This sample uses ffmpeg / fluent-ffmpeg and automatically converts audio files that are uploaded to Cloud Storage to FLAC file format with mono-channel audio @ 16000hz.

See file functions/index.js for the audio conversion code.

The audio conversion is performed using ffmpeg. The audio is first downloaded locally from the Cloud Storage bucket to the tmp folder using the google-cloud SDK.

The dependencies are listed in functions/package.json .

The function triggers on upload of any file to your Firebase project's default Cloud Storage bucket.

To deploy and test the sample:

• Create a Firebase project on the Firebase Console and visit the Storage tab.
• Get the code, for instance using git clone https://github.com/firebase/functions-samples
• Enter the correct directory cd functions-samples/ffmpeg-convert-audio
• Setup the CLI to use your Firebase project using firebase use --add and select your Firebase project
• Deploy your project's code using firebase deploy
• Go to the Firebase Console Storage tab and upload an audio. After a short time a converted audio with the same name but a _output.flac suffix will be created in the same folder (make sure you refresh the UI to see the new file).

• Take into account that the audio files produced should not exceed the size of the memory of your function.
• The audio conversion could take a certain amount of time, increase the timeout of your function using the cloud functions webgui so the function can run for a longer time.