Cutting a video without re encoding using ffmpeg and nodejs (fluent-ffmpeg)

Question

I have a quick question, I'm trying to do a cloud video editor, and i want to be able to cut out video usng nodejs.

I'm using fluent-ffmpeg. Here is my code :

const cutVideo = async (sourcePath, outputPath, startTime, duration) => {
  console.log('start cut video');

  await new Promise((resolve, reject) => {
    ffmpeg(sourcePath)
      .setFfmpegPath(pathToFfmpeg)
      .setFfprobePath(ffprobe.path)
      .output(outputPath)
      .setStartTime(startTime)
      .setDuration(duration)
      .on('end', function (err) {
        if (!err) {
          console.log('conversion Done');
          resolve();
        }
      })
      .on('error', function (err) {
        console.log('error: ', err);
        reject(err);
      })
      .run();
  });
};

It's working but not optimal, and as soon as i try to edit to a long video (getting 10 min from a video instead of 1 min out) it's super long.

What i understand is that ffmpeg re encode everything, so that's why the longer the edit is the longer the process will. Is there way to cut out using node-fluent-ffmpeg without re encoding everything ?

Thanks to the community !

Answer 1

After digging in node fluent doc and the info from @szatmary, it's possible to define audio and video codec. To use the same codec and avoid re encoding all the video, simply pass copy as argument in withVideoCodec and withAudioCodec:

const ffmpeg = require('fluent-ffmpeg');
const pathToFfmpeg = require('ffmpeg-static');
const ffprobe = require('ffprobe-static');

const cutVideo = async (sourcePath, outputPath, startTime, duration) => {
  console.log('start cut video');

  await new Promise((resolve, reject) => {
    ffmpeg(sourcePath)
      .setFfmpegPath(pathToFfmpeg)
      .setFfprobePath(ffprobe.path)
      .output(outputPath)
      .setStartTime(startTime)
      .setDuration(duration)
      .withVideoCodec('copy')
      .withAudioCodec('copy')
      .on('end', function (err) {
        if (!err) {
          console.log('conversion Done');
          resolve();
        }
      })
      .on('error', function (err) {
        console.log('error: ', err);
        reject(err);
      })
      .run();
  });
};