read recordinfo.txt,transcode ,and save recordinfo_out.txt
in previous version,all the audio an video are merged to one ts,
in this version,there are maybe serveral ts,if the video file or audio file is not continuous
1.using the video duration parsed from video file
2.make compatiable with the recording file with the start time not being zero
3.merge with blank jpg for the last segment audio without video
4.adjust video codec param ,using cfr, 20fps,gop 100
