Error: ffmpeg exited with code 1: Conversion failed!

[romualdo-ah]

Version information

• fluent-ffmpeg version: 2.0.1
• ffmpeg version: 3.4.6
• OS: Ubuntu 18.04.1

Code to reproduce

 const glob = require('glob');

function start(){

    const path = './videos/*.mp4'
    const videos = glob.sync(path);
    const output = `./output.mp4`;

 await withFluentFfmpeg();

    async function withFluentFfmpeg() {

      var Ffmpeg = require('fluent-ffmpeg');
 
      const ffmpeg = Ffmpeg();
 
      videos.map(video => ffmpeg.input(video))
      await ffmpeg.mergeToFile(output);
    }
}
start();

(note: if the problem only happens with some inputs, include a link to such an input file)

Expected results

Concatenate the videos onto one output.mp4 file

Observed results

events.js:287
throw er; // Unhandled 'error' event
^

Error: ffmpeg exited with code 1: Conversion failed!

at ChildProcess.<anonymous> (/home/r/Projects/webscrapping/node_modules/fluent-ffmpeg/lib/processor.js:167:22)
at ChildProcess.emit (events.js:310:20)
at Process.ChildProcess._handle.onexit (internal/child_process.js:275:12)

Emitted 'error' event on FfmpegCommand instance at:
at emitEnd (/home/r/Projects/webscrapping/node_modules/fluent-ffmpeg/lib/processor.js:413:16)
at endCB (/home/r/Projects/webscrapping/node_modules/fluent-ffmpeg/lib/processor.js:524:13)
at handleExit (/home/r/Projects/webscrapping/node_modules/fluent-ffmpeg/lib/processor.js:155:11)
at ChildProcess. (/home/r/Projects/webscrapping/node_modules/fluent-ffmpeg/lib/processor.js:167:11)
at ChildProcess.emit (events.js:310:20)
at Process.ChildProcess._handle.onexit (internal/child_process.js:275:12)

Checklist

• I have read the FAQ
• I tried the same with command line ffmpeg and it works correctly (hint: if the problem also happens this way, this is an ffmpeg problem and you're not reporting it to the right place)
• I have included full stderr/stdout output from ffmpeg