Rework transcoding

Remove some of the roundabout complexity that had built up.  Push people
toward using a single, flexible tool for most of their transcoding
needs.  Increase backend and configuration flexibility to support
user-requested format changes (e.g. for an HTML5 player); this
functionality is not yet exposed.

5 files changed, 110 insertions, 160 deletions

diff --git a/lib/class/media.interface.php b/lib/class/media.interface.php
index 617e12b5..b82b5ea8 100644
--- a/lib/class/media.interface.php
+++ b/lib/class/media.interface.php
@@ -1,8 +1,6 @@
 <?php
 /* vim:set tabstop=8 softtabstop=8 shiftwidth=8 noexpandtab: */
 /**
- * media Interface
- *
  *
  * LICENSE: GNU General Public License, version 2 (GPLv2)
  * Copyright (c) 2001 - 2011 Ampache.org All Rights Reserved
@@ -19,11 +17,6 @@
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
- *
- * @package	Ampache
- * @copyright	2001 - 2011 Ampache.org
- * @license	http://opensource.org/licenses/gpl-2.0 GPLv2
- * @link	http://www.ampache.org/
  */
 
 /**
@@ -32,51 +25,45 @@
  * This defines how the media file classes should
  * work, this lists all required functions and the expected
  * input
- *
- * @package	Ampache
- * @copyright	2001 - 2011 Ampache.org
- * @license	http://opensource.org/licenses/gpl-2.0 GPLv2
- * @link	http://www.ampache.org/
- * @see	Video
- * @see	Radio
- * @see	Random
- * @see	Song
  */
 interface media {
 
 	/**
 	 * format
 	 * 
-	 * @return
+	 * Creates the gussied-up member variables for output 
 	 */
 	public function format();
 
 	/**
-	 * native_stream
+	 * get_stream_types
 	 *
-	 * @return	mixed
+	 * Returns an array of strings; current types are 'native'
+	 * and 'transcode'
 	 */
-	public function native_stream();
+	public function get_stream_types();
 
 	/**
 	 * play_url
 	 *
-	 * @param	int $oid	ID
-	 * @return	mixed
+	 * Returns the url to stream the specified object
+	 * 
 	 */
 	public static function play_url($oid);
 
 	/**
-	 * stream_cmd
+	 * get_transcode_settings
 	 *
-	 * @return	mixed
+	 * Should only be called if 'transcode' was returned by get_stream_types
+	 * Returns a raw transcode command for this item; the optional target
+	 * parameter can be used to request a specific format instead of the
+	 * default from the configuration file.
 	 */
-	public function stream_cmd();
+	public function get_transcode_settings($target = null);
 
 	/**
 	 * has_flag
 	 *
-	 * @return	mixed
 	 */
 	public function has_flag();
 
diff --git a/lib/class/radio.class.php b/lib/class/radio.class.php
index d4be4f76..a8d33ef3 100644
--- a/lib/class/radio.class.php
+++ b/lib/class/radio.class.php
@@ -188,13 +188,11 @@ class Radio extends database_object implements media {
 	} // delete
 
 	/**
-	 * native_stream
+	 * get_stream_types
 	 * This is needed by the media interface
 	 */
-	public function native_stream() {
-
-
-
+	public function get_stream_types() {
+		return array('foreign');
 	} // native_stream
 
 	/**
@@ -220,13 +218,13 @@ class Radio extends database_object implements media {
 	} // has_flag
 
 	/**
-	 * stream_cmd
-	 * Needed by the media interface
+	 * get_transcode_settings
+	 * 
+	 * This will probably never be implemented
 	 */
-	public function stream_cmd() {
-
-
-	} // stream_cmd
+	public function get_transcode_settings() {
+		return false;
+	}
 
 } //end of radio class
 
diff --git a/lib/class/song.class.php b/lib/class/song.class.php
index 70f6e881..ab38524a 100644
--- a/lib/class/song.class.php
+++ b/lib/class/song.class.php
@@ -62,11 +62,7 @@ class Song extends database_object implements media {
 	public $mbid; // MusicBrainz ID
 
