Transcode GCS files using ffmpeg

Question

My ultimate goal is to transcode video files uploaded to one GCS bucket, transcode them for HLS using App Engine, then store them in another bucket for streaming. I started with code someone else made which closely fit my use case. Right now I just have it set up to save the files as mp4 to see if it works and I receive no error messages and is logs 'Success' to the console but when I check GCS the output file it has created is only around a kb (basically its just the metadata). I believe the issue has to do with the .pipe(remoteWriteStream, { end: true }); line and something with ffmpeg because if I instead run the line originStream.pipe(remoteWriteStream, {end: true}); to test the .pipe functionality I get what I'd expect (a copy of the file of the correct size). I've seen a lot of other people such as here use essentially the same method just with cloud functions and have success. Any idea where I went wrong?

import { Storage } from '@google-cloud/storage';

import ffmpegInstaller from '@ffmpeg-installer/ffmpeg';
import ffmpeg from 'fluent-ffmpeg';

ffmpeg.setFfmpegPath(ffmpegInstaller.path);

export default async function transcode(
  //My try
  name: String,
  bucket: String,
  suffix: String,
  size: String,

): Promise<void> {
  return new Promise((resolve, reject) => {
    const storage = new Storage();

    const originBucket = storage.bucket(bucket);
    const destinationBucket = storage.bucket('storieshls-2e4b1');

    const originFile = originBucket.file(name);
    const originStream = originFile.createReadStream();

    const remoteWriteStream = destinationBucket.file(name.replace(".MOV", ".mp4")).createWriteStream({
      metadata: {
        contentType: 'video/mp4', // This could be whatever else you are transcoding to
      },
    });

    //originStream.pipe(remoteWriteStream, {end: true});

    ffmpeg()
      .input(originStream)
      .outputOptions('-c:v copy') // Change these options to whatever suits your needs
      .outputOptions('-c:a aac')
      .outputOptions('-b:a 160k')
      .outputOptions('-f mp4')
      .outputOptions('-preset fast')
      .outputOptions('-movflags frag_keyframe+empty_moov')
      .on('start', cmdLine => {
        console.log(`[${suffix}] Started FFMpeg`, cmdLine);
      })
      .on('end', () => {
        console.log(`[${suffix}] Success!.`);
        resolve();
      })
      .on('error', (err: Error, stdout, stderr) => {
        console.log(`[${suffix}] Error:`, err.message);
        console.error('stdout:', stdout);
        console.error('stderr:', stderr);

        reject();
      })
      .pipe(remoteWriteStream, { end: true });
  });
}

score 0 · Answer 1 · answered Aug 12 '20 at 11:22

You need to generate pubic URL of GCS file and pass that url in ffmpeg function.

ffmpeg(file_url)
        .output(basename + '-1280x720.mp4')
        .videoCodec('libx264')  
        .size('1280x720')

        .output(basename + '-1920x1080.mp4')
        .videoCodec('libx264')
        .size('1920x1080')

        .on('error', function(err) {
            console.log('An error occurred: ' + err.message);
        })  
        .on('progress', function(progress) { 
            console.log('... frames: ' + progress.frames);
        })
        .on('end', function() { 
            console.log('Finished processing'); 
        })
        .run();

Transcode GCS files using ffmpeg

1 Answers1