only partial encoding operations using the embedded side information. This partial action approach maintains audio quality while significantly reducing processing time by omitting unnecessary full decoding steps.
3Device complexity
If side information is encoded into the compressed bitstream, then computational complexity during transcoding is reduced, but the initial bitstream size increases
Solution Approach 1:
The encoder extracts and embeds only the essential side information needed for efficient transcoding, rather than storing the complete original audio signal. This selective extraction minimizes the increase in bitstream size while still enabling computational complexity reduction during transcoding operations.
Solution Approach 2:
The side information contains transformed domain parameters and signal characteristics that are more compact representations of the original audio signal. By encoding these parameters instead of the full signal, the bitstream size increase is minimized while still enabling efficient transcoding with reduced computational complexity.
Data Source
AI summary
An audio encoder encodes side information into a compressed audio bitstream containing encoding parameters used by the encoder for one or more encoding techniques, such as a noise-mask-ratio curve used for rate control. A transcoder uses the encoder generated side information to transcode the audio from the original compressed bitstream having an initial bit-rate into a second bitstream having a new bit-rate. Because the side information is derived from the original audio, the transcoder is able to better maintain audio quality of the transcoding. The side information also allows the transcoder to re-encode from an intermediate decoding/encoding stage for faster and lower complexity transcoding.