 	/* Setting Variables */
-	public $_transcoded = false;
-	public $resampled = false;	
 	public $_fake = false; // If this is a 'construct_from_array' object
-	public $transcoded_from;
-	private $_transcode_cmd;
 
 	/**
 	 * Constructor
@@ -85,8 +81,9 @@ class Song extends database_object implements media {
 			foreach ($info as $key=>$value) {
 				$this->$key = $value;
 			}
-			// Format the Type of the song
-			$this->format_type();
+			$data = pathinfo($this->file);
+			$this->type = strtolower($data['extension']);
+			$this->mime = self::type_to_mime($this->type);
 		}
 
 		return true;
@@ -222,61 +219,53 @@ class Song extends database_object implements media {
 	} // fill_ext_info
 
 	/**
-	 * format_type
-	 * gets the type of song we are trying to
-	 * play, used to set mime headers and to trick
-	 * players into playing them correctly
+	 * type_to_mime
+	 *
+	 * Returns the mime type for the specified file extension/type
 	 */
-	public function format_type($override='') {
-
-		// If we pass an override for downsampling or whatever then use it
-		if (!empty($override)) {
-			$this->type = $override;
-		}
-		else {
-			$data = pathinfo($this->file);
-			$this->type = strtolower($data['extension']);
-		}
-
-		switch ($this->type) {
+	public static function type_to_mime($type) {
+		// FIXME: This should really be done the other way around.
+		// Store the mime type in the database, and provide a function
+		// to make it a human-friendly type.
+		switch ($type) {
 			case 'spx':
 			case 'ogg':
-				$this->mime = "application/ogg";
+				return 'application/ogg';
 			break;
 			case 'wma':
 			case 'asf':
-				$this->mime = "audio/x-ms-wma";
+				return 'audio/x-ms-wma';
 			break;
 			case 'mp3':
 			case 'mpeg3':
-				$this->mime = "audio/mpeg";
+				return 'audio/mpeg';
 			break;
 			case 'rm':
 			case 'ra':
-				$this->mime = "audio/x-realaudio";
+				return 'audio/x-realaudio';
 			break;
 			case 'flac';
-				$this->mime = "audio/x-flac";
+				return 'audio/x-flac';
 			break;
 			case 'wv':
-				$this->mime = 'audio/x-wavpack';
+				return 'audio/x-wavpack';
 			break;
 			case 'aac':
 			case 'mp4':
 			case 'm4a':
-				$this->mime = "audio/mp4";
+				return 'audio/mp4';
 			break;
 			case 'mpc':
-				$this->mime = "audio/x-musepack";
+				return 'audio/x-musepack';
 			break;
 			default:
-				$this->mime = "audio/mpeg";
+				return 'audio/mpeg';
 			break;
 		}
 
 		return true;
 
-	} // format_type
+	}
 
 	/**
 	 * get_album_name
@@ -923,63 +912,51 @@ class Song extends database_object implements media {
 
 	} // get_recently_played
 
-	/**
-	 * native_stream
-	 * This returns true/false if this can be natively streamed
-	 */
-	public function native_stream() {
-
-		if ($this->_transcoded) { return false; }
-
-		$conf_var 	= 'transcode_' . $this->type;
+	public function get_stream_types() {
+		$types = array();
+		$transcode = Config::get('transcode_' . $this->type);
 
-		if (Config::get($conf_var)) {
-			$this->set_transcode();
-			return false;
+		if ($transcode != 'required') {
+			$types[] = 'native';
+		}
+		if (make_bool($transcode)) {
+			$types[] = 'transcode';
 		}
 
-		return true;
-
-	} // end native_stream
-
-	/**
-	 * set_transcode
-	 *
-	 * We want to transcode, set up the variables correctly
-	 */
-	public function set_transcode() {
-		if ($this->_transcoded) { return; }
+		return $types;
+	} // end stream_types 
 
