/**
* @param $file_name
* @return array
* @throws ApplicationException
*/
public static function generate($file_name)
{
set_time_limit(0);
$temp_file = TempFileProvider::generate("peaks", ".raw");
$command = sprintf("%s -v quiet -i %s -ac 1 -f u8 -ar 11025 -acodec pcm_u8 %s", self::$ffmpeg_cmd, escapeshellarg($file_name), escapeshellarg($temp_file));
shell_exec($command);
if (!file_exists($temp_file)) {
throw new ApplicationException("Waveform could not be generated!");
}
$chunk_size = ceil(filesize($temp_file) / self::PEAKS_RESOLUTION);
$peaks = withOpenedFile($temp_file, "r", function ($fh) use(&$chunk_size) {
while ($data = fread($fh, $chunk_size)) {
$peak = 0;
$array = str_split($data);
foreach ($array as $item) {
$code = ord($item);
if ($code > $peak) {
$peak = $code;
}
if ($code == 255) {
break;
}
}
(yield $peak - 127);
}
});
TempFileProvider::delete($temp_file);
return $peaks;
}
