/**
* start_transcode
*
* This is a rather complex function that starts the transcoding or
* resampling of a song and returns the opened file handle.
*/
public static function start_transcode($song, $type = null, $bitrate = 0)
{
debug_event('stream.class.php', 'Starting transcode for {' . $song->file . '}. Type {' . $type . '}. Bitrate {' . $bitrate . '}...', 5);
$transcode_settings = $song->get_transcode_settings($type);
// Bail out early if we're unutterably broken
if ($transcode_settings == false) {
debug_event('stream', 'Transcode requested, but get_transcode_settings failed', 2);
return false;
}
if ($bitrate == 0) {
$sample_rate = self::get_allowed_bitrate($song);
debug_event('stream', 'Configured bitrate is ' . $sample_rate, 5);
// Validate the bitrate
$sample_rate = self::validate_bitrate($sample_rate);
} else {
$sample_rate = $bitrate;
}
// Never upsample a song
if ($song->type == $transcode_settings['format'] && $sample_rate * 1000 > $song->bitrate) {
debug_event('stream', 'Clamping bitrate to avoid upsampling to ' . $sample_rate, 5);
$sample_rate = self::validate_bitrate($song->bitrate / 1000);
}
debug_event('stream', 'Final transcode bitrate is ' . $sample_rate, 5);
$song_file = scrub_arg($song->file);
// Finalise the command line
$command = $transcode_settings['command'];
$string_map = array('%FILE%' => $song_file, '%SAMPLE%' => $sample_rate);
foreach ($string_map as $search => $replace) {
$command = str_replace($search, $replace, $command, $ret);
if (!$ret) {
debug_event('downsample', "{$search} not in downsample command", 5);
}
}
debug_event('downsample', "Downsample command: {$command}", 3);
$descriptors = array(1 => array('pipe', 'w'));
if (strtoupper(substr(PHP_OS, 0, 3)) !== 'WIN') {
// Windows doesn't like to provide stderr as a pipe
$descriptors[2] = array('pipe', 'w');
}
$process = proc_open($command, $descriptors, $pipes);
return array('process' => $process, 'handle' => $pipes[1], 'stderr' => $pipes[2], 'format' => $transcode_settings['format']);
}
public static function get_image_preview($media)
{
$image = null;
$sec = $media->time >= 30 ? 30 : intval($media->time / 2);
$frame = gmdate("H:i:s", $sec);
if (AmpConfig::get('transcode_cmd') && AmpConfig::get('transcode_input') && AmpConfig::get('encode_get_image')) {
$command = AmpConfig::get('transcode_cmd') . ' ' . AmpConfig::get('transcode_input') . ' ' . AmpConfig::get('encode_get_image');
$string_map = array('%FILE%' => scrub_arg($media->file), '%TIME%' => $frame);
foreach ($string_map as $search => $replace) {
$command = str_replace($search, $replace, $command, $ret);
if (!$ret) {
debug_event('stream', "{$search} not in transcode command", 5);
}
}
$proc = self::start_process($command);
if (is_resource($proc['handle'])) {
$image = '';
do {
$image .= fread($proc['handle'], 1024);
} while (!feof($proc['handle']));
fclose($proc['handle']);
}
} else {
debug_event('stream', 'Missing transcode_cmd / encode_get_image parameters to generate media preview.', 3);
}
return $image;
}