❓ What is it?

A J-cut is a type of cut between 2 clips on a timeline where the audio cuts to the next clip before the video does.

The key metric is the "offset" (i.e. how much earlier does the audio cut vs. the video?), typically measured in frames. The 2 most common applications of J-cuts are:

  • 1-10 frames offset for making cuts smoother: Cuts in the video can often appear "jumpy" especially if you have a lot of them. Adding a slight offset where the audio comes in earlier can make the cuts feel smoother. This creates a subliminal effect of making the video "follow" the audio.

  • 10+ frames offset as a stylistic touch: This is an artistic application of J-cuts, where the editor "sets the scene" with audio before the video comes in, e.g. hearing the sound of rain on black video before the actual footage even starts, hearing an interviewee start speaking in a documentary before switching the camera to them, etc.

Note: J-cuts are available as part of the Advanced mode in Remove Silences

🤔 How does it work?

J-cuts in FireCut are a part of the advanced "remove silences" feature.

  • You specify which audio tracks to use as guidance tracks

  • When all guidance tracks are silent, that portion of your sequence is cut out i.e., all tracks are cut. This is because you might have your "good" audio on many different tracks / clips, and they might not even by linked to your video. This does not matter for FireCut, as long as you select the right guidance audio tracks

  • You specify what J-cut offset to apply (0 frames = no J-cut) and FireCut accordingly changes where your video and audio are cut to create that offset. The offset is actually applied to the video clip, not the audio clip, so your silences will still be cut in the same places. This is done to ensure you don't accidentally cut the starts/ends of sentences.

⚙️ Settings

J-cuts only have 1 setting (as part of the review screen in Remove silences > Advanced mode):

  1. Offset: This is the number of frames by which the cut between the audio and video will be offset. A number greater than 0 will cause the audio to be cut earlier than the video by that many frames. Leave this at 0 if you don't want J-cuts.

💡 Tips for best outcomes

  • Don't use settings that will create hundreds of cuts (and result in lots of short clips), which are often undesirable and will take too much detection / processing time. For example:

    • Don't set the detection threshold (dBFS) too high. Going over higher than -30 dBFS is not recommended

    • Keep the minimum silence duration above 750ms

    • Always add some padding before cutting, this might even get rid of the shortest silences

  • Try your settings on a small portion of your sequence before processing hours of footage

  • Don't work in the timeline while FireCut is working in the background

🙋‍♂️ Common questions, issues, watch-outs

  • "It cut out my entire sequence" --> The detection threshold was too high / the tightness was too tight. Try Advanced mode with an auto-detected threshold (and move it lower if the suggested value seems too high), and set the min silence duration at least 750ms.

  • "It slows down over time when processing long sequences" --> This happens with Original and Rapid algorithms because the number of clips on your timeline increases as cuts are made, slowing down Premiere Pro. If you're experiencing very long processing times (e.g. 30+ mins), then it's a sign that:

    • You are likely cutting more silences than you need (slowdown typically happens when you're cutting 200+ silences)

    • You should try Turbo mode

  • "I had an issue with Turbo mode" --> This feature is brand new, and we want to fix whatever caused the issue for you! Please use the "Share feedback" button inside FireCut / email support@firecut.ai

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