应用科学学报 ›› 2018, Vol. 36 ›› Issue (3): 504-514.doi: 10.3969/j.issn.0255-8297.2018.03.010

• 信号与信息处理 • 上一篇    下一篇

面向嵌入式系统的音视频解码与同步播放实现

张森永, 高树立, 陈为刚   

  1. 天津大学 电子信息工程学院, 天津 300072
  • 收稿日期:2016-10-26 修回日期:2017-01-04 出版日期:2018-05-31 发布日期:2018-05-31
  • 通信作者: 陈为刚,副教授,研究方向:无线通信理论与系统、信息理论与编码技术,E-mail:chenwg@tju.edu.cn E-mail:chenwg@tju.edu.cn
  • 基金资助:

    青岛海洋科学与技术国家实验室项目基金资助

Implementation of Audio and Video Decoding and Synchronous Playback Based on Embedded Systems

ZHANG Sen-yong, GAO Shu-li, CHEN Wei-gang   

  1. School of Electronic Information Engineering, Tianjin University, Tianjin 300072, China
  • Received:2016-10-26 Revised:2017-01-04 Online:2018-05-31 Published:2018-05-31

摘要:

基于ARM嵌入式系统设计并实现了MPEG-2 TS流的音视频解码和同步播放系统.在该系统中,由于ARM处理器内嵌了硬件视频解码器,为充分利用该资源,采用硬件MFC(multi-format codec)解码器对视频数据进行解码,同时采用开源的Mad (libmad)库对音频数据进行解码.进一步利用V4L2(Video for Linux 2)驱动接口和ALSA(advancedLinux sound architecture)库实现视频和音频的播放.由于视频帧播放周期和硬件处理时延不一致,系统对音视频数据操作存在时间差,从而造成音视频播放不同步.于是采用将视频播放同步到音频播放流的方法实现音视频的播放同步.测试结果表明,设计的音视频解码和同步播放系统可以实现对音视频数据进行解码与同步播放.

关键词: 音视频解码, 音视频同步, 多线程, 嵌入式系统

Abstract:

An MPEG-2 TS stream decoding and synchronous playback system is designed and implemented based on ARM embedded system. In order to make full use of the resource of video codec embed in ARM processor, a hardware MFC codec is adopted to decode video data, and the open-source Mad- library (libmad) is used to decode audio data. Furthermore, V4L2 driver interface and ALSA library are adopted to play video and audio frame. Due to the delay of hardware decoding from video frame period, there exists a time difference between audio and video playbacks, causing audio and video unsynchronized. In the designed system, a method that synchronizes the video playback to the audio playback is used to achieve synchronization of audio and video playback. Test results show that the designed system can realize audio and video data decoding and synchronous playback.

Key words: audio and video decoding, audio and video synchronization, embedded system, multithreading

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