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• Restreaming and transcoding a hls stream with FFMPEG.WASM fails due to tcp connection

  13 juillet 2021, par Hoang Nguyen

  I'm trying to implement a feature which is live transcoding a hls stream (h265) to another hls stream (h264) so the video can be played using html5 video player as we know that h265 is not supported on browsers. Quick summery of my tech stack :

  


  -Electron desktop app as the client.
-FFMPEG.WASM library : https://ffmpegwasm.github.io/

  


  (*) The on-the-fly transcoding is supposed to happen right on the client side.

  


  My dev enviroment :

  


  "devDependencies": { "electron": "^13.1.5", "electron-packager": "^13.0.1", "electron-winstaller": "^2.7.0" }

  


  There are 2 ways to use this library, one is as normal html script, and the other is nodejs style which I have tried both and get different errors (though they are all about connection) :

  


  (*) Regular JS way

  


  <code class="echappe-js">&lt;script async defer src=&quot;https://unpkg.com/@ffmpeg/ffmpeg@0.10.1/dist/ffmpeg.min.js&quot;&gt;&lt;/script&gt;&#xA;Play
  &#xA;&lt;script&gt;&amp;#xA; async function loadPlayerHEVC() {&amp;#xA;var resource = &amp;#x27;http://10.70.39.32:80/streams/60dd68fdc88f570012526657/stream/60dd68fdc8....526657.m3u8&amp;#x27;&amp;#xA;                    const { createFFmpeg } = FFmpeg;&amp;#xA;                    const ffmpeg = createFFmpeg({ log: true });&amp;#xA;                    const { fetchFile } = FFmpeg;&amp;#xA;                    await ffmpeg.load();&amp;#xA;                    await ffmpeg.run(&amp;#x27;-re&amp;#x27;,&amp;#x27;-i&amp;#x27;, resource, &amp;#x27;-vcodec&amp;#x27;, &amp;#x27;libx264&amp;#x27;, &amp;#x27;-acodec&amp;#x27;, &amp;#x27;copy&amp;#x27;, &amp;#x27;-f&amp;#x27; ,&amp;#x27;hls&amp;#x27;, &amp;#x27;-hls_list_size&amp;#x27;, &amp;#x27;3&amp;#x27;, &amp;#x27;-hls_wrap&amp;#x27;, &amp;#x27;5&amp;#x27;, &amp;#x27;playlist.m3u8&amp;#x27; );&amp;#xA;                    // ffmpeg.exit(0);&amp;#xA;                }&amp;#xA;            &lt;/script&gt;&#xA;
  

  


  

  


  (*) Nodejs way

  


  async function tester(url)
{
    const { createFFmpeg, fetchFile } = require('@ffmpeg/ffmpeg');
    const ffmpeg = createFFmpeg({ log: true });
    await ffmpeg.load();
    await ffmpeg.run('tcp','-re', '-i', url, '-vcodec', 'libx264', '-acodec', 'aac', '-f', 'flv', '-hls_list_size', '3', '-hls_wrap', '5', 'playlist.m3u8');
    // ffmpeg.exit(0);
}


  


  

  


  URL for testing

  


  You guys can use this public stream to reproduce the scenario : http://113.163.94.245/hls-live/livepkgr/_definst_/liveevent/thbt.m3u8

  


  Any help would be much appreciated.

  


• Normalizing with ffmpeg-normalize, slight variations in sound

  20 mai 2022, par Antti Rytsölä

  I have some flacs which I am trying to normalize for Spotify and Distrokid.

  


  I got the guide from this post

  


  ffmpeg-normalize inbound/*.flac -t -14 -lrt 11 -tp -1 -ext flac -c:a flac -of normalized/


  


  Now the problem is ( before submitting to Distrokid ) that when listening to normalized versions there seems to be light deviations, like muffling, to the sound at half a second lenghts.

  


  Small sample, towards the end.

  


  Now I'm asking for help because even though I can try different settings I still want to conform to Spotify normalization guide.

  


  The Spotify guide is as follows :

  


  Target the loudness level of your master at -14dB integrated LUFS 
and keep it below -1dB TP (True Peak) max. This is best for lossy 
formats (Ogg/Vorbis and AAC) and makes sure no extra distortion’s 
introduced in the transcoding process.

If your master’s louder than -14dB integrated LUFS, make sure 
it stays below -2dB TP (True Peak) to avoid extra distortion. This 
is because louder tracks are more susceptible to extra distortion 
in the transcoding process.


  


  and

  


   ffmpeg version N-102727-g580e168a94-tessus
 ffmpeg-normalize v1.22.8


  


  Tracks now on Spotify.

  


• How to get native frame rate of vide with FFmpex ?

  18 juin 2021, par Flame_Phoenix

  Background

  


  I have an .mp4 video and I need to get the video's frame rate. Using ffmepg (in Linux) I know I can get this information via the following command :

  


  ffprobe -v 0 -of compact=p=0 -select_streams 0 -show_entries stream=r_frame_rate 'MyVideoFIle.mp4'


  


  Which returns :

  


  r_frame_rate=24000/1001


  


  FFmpex

  


  Doing this in bash is fine, but what I really want is to use it in my Elixir application. To this end I found out about ffmpex.

  


  First I tried using FFprobe :

  


  > FFprobe.format("Devil May Cry 5 Bury the Light LITTLE V COVER.mp4")

{:ok,
 %{
   "bit_rate" => "611784",
   "duration" => "482.999000",
   "filename" => "Devil May Cry 5 Bury the Light LITTLE V COVER.mp4",
   "format_long_name" => "QuickTime / MOV",
   "format_name" => "mov,mp4,m4a,3gp,3g2,mj2",
   "nb_programs" => 0,
   "nb_streams" => 2,
   "probe_score" => 100, 
   "size" => "36936415",
   "start_time" => "0.000000",
   "tags" => %{
     "compatible_brands" => "isomiso2avc1mp41",
     "encoder" => "Lavf58.19.102",
     "major_brand" => "isom",
     "minor_version" => "512"
   }
 }}


  


  Which gives me some information, but not the frame rate.

  


  My next tentative was to use the command options :

  


  command = 
  FFmpex.new_command() 
  |> add_input_file("Devil May Cry 5 Bury the Light LITTLE V COVER.mp4") 
  |> add_video_option(???) 


  


  But the problem here is that I can't find in the documentation the video option I need to get the native frame rate. I only found vframe which is used to set the video frame rate.

  


  Question

  


  

  • How can I get the native fps of a video using ffmpex ?