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• Is there a way to use EME with ClearKey encryption for HTML5 streaming protection?

  7 June 2016, by user1152226

  I am trying to understand EME with Clear Key encryption. I am using MP4Box. From the documentation here, you specify decryption keys in an XML file that is used to encrypt/decrypt your mp4 files.
  https://gpac.wp.mines-telecom.fr/mp4box/encryption/common-encryption/

  Basically, is there any point to EME with clear key encryption and is it possible to use this to protect content?

  From my understanding, the encryption keys you specify in this XML, are the keys the clients need to use on the front end to decrypt the HTML5 audio/video streams. This means, at any time, the user could use a browser’s dev tools to get the keys.

  I suppose I could obfuscate the keys somehow, but anyone with determination would still be able to get the keys.

  The other thing I could possibly do, is combine this with stream links that expire, but that also wouldn’t project the keys.

  I think you could also re-encrypt the media periodically, or encrypt the file multiple times with different keys, but that doesn’t seem like it would scale well. Having a 1 time use key for each playback would be nice, but again, probably horribly inefficient.

  Here is an example of an XML config for specific encryption keys:

  <?xml version="1.0" encoding="UTF-8"?>
  
  <gpacdrm type="CENC AES-CTR">
  
  
  
  <drminfo type="pssh" version="1" cypheroffset="9" cypherkey="0x6770616363656E6364726D746F6F6C31" cypheriv="0x00000000000000000000000000000001">
  
  <bs id128="6770616363656E6364726D746F6F6C31"></bs>
  
  <bs value="2" bits="32"></bs>
  
  <bs id128="0x279926496a7f5d25da69f2b3b2799a7f"></bs>
  
  <bs id128="0x676cb88f302d10227992649885984045"></bs>
  
  <bs bits="8" string="CID=Toto"></bs>
  
  <bs id128="0xccc0f2b3b279926496a7f5d25da692f6"></bs>
  
  <bs id128="0xccc0f2b3b279926496a7f5d25da692d6"></bs>
  
  </drminfo>
  
  <cryptrack trackid="1" isencrypted="1" saisavedbox="senc">
  
  <key kid="0x279926496a7f5d25da69f2b3b2799a7f" value="0xccc0f2b3b279926496a7f5d25da692f6"></key>
  
  <key kid="0x676cb88f302d10227992649885984045" value="0xccc0f2b3b279926496a7f5d25da692d6"></key>
  
  </cryptrack>
  
  </gpacdrm>

• Discord.js voice stop playing audio after 10 consecutive files

  29 April 2021, by Spiralio

  I am trying to do the simple task of playing a single MP3 file when a command is run. The file is stored locally, and I have FFmpeg installed on my computer. The code below is part of my command's file:

  


  const Discord = require("discord.js");
const fs = require('fs');
const { Client, RichEmbed } = require('discord.js');
const config = require("../config.json");

let playing = undefined;
let connection = undefined;

module.exports.run = async (client, message, args, config) => {


  if (playing) playing.end()
  if (connection == undefined) await message.member.voice.channel.join().then((c) => {
    connection = c;
  })
  playing = connection.play('./sounds/sound.mp3')

}


  


  (note that this code is heavily narrowed down to single out the issue)

  


  When I run the command the first 9 times, it works perfectly - the file is played, and cuts off if it is already playing. I also want to note that the file is 2 minutes long. However, once I play the file for exactly the 10th time, the bot stops playing audio entirely - as long as all 10 times are overlapping (meaning I don't let the audio finish).

  


  What's more confusing is that if an error is passed after the bot stops playing audio, it appears in an entirely different format than the standard Discord.js errors. For example, this code does not test to see if the user is in a voice channel, so if I purposefully crash the bot by initiating the command without being in a voice channel (after running the command 10 times), the error looks like this:

  


  abort(RangeError: offset is out of bounds). Build with -s ASSERTIONS=1 for more info.
(Use `electron --trace-uncaught ...` to show where the exception was thrown)


  


  (Preceded by a bunch of unformatted code) This however, is not consistent. It seems to only appear after letting the files run entirely.

  


  The issue only fixes itself when the entire bot restarts. Any help would be appreciated.

  


• ffmpeg in bash only works on every second file

  5 August 2016, by kay

  ---

  EDIT:

  The Solution is to change the original ffmpeg-call below to the following:
  ffmpeg -nostdin -loglevel 16 -i "$dir/$var" -map_channel 0.0.0 "$left" -map_channel 0.0.1 "$right"
  where the -nostdin is the crucial thing.
  For reference see apply ffmpeg to many files (comment by macmichael01)

  ---

  I’m trying to convert all .wav-files in a given directory and it’s subdirectorys into two mono-files each with the following bash script. The crucial part is almost at the bottom - the ffmpeg call:

  #!/bin/bash
  
  # "[One] Stereo [file] to two mono [files] - stereo22mono"
  
  
  
  # Syntax ffmpeg siehe: https://trac.ffmpeg.org/wiki/AudioChannelManipulation
  
  
  
  
  
  ls -R $1 > .s22mtmp.txt
  
  
  
  while read -r line || [[ -n "$line" ]]; do
  
  
  
      var=$line
  
      tst=$var
  
      tst="${tst%:}"
  
  
  
      if [ -d "${tst%./}" ]       # is directory name
  
      then
  
          dir=$tst
  
  
  
      elif [ -f "$dir/$var" ]     # is file name
  
      then
  
          left=$dir/left_$var
  
          right=$dir/right_$var
  
  
  
          #loglevel 16 = only errors
  
          # -i ...-> input file
  
          # ffmpeg ... [SOURCE] ... [TARGET1] ... [TARGET2]
  
          ffmpeg -loglevel 16 -i "$dir/$var" -map_channel 0.0.0 "$left" -map_channel 0.0.1 "$right"
  
      fi
  
  
  
  done < .s22mtmp.txt
  
  
  
  
  
  rm .s22mtmp.txt

  It almost works - besides the fact, that it only does it’s job on only every second file, although the for-loop correctly goes through all files (watched it with echo) and calls ffmpeg.
  I thought it might be that ffmpeg has not finished it’s assigned work by the time it is asked to work on the next file and therefore just refuses, which seems to be true.
  Because I made one try with disowning every call of ffmpeg like so:

  ffmpeg -loglevel 16 -i "$dir/$var" -map_channel 0.0.0 "$left" -map_channel 0.0.1 "$right" & disown

  This worked almost, the problem was just that kind of hundreds of processes and multiple times more threads where starting to run and wouldn’t complete in a reasonable time, so I arborted. :D
  But at least it didn’t skip every second file anymore with that kind of call.

  Can anyone give me a hint, how to get this done? Would be very thankful.. it’s actually the first time I’m trying with bash scripts.
  Thanks in advance!