Loudness Control Based On FPGA

The loudness control of audio is based on a series of processing like embedded digital audio, audio loudness measurements audio de-embedding and addition control adjustment to make sure audio loudness of consistency, which meets the requirements of loudness control standards. Loudness control plays a pivotal role in the process of the radio in radio and TV industry, so, more and more equipment vendors involved in recent years. With the rapid development of radio and television digital technology, high-definition video brings unprecedented visual experience. But when broadcast audio loudness difference problems seriously affect the user experience of hearing. The current audio equipment is expensive and processing complex has prevented the broadcast audio quality.With its relatively low price, easy programming, fast processing speed, the characteristics of flexible and parallel processing, field programmable gate array(FPGA) has great advantage of in the field of audio signal processing equipment, and it has become one of the most important option for the realization of audio signal processing.The purpose of this thesis is designed to achieve real-time detection and control of loudness system based on FPGA. While meeting the rapid processing requirements, the system has some advantage such as the good real-time, low resource consumption, widely controlling the audio frequency range and well control effects.Based on the digital audio signal as the research object, this thesis deeply studied the audio voLKFSme control method. The traditional audio compression limiting algorithm, the equalizer control algorithm, as well as the audio segmentation processing algorithm, on this basis, combining with the characteristics of FPGA, this thesis proposes a sectional loudness control algorithm. For different frequency audio perceptual human ear, and adopts the method of filtering section the input audio data segmentation processing control, so as to improve the effect of audio vo LKFSme control. Considering the particularity of SDI signal, the problem of embedding audio in the SDI signal has been studied. When audio data is embedded, you need to demultiple the embedded audio out of the blanking area, then measure and control audio loudness. After adjusting the loudness, we need to embed the the audio into the video stream in the blanking area. The whole design is based on the development board with the XC6SLX45T-3fgg484 as the core chip from Xilinx company implementation on FPGA.This experiment on the whole, in the form of hardware and external key coordination realize audio voLKFSme control, the hardware circuit to complete audio data speed processing, through the outer button can be set to the size of the loudness in the configuration and parameters, and dynamic range. Can according to the needs of the user through the outer button to configure the adjustment the loudness control size and dynamic range required to achieve the corresponding control and adjustment.System test results show that the audio loudness control system normal function, in SDI signal or HDMI signal can be configured through external key size and loudness expect the loudness of dynamic range and can implement the audio loudness of the signal measurement and control, the switching signal no loudness difference too much problems. Less system resource consumption, support the SDI signal and the signal of the HDMI inputs, good real-time, basic meet the demands of the current mainstream audio processing.