Digital audio/video synchronization method, device and system

Abstract

The invention discloses a method and system for synchronizing digital audio and video. The system is composed of an audio and video acquisition device and a host controller. The method includes the following steps: the host controller generates periodic signals, and the generated The periodic signal is sent to the audio and video acquisition device; the audio and video acquisition device calibrates the audio clock signal generated by itself according to the received periodic signal, and samples the audio signal according to the calibrated audio clock signal to obtain audio data; at the same time, The audio and video acquisition device calibrates the video clock signal generated by itself according to the received periodic signal, and samples the video signal according to the calibrated video clock signal to obtain video data; the audio and video acquisition device calibrates the audio data and video data sent to the host controller, and the host controller decodes the received audio data and video data according to the periodic signal. The invention also discloses an audio and video collection device.

Description

technical field [0001] The invention relates to the technical field of digital video and audio signal processing, in particular to a method, device and system for synchronizing digital audio and video. Background technique [0002] During the acquisition, transmission, codec and other processing of digital video signals and digital audio signals, maintaining time synchronization between the two is a very important issue. [0003] in such as figure 1 In the shown conventional Universal Serial Bus (USB) transmission system, the audio and video capture device 110 is connected to the USB host controller 120 through the USB interface. The audio and video collection device 110 includes an audio clock generation unit 111 , an audio sampling unit 112 , a video clock generation unit 113 and a video sampling unit 114 . The audio clock generation unit 111 sends the audio clock signal produced to the audio sampling unit 112, and the audio sampling unit 112 performs audio sampling acco...

AI Technical Summary

Problems solved by technology

[0005] Even if a certain technical means is adopted to keep the video clock and the audio clock synchronized, for example, the same clock source is used to generate the video clock signal and the audio clock signal, it is still difficult to maintain synchronization between the video signal and the audio signal received by the USB host controller 120 sex

The reason is that after the USB host controller 120 receives the video signal and the audio signal, it decodes the video signal and the audio signal according to its own host clock, because there is a gap between the host clock signal and the video clock signal or audio clock signal There is no time synchronization, so there are random errors between the host clock signal and the video clock signal or audio clock signal

However, the acquisition frequency of the video signal is very different from the acquisition frequency of the audio signal, which makes the degree of influence of the random error on the decoded video signal or audio signal inconsistent, and this inconsistency will continue to accumulate over time , making the time synchronization between the video signal and the audio signal worse

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