-		$conf_type      = 'transcode_' . $this->type . '_target';
-		$conf_cmd       = 'transcode_cmd_' . $this->type;
+	public function get_transcode_settings($target = null) {
+		$source = $this->type;
 
-		$this->_transcoded = true;
-		$this->transcoded_from = $this->type;
-		$this->_transcode_cmd = Config::get($conf_cmd);
-		$this->format_type(Config::get($conf_type));
-		if ($this->type == $this->transcoded_from) {
-			$this->_resampled = true;
+		if ($target) {
+			debug_event('transcode', 'Explicit format request', 5);
+		}
+		else if ($target = Config::get('encode_target_' . $source)) {
+			debug_event('transcode', 'Defaulting to configured target format for ' . $source, 5);
+		}
+		else if ($target = Config::get('encode_target')) {
+			debug_event('transcode', 'Using default target format', 5);
+		}
+		else {
+			$target = $source;
+			debug_event('transcode', 'No default target for ' . $source . ', choosing to resample', 5);
 		}
 
-		debug_event('transcode', 'Transcoding from ' . 
-			$this->transcoded_from . ' to ' . $this->type, 5);
-	}
+		debug_event('transcode', 'Transcoding from ' . $source . ' to ' . $target, 5);
 
-	/**
-	 * stream_cmd
-	 *
-	 * test if the song type streams natively and
-	 * if not returns a transcoding command from the config
-	 */
-	public function stream_cmd() {
+		$cmd = Config::get('transcode_cmd_' . $source) ?: Config::get('transcode_cmd');
+		$args = Config::get('encode_args_' . $target);
 
-		if ($this->native_stream()) {
-			return null;
+		if (!$args) {
+			debug_event('transcode', 'Target format ' . $target . ' is not properly configured', 2);
+			return false;
 		}
-		
-		return $this->_transcode_cmd;
 
-	} // end stream_cmd
+		debug_event('transcode', 'Command: ' . $cmd . ' Arguments: ' . $args, 5);
+		return array('format' => $target,
+			'command' => $cmd . ' ' . $args);
+	}
 
 } // end of song class
 ?>
diff --git a/lib/class/stream.class.php b/lib/class/stream.class.php
index 871f8394..4a25885c 100644
--- a/lib/class/stream.class.php
+++ b/lib/class/stream.class.php
@@ -142,17 +142,18 @@ class Stream {
 	 * start_transcode
 	 *
 	 * This is a rather complex function that starts the transcoding or
-	 * resampling of a song and returns the opened file handle. A reference
-	 * to the song object is passed so that the changes we make in here
-	 * affect the external object, References++
+	 * resampling of a song and returns the opened file handle.
 	 */
-	public static function start_transcode(&$song, $song_name = 0) {
+	public static function start_transcode($song) {
+		$transcode_settings = $song->get_transcode_settings();
+		// Bail out early if we're unutterably broken
+		if ($transcode_settings == false) {
+			debug_event('stream', 'Transcode requested, but get_transcode_settings failed', 2);
+			return false;
+		}
 
-		// Check to see if bitrates are set.
-		// If so let's go ahead and optimize!
 		$max_bitrate = Config::get('max_bit_rate');
 		$min_bitrate = Config::get('min_bit_rate');
-		$time = time();
 		// FIXME: This should be configurable for each output type
 		$user_sample_rate = Config::get('sample_rate');
 
@@ -161,10 +162,6 @@ class Stream {
 			$min_bitrate = $user_sample_rate;
 		}
 
-		if (!$song_name) {
-			$song_name = $song->f_artist_full . " - " . $song->title . "." . $song->type;
-		}
-
 		// Are there site-wide constraints? (Dynamic downsampling.)
 		if ($max_bitrate > 1 ) {
 			$sql = 'SELECT COUNT(*) FROM `now_playing` ' .
@@ -180,15 +177,16 @@ class Stream {
 			$results = Dba::fetch_row($db_results);
 
