Can you call out to FFMPEG in a Firebase Cloud Function

Update: ffmpeg is now preinstalled in the Cloud Functions environment. For a complete list of preinstalled packages, check out https://cloud.google.com/functions/docs/reference/system-packages.

Note: you only have disk write access at /tmp/.

Option 1: use ffmpeg-fluent npm module

This module abstracts the ffmpeg command line options with an easy to use Node.js module.

const ffmpeg = require('fluent-ffmpeg');

let cmd = ffmpeg('example.mp4')
    .clone()
    .size('300x300')
    .save('/tmp/smaller-file.mp4')
    .on('end', () => {
      // Finished processing the video.
      console.log('Done');

      // E.g. return the resized video:
      res.sendFile('/tmp/smaller-file.mp4');
    });

Full code on GitHub

Option 2: invoke the ffmpeg binary directly

Because ffmpeg is already installed, you can invoke the binary and its command line options via a shell process.

const { exec } = require("child_process");

exec("ffmpeg -i example.mp4", (error, stdout, stderr) => {
  //ffmpeg logs to stderr, but typically output is in stdout.
  console.log(stderr);
});

Full code on GitHub

Option 3: upload your own binary

If you need a specific version of ffmpeg, you can include an ffmpeg binary as part of the upload and then run a shell command using something like child_process.exec. You'll need an ffmpeg binary that's compiled for the target platform (Ubuntu).

File listing with pre-compiled ffmpeg binary

./
../
index.js
ffmpeg

index.js

const { exec } = require("child_process");

exec("ffmpeg -i example.mp4", (error, stdout, stderr) => {
  //ffmpeg logs to stderr, but typically output is in stdout.
  console.log(stderr);
});

I've included two full working examples on GitHub. The examples are for Google Cloud Functions (not specifically Cloud Functions for Firebase).

While you technically can run FFMPEG on a Firebase Functions instance, you will quickly hit the small quota limits.

As per this answer, you can instead use Functions to trigger a request to GCP's more powerful App Engine or Compute Engine services. The App Engine process can grab the file from the same bucket, handle the transcoding, and upload the finished file back to the bucket. If you check the other answers at the link, one user posted a sample repo that does just that.