# Sound first — cuts without pauses

> A new Sound first transition: the next clip's sound starts before the picture changes, so a cut never lands in a pause. AI editing adds it on its own.

Source: https://docs.slicer.media/en/changelog/sound-first/

## A new Sound first transition

This is how professional editors cut speech: the next clip's sound starts a split second earlier, the previous picture holds a moment longer and changes on the first words of the new sentence. The cut never lands in a pause, the speech flows evenly, and the picture change is barely noticeable.

**Sound first** is the first tile in the **Transition** panel and in the **Library**. Its duration is how far the picture lags behind the sound: 0.3 s, 0.5 s (default), 0.65 s or 0.8 s. The cut shows up in the preview right away — on the web and in the app.

## AI editing adds it on its own

At speech cuts where the picture visibly changes — another take, another source — Slicer adds **Sound first** on its own and picks the lag by the first word of the new clip. Where an abrupt cut is the point, the director keeps a straight cut. You can remove or change any of these cuts like a regular transition.

## API and MCP

The `tune_block` and `set_all_transitions` operations accept a new `jcut` transition kind with a duration from 0.15 to 1 s.

[Transitions between clips](https://docs.slicer.media/en/guide/editor/transitions/#audio-lead)