 			$active_streams = intval($results[0]) ?: 0;
-			debug_event('transcode', 'Active streams: ' . $active_streams, 5);
+			debug_event('stream', 'Active transcoding streams: ' . $active_streams, 5);
 
 			// We count as one for the algorithm
+			// FIXME: Should this reflect the actual bit rates?
 			$active_streams++;
 			$sample_rate = floor($max_bitrate / $active_streams);
 
 			// Exit if this would be insane
 			if ($sample_rate < ($min_bitrate ?: 8)) {
-				debug_event('transcode', 'Max bandwidth already allocated. Active streams: ' . $active_streams, 2);
+				debug_event('stream', 'Max transcode bandwidth already allocated. Active streams: ' . $active_streams, 2);
 				header('HTTP/1.1 503 Service Temporarily Unavailable');
 				exit();
 			}
@@ -203,26 +201,23 @@ class Stream {
 			$sample_rate = $user_sample_rate;
 		}
 
-		debug_event('transcode', 'Configured bitrate is ' . $sample_rate, 5);
+		debug_event('stream', 'Configured bitrate is ' . $sample_rate, 5);
 
-		/* Validate the bitrate */
+		// Validate the bitrate
 		$sample_rate = self::validate_bitrate($sample_rate);
 
 		// Never upsample a song
-		if ($song->resampled && ($sample_rate * 1000) > $song->bitrate) {
-			debug_event('transcode', 'Clamping bitrate to avoid upsampling to ' . $sample_rate, 5);
+		if ($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('transcode', 'Final bitrate is ' . $sample_rate, 5);
+		debug_event('stream', 'Final transcode bitrate is ' . $sample_rate, 5);
 
 		$song_file = scrub_arg($song->file);
 
-		$transcode_command = $song->stream_cmd();
-		if ($transcode_command == null) {
-			debug_event('downsample', 'song->stream_cmd() returned null', 2);
-			return null;
-		}
+		// Finalise the command line
+		$command = $transcode_settings['command'];
 
 		$string_map = array(
 			'%FILE%'   => $song_file,
@@ -230,20 +225,20 @@ class Stream {
 		);
 
 		foreach ($string_map as $search => $replace) {
-			$transcode_command = str_replace($search, $replace, $transcode_command, $ret);
+			$command = str_replace($search, $replace, $command, $ret);
 			if (!$ret) {
 				debug_event('downsample', "$search not in downsample command", 5);
 			}
 		}
 
-		debug_event('downsample', "Downsample command: $transcode_command", 3);
+		debug_event('downsample', "Downsample command: $command", 3);
 
-		$fp = popen($transcode_command, 'rb');
-
-		// Return our new handle
-		return $fp;
+		return array(
+			'handle' => popen($command, 'rb'),
+			'format' => $transcode_settings['format']
+		);
 
-	} // start_downsample
+	}
 
 	/**
 	 * validate_bitrate
diff --git a/lib/class/video.class.php b/lib/class/video.class.php
index 22bafa19..3802048a 100644
--- a/lib/class/video.class.php
+++ b/lib/class/video.class.php
@@ -95,13 +95,9 @@ class Video extends database_object implements media {
 
 	} // format
 
-	/**
-	 * native_stream
-	 * This returns true or false on the downsampling mojo
-	 */
-	public function native_stream() {
+	public function get_stream_types() {
 
-		return true;
+		return array('native');
 
 	} // native_stream
 
@@ -126,16 +122,13 @@ class Video extends database_object implements media {
 	} // play_url
 
 	/**
-	 * stream_cmd
-	 * test and see if the video needs to be natively streamed
-	 * if not it returns the transocding command from the config file
-	 * we can't use this->type because its been formated for the downsampling
+	 * get_transcode_settings
+	 *
+	 * FIXME: Video transcoding is not implemented
 	 */
-	public function stream_cmd() {
-
-
-
-	} // stream_cmd
+	public function get_transcode_settings($target = null) {
+		return false;
+	}
 
 	/**
 	 * has_flag