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• Returning shell_exec as string PHP detecting BPM with soundtouch/soundstrech

  23 janvier 2016, par Jeff

  I am working on a php function used to upload a .wav to server (along with converting to mp3 and creating waveform image png) , and within the function I would like it to use soundtouch / soundstrech to detect the B.P.M. (Beats Per Minute). I know it will not be the most accurate but for my purposes it will be all I need.

  I was able to get the B.P.M. of a .wav file using soundtouch / soundstrech along with ffmpeg within a test.php file using deven’s php-bpm-detect wrapper But When I try to integrate it within my PHP function it returns the B.P.M. as zero.

  I am wondering if there is a simpler way to get the bpm as a string from the following shell exec without having to use a separate php library ?

  I would like to perform this and have it return as a string :

  $song_bpm = shell_exec('soundstretch ' . $file_path . ' -bpm');

  test.php (This works and returns the proper bpm :)

  <?php
  
  require "class.bpm.php";
  
  $wavfile = "38a2819c20.wav";
  
  $bpm_detect = new bpm_detect($wavfile);  
  
  $test = $bpm_detect->detectBPM();
  
  echo ' bpm of ' . $wavfile . ' is: ' . $test . ' ';
  
  ?>

  PHP Function : (returns bpm as zero)

  function upload_a_sound($user_id, $file_temp, $file_extn, $name, $uploader, $keywords) {
  
      $timecode = substr(md5(time()), 0, 10);
  
      $mp3name = 'beats/' . $timecode . '.mp3';
  
      $file_path = 'beats/' . $timecode . '.wav';
  
      move_uploaded_file($file_temp, $file_path);
  
      shell_exec('ffmpeg -i ' . $file_path . ' -vn -ar 44100 -ac 2 -ab 192k -f mp3 ' . $mp3name . ''); 
  
      require ('classAudioFile.php'); // This creates a spectogram .png file of .wav
  
      $AF = new AudioFile;
  
      $AF->loadFile($file_path);
  
      $AF->visual_width=200;
  
      $AF->visual_height=200;
  
      $AF->visual_graph_color="#c491db";
  
      $AF->visual_background_color="#000000";
  
      $AF->visual_grid=false;
  
      $AF->visual_border=false;
  
      $AF->visual_graph_mode=0;
  
      $AF->getVisualization ('images/song/' . $timecode . '.png');
  
      $imageloc = 'images/song/' . $timecode . '.png';
  
      require ('class.bpm.php'); //Deseven's class to get bpm, 
  
      $bpm_detect = new bpm_detect($file_path);  
  
      $song_bpm = $bpm_detect->detectBPM(); //when used here this returns 0
  
      mysql_query("INSERT INTO `content` VALUES ('', '', '$name', '$uploader', '$keywords', '$file_path', '$imageloc', '$mp3name', '$song_bpm')"); // I will update this to mysqli soon, for now it works
  
  }

  I also found this which works, but not when I integrate it into my function :

  // create new files, because we don't want to override the old files
  
  $wavFile = $filename . ".wav";
  
  $bpmFile = $filename . ".bpm";
  
  
  
  //convert to wav file with ffmpeg
  
  $exec = "ffmpeg -loglevel quiet -i \"" . $filename . "\" -ar 32000 -ac 1 \"" . $wavFile . "\"";
  
  $output = shell_exec($exec);
  
  
  
  // now execute soundstretch with the newly generated wav file, write the result into a file
  
  $exec = "soundstretch \"" . $wavFile . "\" -bpm  2> " . $bpmFile;
  
  shell_exec($exec);
  
  
  
  // read and parse the file 
  
  $output = file_get_contents($bpmFile);
  
  preg_match_all("!(?:^|(?<=\s))[0-9]*\.?[0-9](?=\s|$)!is", $output, $match);
  
  
  
  // don't forget to delete the new generated files
  
  unlink($wavFile);
  
  unlink($bpmFile);
  
  
  
  // here we have the bpm
  
  echo $match[0][2];

• How to get a string representation of an audio AVStream in ffmpeg ?

  14 décembre 2015, par serg66

  I’m using ffmpeg. Consider the following piece of code :

  for(i=0; inb_streams; i++) {
  
          if (pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO) {
  
              //how do I get the language of the stream?          
  
          }
  
  }

  I found out that there is a LangEntry struct in libavformat (avlanguage file), there’s also a table containing languages and their codes, seems it’s just what I need. But I don’t know how to use it. I couldn’t find any examples of its usage. There are no reference to the LangEntry neither in AVStream, nor in AVCodecContext.

• How to add backslashes to timecode string in python 2.7 in windows and osx

  7 novembre 2015, par Tandy Freeman

  To create a burnt in timecode in ffmpeg, two escaping backslashes are required on the command line as so :

  00\\:00\\:00\\:00

  Using ffprobe to find the starting timecode produces the following output with a subprocess_output

  00:00:00:00\n

  I am using rstrip() to remove the new line, but how can I create a new variable that I can pass to ffmpeg’s filter chain that will add those escaping backslashes ?

  I ultimately need my commandline to expand to something like this :

  -vf 'drawtext=fontfile=/Library/Fonts/Tuffy.ttf:fontcolor=white:timecode=00\\:00\\:00\\:00:rate=25:boxcolor=0x000000AA:box=1:fontsize=40:x=360-text_w/2:y=405'

  though of course in my script, it will just contain

  timecode=%s