使用opencv读取本地视频文件，并在播放窗口添加进度条-Read the local video files using opencv, and add the progress bar in the player window

1.摄像头通过V4L2采集yuyv格式图像数据 2.yuyv转yuv420p格式 3.yuv420p通过x264编码压缩为h264码流 4.将h264码流通过tcp传输到显示端 5.显示端接收h264码流，并保存为本地文件，程序运行结束后可通过VLC播放器直接打开xxxx.h264文件进行播放(1. Camera collects image data in Yuyv format by V4L2. Yuyv converts to Yuv420p format. Yuv420p is comp