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• libavcodec/dnxhd : Enable 12-bit DNxHR support.

  2 août 2016, par Steven Robertson

  libavcodec/dnxhd : Enable 12-bit DNxHR support.
  10- and 12-bit DNxHR use the same DC coefficient decoding process and
  
  VLC table, just with a different shift value. From SMPTE 2019-1:2016,
  
  8.2.4 DC Coefficient Decoding :
  "For 8-bit video sampling, the maximum value of η=11 and for
  
  10-/12-bit video sampling, the maximum value of η=13."
  A sample file will be uploaded to show that with this patch, things
  
  decode correctly :
  
  dnxhr_hqx_12bit_1080p_smpte_colorbars_davinci_resolve.mov
  Signed-off-by : Steven Robertson <steven@strobe.cc>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/dnxhddec.c

• "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.

• Adding chapters to MP4 files, and being identified on iOS 12 podcast app

  5 avril 2019, par Craig Francis

  I have an MP4 file, where I’ve added chapters via ffmpeg.

  But in the iOS 12 Podcasts app, from Apple, the chapters don’t appear. This should happen, as noted by idownloadblog.com

  

  In comparison, when using QuickLook on MacOS, the list of chapters can be seen by clicking the chapters button (in the bottom right hand side of the window).

  

  And opening in QuickTime Player, while there isn’t a list of chapters to view, you can use the "View > Next Chapter" menu item.

  So I’m assuming this is a bug in iOS... but I’m wondering if there is another way to add chapters ? or if I’ve made a mistake ?

  ---

  My current process is to create a "ffmetadata" file, as noted in the ffmpeg documentation :

  ;FFMETADATA1
  
  title=Example
  
  
  
  [CHAPTER]
  
  TIMEBASE=1/1000
  
  START=0
  
  END=221913
  
  title=Chapter 1
  
  
  
  [CHAPTER]
  
  TIMEBASE=1/1000
  
  START=221913
  
  END=1169241
  
  title=Chapter 2

  https://ffmpeg.org/ffmpeg-formats.html#Metadata-1

  Then I’ve tried each of the following commands :

  ffmpeg -i 2019-01-02.mp4 -i 2019-01-02.meta -map_metadata 1 -codec copy 2019-01-02-chapters.mp4
  
  ffmpeg -i 2019-01-02.mp4 -i 2019-01-02.meta -map_metadata 1 2019-01-02-chapters.mp4
  
  ffmpeg -i 2019-01-02.mp4 -i 2019-01-02.meta -map_metadata 1 2019-01-02-chapters.mp3

  • The first one is from the ffmpeg documentation, where -codec copy means the audio file is not re-encoded.
  • The second one takes longer, while it re-encodes the audio data.
  • The third one requires re-encoding to convert it into an MP3 file (which uses ID3 tags for the chapter data).

  ---

  On a slightly unrelated note, the third party app "RSSRadio" does list the chapters, but the feature added in version 4 that allows you to "skip directly to the start of the next chapter", if the next chapter starts within the next 3 minutes, does not seem to work.