当我使用ffmpeg转换m3u8为 时mp4，我收到一些警告，
ffmpeg -i xx.m3u8 -c copy demo.mp4
警告是
Non-monotonous DTS in output stream 0:1; previous: 3277744, current: 3276712; changing to 3277745. This may result in incorrect timestamps in the output file.
Non-monotonous DTS in output stream 0:1; previous: 3277745, current: 3277736; changing to 3277746. This may result in incorrect timestamps in the output file.
我该怎么做才能解决它？