Cutting clips

The recommended way is to record many small bite-sized clips with the Recording interface and create many scenes.
You will have to do less re-takes due to mistakes and having multiple scenes allows adding transitions inbetween.

If this is unfeasible and you already have a long recording that you would like to split after the fact, you can use the following script:

cut.ts
tsx
import { $ } from"bun";
import { existsSync, readdirSync, renameSync, rmSync } from"fs";
import { join } from"path";
import {
 ALTERNATIVE1_PREFIX,
 ALTERNATIVE2_PREFIX,
 CAPTIONS_PREFIX,
 DISPLAY_PREFIX,
 WEBCAM_PREFIX,
} from"./config/cameras";
constcompositionId= process.argv[2];
if (!compositionId) {
thrownewError("Expected composition ID as first argument");
}
console.log("Composition ID", compositionId);
consttimestamp= process.argv[3];
if (!timestamp) {
thrownewError("Expected timestamp as second argument");
}
consttrimPoint= process.argv[4];
if (!trimPoint) {
thrownewError("Expected trim point as third argument");
}
console.log("Timestamp", timestamp);
console.log("Trim point", trimPoint);
constfolder=join("public", compositionId);
constfiles=readdirSync(folder);
constwebcamFile= files.find((f) => f.startsWith(`webcam${timestamp}`));
if (!webcamFile) {
thrownewError(
`Expected file ${compositionId}/webcam${timestamp}.* to exist`,
 );
}
constwebcamTimestamp= webcamFile.match(/\d{1,14}/g)?.[0] ??null;
if (!webcamTimestamp) {
thrownewError(
`Expected file ${compositionId}/webcam${timestamp}.* to have timestamp ${timestamp}`,
 );
}
constallFilesWithTimestamp= files.filter((f) => {
return (
 f.startsWith(`${WEBCAM_PREFIX}${timestamp}`) ||
 f.startsWith(`${DISPLAY_PREFIX}${timestamp}`) ||
 f.startsWith(`${ALTERNATIVE1_PREFIX}${timestamp}.mp4`) ||
 f.startsWith(`${ALTERNATIVE2_PREFIX}${timestamp}.mp4`)
 );
});
constallTimestamps= [
...newSet(
 files.map((f) => {
return f.match(/\d{1,14}/g)?.[0] ??null;
 }),
 ),
];
consttimestampBefore=Number(
 allTimestamps.filter((t) =>Number(t) <Number(webcamTimestamp) ??null) ??
"0",
);
constnewTimestamp=
 (Number(webcamTimestamp) - timestampBefore) /2+ timestampBefore;
for (constfileof allFilesWithTimestamp) {
constnewFile= file.replace(
newRegExp(`${webcamTimestamp}`),
String(newTimestamp),
 );
// Create video before trim point
await$`bunx ffmpeg -i ${file} -t ${trimPoint} -c:v copy -c:a copy ${newFile}`.cwd(
 folder,
 );
// Create video after trim point
consttemporaryFile=`temp-${newFile}`;
await$`bunx ffmpeg -ss ${trimPoint} -accurate_seek -i ${file} ${temporaryFile}`.cwd(
 folder,
 );
rmSync(join(folder, file));
renameSync(join(folder, temporaryFile), join(folder, file));
}
// Remove the captions file
constcaptionsFile=join(folder, `${CAPTIONS_PREFIX}${timestamp}.json`);
if (existsSync(captionsFile)) {
rmSync(captionsFile);
}

The following is a destructive action - commit your changes before you run this.

To use this script, find the file that you would like to split, e.g. my-video/webcam123456789012345.mp4.
Execute the following on the command line:

shell
bun cut.ts my-video 123456789012345 2.0
# ^ comp ^timestamp ^ cut point in seconds

This will split all recordings into two.
It will also delete the captions file – to regenerate it, run:

shell
bun sub.ts

Now, in the Studio, add a new scene after the one you just edited.

We plan on adding a GUI shortcut for this workflow in the future.