Stereo Audio Decoding with Overlap Concatenation for Delay Matching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing embedded encoding/decoding technologies for sound signals with multiple channels and monaural signals result in larger algorithmic delay for stereo decoding compared to monaural decoding, complicating control in systems like multipoint control units for conference calls.
Innovation Solution
A sound signal decoding method that includes monaural decoding with frame overlap processing, additional decoding for overlap sections, and stereo decoding using a characteristic parameter to concatenate monaural and additional decoded signals, ensuring the algorithmic delay of stereo encoding/decoding does not exceed that of monaural encoding/decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a monaural encoding/decoding scheme with window overlap processing is used for embedded encoding/decoding, then the audio quality is improved, but the algorithmic delay of stereo decoding becomes larger than that of monaural decoding
Solution Approach 1:
The decoding process is segmented into three distinct parts: monaural decoding for the current frame, additional decoding for the overlap section using the next frame's data, and concatenation to form the complete decoded downmix signal. This segmentation allows precise control over when each decoding operation occurs, ensuring that stereo decoding completes at the same time as monaural decoding despite the window overlap processing.
Solution Approach 2:
The patent performs preliminary decoding of the overlap section using data from the next frame before the current frame's stereo decoding is complete. By preparing the additional decoded signal in advance and storing it, the system ensures that the concatenation operation can complete simultaneously with monaural decoding, eliminating the delay difference.
2Ease of operation
If stereo decoded sound signal is delayed by one frame with respect to monaural decoded sound signal, then control switching in multipoint control units becomes feasible, but the control complexity increases
Solution Approach 1:
The patent merges the monaural decoded sound signal and the additional decoded signal through concatenation to form a complete decoded downmix signal. This merging occurs at the optimal point in the processing pipeline, allowing the stereo decoded signal to be synchronized with the monaural decoded signal without requiring complex frame-delay control logic in multipoint control units.
Data Source
AI summary
The stereo decoding unit 220 performs steps S222-1 and S222-2 below (step S222). The stereo decoding unit 220 obtains a signal concatenating a sum signal (a signal configured by addition of sample values of corresponding samples) of the monaural decoded sound signal for the section Y and the additional decoded signal for the section Y and the additional decoded signal for the section X, as a decoded downmix signal for the section Y+X (step S222-1) instead of step S221-1 performed by the stereo decoding unit 220 of the first embodiment and obtains and outputs the decoded sound signals of the two channels from the decoded downmix signal obtained at step S222-1 by the upmix processing using the characteristic parameter obtained from the stereo code CS, using the decoded downmix signal obtained at step S222-1 instead of the decoded downmix signal obtained at step S221-1 (step S222-2).