Judging from your description, it is estimated that there are several reasons. Analyze and solve by yourself:

1. The second recording mode you set is incorrect (or the video recorder is out of order). The original document is wrong, and this cannot be solved.

2. Is the video captured by a capture card? Can be re-collected, with audio and video or PR.

3, the problem of playing software, it may be that the two video codes are not the same, resulting in QQ audio and video can not be decoded and played normally, changed to the latest version of the ultimate decoding.

4, computer system problems, this probability is extremely small.

5.RPWT, this, this is all I can think of.