Implementation Of A/V Receiving And Synchronous Playback With Embedded Systems

With the rapid development of information technology,embedded audio and video playback terminal is widely used in people's daily life.There are different decoding delays while using software and hardware decoder in audio and video playback system.Therefore,audio and video playback is not synchronized.An audio and video capture-compression system is implemented based on computer and capture card.Furthermore,an audio and video synchronous playback system is designed based on ARM embedded platform.And an effective synchronous playback method is implemented on playback system.First,the audio and video capture-compression system is implemented based on the MPEG-2 standard system.The designed capture-compression system is divided into several sub-modules,which are acquisition module,compression module and multiplexing module.Acquisition module samples the input signal of audio and video using ALSA and V4L2 interface.Compression module and multiplexing module is designed to compress audio and video data into continuous data stream and multiplex them into a single transport stream with FFmpeg library.Then,the audio and video synchronous playback system is designed and implemented on the ARM embedded platform.The synchronous playback system is composed of demultiplexing module,decoding module and synchronous playback module.MFC decoder is used for video decoding and mad library is adopted to decode audio data in decoding module.Moreover,an audio and video synchronization method is implemented based on timestamp synchronization.The designed method adjusts video play time to achieve synchronization of audio and video.The test results show that the audio and video synchronous playback system can effectively realize the synchronous playback of audio and video.In conclusion,the audio and video capture-compression system and synchronous playback system is designed and implemented in this paper.And the performance of designed synchronization method is tested.This work provides a reference for the design of audio and video synchronization method on the embedded platform.