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• How to segment a video file (using FFMPEG) to "encoded" version (i.e., .mp4 is downloaded from one our CDN servers) in which each chunk must be 4MB ?

  13 janvier 2019, par Danyal Zia

  I am using FFMPEG command-line/terminal tool. I have a video in .mp4 format. I am well educated on the segmentation of videos in terms of length/duration, however, I want to segment the chunks of the "encoded/transcoded" version of the video (which I downloaded from our CDN in.mp4) to 4MB (4000000 Bytes), except the last one, which will vary in size (i.e., to encode/decode the video fully). If I am having trouble explaining what I am seeking, then just know I have no interest in segmenting the video in terms of duration/length, as this is irrelevant for me.

  To explain the scenario : I have two copies of the same video. The one is "original" and the second video is the one that I downloaded from the server/CDN. The second video turns out to be corrupted (despite the fact that the video is downloaded successfully, and has the same length/duration) ; it stops playing around 1:12 minutes, even though the seeker/slider keeps progressing until somewhere around 1:45 minutes where the video and audio start to work again.

  I have done the binary comparison (using "fc" in CMD) of these two videos, and they are not the same at all.

  In a nutshell : I think I need to "encode" the corrupted .mp4 video, and then segment the encoded data to multiple versions of 4MB. I don’t know how can I do it from FFMPEG.

  If anything isn’t clear, then ask as many questions you want.

  Thank you for reading !

  Edit : The following seems to work, however, not all the chunks are equivalent to 4MB. What is a something I am doing the wrong way ?

  ffmpeg -i "original.mp4" -b:v 1000000 -g 60 -hls_time 2 -hls
_list_size 0 -hls_segment_size 4000000 output.m3u8

• "Invalid or unexpected token" error when trying to execute ffmpeg build on lambda

  4 janvier 2019, par almarc

  I have a node.js script that uses ffmpeg to convert mp4 downloaded from YT to mp3 and save to Amazon S3. Uploading using the serverless framework. The "ffmpeg" file is included in the main directory (with .yml), downloaded from here :
  https://johnvansickle.com/ffmpeg/

  The code :

  'use strict'
  
  process.env.PATH = process.env.PATH + ':/tmp/'
  
  process.env['FFMPEG_PATH'] = '/tmp/ffmpeg';
  
  const BIN_PATH = process.env['LAMBDA_TASK_ROOT']
  
  process.env['PATH'] = process.env['PATH'] + ':' + BIN_PATH;
  
  
  
  module.exports.download_mp3 = function (event, context, callback)
  
  {
  
    require('child_process').exec('cp /var/task/ffmpeg /tmp/.; chmod 755 
  
    /tmp/ffmpeg;', function (error, stdout, stderr) {
  
    if (error) 
  
    {
  
      console.log('An error occured', error);
  
      callback(null, null)
  
    } 
  
    else 
  
    {
  
      var ffmpeg = require('ffmpeg');
  
      const aws = require('aws-sdk')
  
      const s3 = new aws.S3()
  
      const ytdl = require('ytdl-core');
  
  
  
      function uploadFromStream(s3) {
  
        const stream = require('stream')
  
        var pass = new stream.PassThrough();
  
  
  
        var params = {Bucket: "some-bucket", Key: "some-key", Body: pass};
  
        s3.upload(params, function(err, data) {
  
          console.log(err, data);
  
        });
  
        console.log("Should be finished")
  
        callback(null)
  
      }
  
  
  
      let stream = ytdl("some-video-id", {
  
        quality: 'highestaudio',
  
        filter: 'audioonly'
  
      });
  
  
  
      ffmpeg(stream)
  
        .audioBitrate(128)
  
        .format('mp3')
  
        .on('error', (err) => console.error(err))
  
        .pipe(uploadFromStream(s3), {
  
          end: true
  
      });
  
    }})
  
  }

  When triggered, the function writes an error in logs :
  

  2019-01-04T14:50:54.525Z    21da4d49-1030-11e9-b901-0dc32b691a16     
  
  /var/task/ffmpeg:1
  
  (function (exports, require, module, __filename, __dirname) { ELF
  
  ^
  
  
  
  SyntaxError: Invalid or unexpected token
  
  at createScript (vm.js:80:10)
  
  at Object.runInThisContext (vm.js:139:10)
  
  at Module._compile (module.js:616:28)
  
  at Object.Module._extensions..js (module.js:663:10)
  
  at Module.load (module.js:565:32)
  
  at tryModuleLoad (module.js:505:12)
  
  at Function.Module._load (module.js:497:3)
  
  at Module.require (module.js:596:17)
  
  at require (internal/module.js:11:18)
  
  at /var/task/download.js:17:18

  It’s, most definetely, an error in the "ffmpeg" file I’ve mentioned above (link provided). But I don’t know what’s the exact issue, I followed the first answer here : https://stackoverflow.com/questions/47882810/lambda-not-connecting-to-ffmpeg to include the ffmpeg build.

• FFMPEG - Is there a way to remove "metadata" from .MKVs ?

  1er janvier 2019, par smirnoval

  I’ve got a Matroska Media Container file (.MKV) ; summarizing it with "MediaInfo" shows it’s gotten a few text streams (I guess they’re subtitles, although they’re not shown during VLC Media Player playback), and summarizing it with MKVToolNix shows all these ’substitles’ along other weird entries.

  I know I can use the latter program to actually "save" the .MKV file without unnecessary data (everything except the Video and Audio), but I’ve never been a fan of those kinds of tools and would like to know if there’s actually a way to remove unnecessary data with FFMPEG’s command lines. All I need is the Video and Audio datas in the .MKV to later convert it into either a HEVC or AVC codec containers.
  (if there’s a command that can do all that in one go, please let me know)

  Thanks a lot.