AVIDemux Help: How do you fix a stream copied video that goes out of sync?

[Guernsey]

I was recommended AVIDemux after I realized that Virtualdub2 was not going to give me the results I wanted. I wanted to perform a stream copy of a videos that I wanted to upscale but after viewing the video that created clips from, I saw that one of my videos is out of sync. Audio is ahead of the video at certain points and I wonder if I did something wrong to make that happen? I just wanted to make a direct stream copy (or stream copy) of a video but it seems like the audio does not match the video that I wanted to stream copy. Can somebody please help me find a solution? I think I just need to find a better source to create clips from.

[ProWo]

What exactly do you want to do?

[Guernsey]

What exactly do you want to do?

I just want to create clips from a video I recorded but I want to stream copy the video as to keep the settings from that same video

[ProWo]

Use clever Ffmpeg-GUI (freeware) or Videoredo Suite (payware) to cut.
The second is able to cut frame accurate.

[Guernsey]

I will have to try those but mostly the former rather the latter due to it being payware.

[Hoser Rob]

I will have to try those but mostly the former rather the latter due to it being payware.

But the 2nd (payware) one does frame accurate edits, which 57ProWo is (I think) guessing that the reason it's going out of sync is that you're not doing all your cuts on I-frames. There aren't any frame accurate free video editors AFAIK.

What's the format/codec of the file? Avidemux can only do frame accurate cuts on MPEG-2 (DVD video format) or MPEG4 ASP (divx/xvid). If it's x264 or x265 (what most .mp4 or .mkv files contain), free editors don't do frame accurate editing.

[Guernsey]

It was a x264 lossless .mkv file that I planned to convert to mp4. I guess that might had been the problem however maybe I was better with a lossless .avi file instead?