Video out of sync when imported

Windows 7
Shotcut version 21.12.24

This is a complete mystery to me. So I add the clip to the playlist (I’ve tried drag and drop as well as open file) and play it BUT the start of the video as it appears in shotcut is few seconds ahead and the sound is from the middle of the video (I played it in VLC to verify this). The video and the audio are completely out of sync. I’ve also been hearing some stuttering and cut-outs with the audio in playback. And I’ve tried restarting shotcut multiple times and re-adding the video… with the same result every time. I haven’t had this issue before and there isn’t anything special about this video file, it’s just a 720p mp4 (5 mins, 190mb). (note: I also played the video in windows media player and it is also out of sync exactly the same as in shotcut).
Log is attached.
Thanks in advance for any advice.

log.txt (114.4 KB)

I don’t understand how it is a bug or problem?

You are basically saying that it is out of sync everywhere you try it, so it doesn’t seem a shotcut problem, it seems that the video has the problem itself.

But you can try the sync slider in the video properties to match the audio and video. Or covert it to edit friendly from the same tab.

Look like there is some problem with the video file.

1 Like

I converted it to edit friendly and it was fine! Thanks.
Any idea why this happens? It played fine in VLC

It is usually because the video use a variable bitrate rate (VBR) is makes it hard for a video editor to keep things in sync, so converting it to a format with a fixed bitrate helps alot.

Sorry but not going to try to change A/V sync based on one problematic input. A/V sync is incredibly difficult to maintain and keep working with the same amount of coverage after any kind of change. You need to try using Properties > Convert if it is not working well. And I think if that did not help, perhaps manually sync using displacement on the timeline with detached audio or Properties > Audio > Sync.

the video use a variable bitrate rate (VBR)

No, that is not a problem, but variable frame rate is.


This happens because videos are of two types, interlaced and progressive, progressive videos are edit friendly, so they usually don’t have problems, but interlaced are vice versa. Variable frame rate also causes this problem as Dan said.