Crackling in encoded video

hi, i’ve been using shotcut for a little while and have encounterd a problem that i haven’t had before.
i have made a recording of my terrible piano playing with a logitect C920 HD webcam using microsoft camera app on my laptop, the audio line in is from a beheringer usb audio interface with two condenser mics, all other inputs in windows are disabled.

when i run the video throught shotcut the end resulting encoded video has a crackeling sound in certain places when played back, like the sound you get when skipping trough the timeline in shotcut. the original video has no clipping and doesnt have this crackeling.

laptop: Acer Swift 3
Win 10
core i5-8250U 8th gen
intel uhd 620 graphics
8gb ram
250gb ssd

original video format:
1920 x 1080 24.05fps variable
bit rate 192kbs
audio sample rate 48.000khz

encoder option:
recode vodeo to edit friendly : yes smallest size , same result on meduim and large settings
no crackeling on edit friendy converted video if played back.

newest shotcut version, tried the beta same issue.

things i have tried:

  • after recoding to edit friendly format, no filters added just save as mp4 aac default, crackeling present.

  • disable video, convert to wav crackeling present.

  • encode different video/audio format same result.

  • tried beta version same result

  • tried on different older laptop, same result

  • tried different software avidmux no crackeling.

things i guess it could be:

  1. my original video is corrupted/broken but sounds fine.
  2. my computer is causing the problem.
  3. shotcut doesnt like my piano playing!
  4. microsoft camera app causing the problem.

i have a few other recordings that are or seem to be fine.
i can supply the original and encoded files if you wish to try them on your computer.
many thanks!

Try disabling parallel processing. That might fix the crackling.


i will give it a try and see how i get on. thanks

hi, ive tried with parralell processing turned off but im still getting the same issue.
any other things i could try?

That’s all I could think of.:disappointed:

Check your audio level and try reducing it a little. There might be clipping.

The original video is recorded at a level of aound - 12db, no filters have been applied in shotcut the crackling doesn’t happen in the loudest parts of the track neither does it happen when the edit friendly file is played back in shotcut.
It only appears in the output encoded file.

Think I have figured out the problem and maybe found a bug?

My original video is 24 fps 1080 ( p/i not sure) I created a project 1080p 30fps input my file and convert to edit friendly. I then export the file (after loading the job into timeline) to mp4 1080p 30fps and that is where I hit the problem, something is happening when I export in 30fps from a already converted 24fps to 30fps edit friendly video, now if I play the edit friendly video the sound is fine no problems.

now the bug I think I have found is that shotcut converts my 24fps mp4 video to 30fps mp4 (small size) edit friendly, then exporting it converts it again causing some sound issue/ frame rate issue.

So the fix was to match the original video frame rate with the project frame rate and that was it no sound issue.

Now you may ask if im not adding any filters what’s the point of running it through shotcut, well I stopped using filters because I thought it was the cause of the sound issue but it wasn’t.

Convert to Edit-friendly does not convert your clip to the project’s frame rate. It tries to retain as much of the the source attributes as possible like resolution, aspect ratio, sample rate, bit depth, etc. However, it does typically convert variable frame rate to constant. It is mainly about that removing variable frame rate and using a format and encoding that is faster and more accurate to seek.

Are you also changing the frame rate in the Export panel?

I left it at 30fps when i exported it, not thinking anything of it or that it would be the cause of the problem in the end.

I was using youcam 8 by cyberlink until the trial ran out, the recoded video was locked at 30fps, I then tried the windows camera app that must only record at 24 fps.

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