H.324M protocol-based 3G video telephone audio and video synchronization device and method thereof

Abstract

The invention relates to an H.324M protocol-based 3G video telephone audio and video synchronization device and a method thereof. An adaptation layer AL2 layer of an H.324M protocol stack can be utilized to carry frame numbers, and a circuit switched domain on which the H.324M protocol stack is based can ensure the order of audio and video frame transmission to finish the frame matching of a transmitting end and a receiving end. Skew delay adjustment parameters of the H.324M protocol stack can be utilized to ensure the audio and video synchronization of the transmitting end. Video streams and audio streams are divided into a plurality of audio and video synchronization estimation units according to a time axis based on H.324M protocol automatic control video frame transmitting time points. The transmitting and receiving ends of the video frames and the audio frames are matched to accurately measure the delay of the video frames and the audio frames in the 3G telephone. A formula for calculating the synchronization deviation degree of audio and video is put forward and the method for measuring the audio and video synchronization under a frame loss condition is given, namely, the synchronization deviation degree of the audio and video and channel signal intensity are associated and displayed in a comparison way in a form of oscillogram, and an average absolute deviation formula is utilized to associate the objective estimation on the audio and video synchronization with the subjective estimation on the audio and video synchronization.

Description

technical field [0001] The invention relates to an audio and video synchronous testing device and method for a video phone based on the H.324M protocol used in a 3G mobile wireless network drive testing system. Background technique [0002] The mobile wireless network drive test system is a system for planning and optimizing the mobile wireless network by using tools such as test software, test mobile phones, frequency scanners, electronic maps, GPS and test vehicles. It mainly meets the needs of network cell site selection, daily network optimization, and radio frequency quality assessment. [0003] Video telephony is a main function of 3G wireless network. The audio and video quality evaluation of video telephony is an important test index for drive test optimization. Audio and video quality assessment is mainly divided into three categories: 1. Audio quality assessment; 2. Video quality assessment; 3. Audio and video synchronization assessment. At present, the internati...

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Problems solved by technology

[0004] The traditional voice and video synchronization control strategy usually adds additional time stamp data to each audio frame and video frame, and relies on time stamps for synchronization, but the transmission bandwidth in the 3G network is very limited, especially for TD-SCDMA In both 3G networks and WCDMA, video telephony is implemented based on 64K circuit-switched physical channels, which have extremely strict requirements on the size of transmitted data packets. Time stamp information based on synchronization will affect the inherent video quality and audio quality, and the H.223 multiplexing sub-protocol included in the H.324M protocol does not provide a frame format for encoding time stamps

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