Synchronized Swept-Sine: Theory, Application, and Implementation - October 2015
Effect of Microphone Number and Positioning on the Average of Frequency Responses in Cinema Calibration - October 2015
The Measurement and Calibration of Sound Reproducing Systems - July 2015
Quality Improvement of Very Low Bit Rate HE-AAC Using Linear Prediction Module
This paper proposes a new method of improving the quality of High Efficiency Advanced Audio Coding (HE-AAC) at very low bitrate under 16kbps. Low bitrate HE-AAC often produces obvious spectral holes inducing musical noise in low energy frequency bands, due to limited number of available bits. In the proposed system, a Linear Prediction (LP) module is combined with HE-AAC as a pre-processor to reduce the spectral holes. In its implementation, masking threshold of psychoacoustic model is normalized using the LP spectral envelope in prior to quantization of the LP residual. Also, in order to reduce the pre-echo, a block switching module is modified. Experimental results show that, at very low bitrate modes, the linear prediction module effectively reduces spectral holes, which results in reduction of musical noises of the conventional HE-AAC.
Click to purchase paper or login as an AES member. If your company or school subscribes to the E-Library then switch to the institutional version. If you are not an AES member and would like to subscribe to the E-Library then Join the AES!
This paper costs $20 for non-members, $5 for AES members and is free for E-Library subscribers.