mplayer wrapper

mplayer.py

import os
import time
import subprocess
import threading
import Queue
 
# c.f.: http://is.gd/2T1p
 
path = '/usr/bin/mplayer'
 
class MPlayerIO(object):
    
    def __init__(self, filename):
        if not self.is_path_valid(path):
            raise os.error, "%s isn't the mplayer binary." % path
        cmd = [path, '-noconsolecontrols', '-slave', filename]
        self.pipe = subprocess.Popen(cmd, bufsize=1,
            stdout=subprocess.PIPE, stdin=subprocess.PIPE,
            stderr=subprocess.STDOUT)
        self.queue = Queue.Queue()
        self.thread = threading.Thread(target=self.read)
        self.thread.start()
    
    def is_path_valid(self, path):
        return os.path.exists(path) and os.access(path, os.X_OK)
    
    def write(self, cmd):
        """Send a command to mplayer."""
        if not self.is_alive():
            raise ClosedPlayer(), "mplayer is not running."
        return self.pipe.stdin.write(cmd)
    
    def read(self):
        """Read lines from the pipe and add them to the queue."""
        while True:
            if not self.is_alive():
                return
            line = self.pipe.stdout.readline()
            if not line:
                return
            self.queue.put(line)
    
    def readline(self):
        """Read one line from the queue."""
        while True:
            if self.queue.empty():
                time.sleep(0.1)
                continue
            line = self.queue.get()
            return line
    
    def close(self):
        """Close the pipe and wait for the thread to terminate."""
        if self.is_alive():
            self.pipe.communicate('quit\n')
            self.pipe.wait()
        self.thread.join()
    
    def is_alive(self):
        return self.pipe.poll() is None
    
 
class Player(object):
    
    def __init__(self, filename):
        """Open connection to mplayer and start playback."""
        if not os.path.exists(filename):
            raise os.error, 'File not found: %s' % filename
        self.io = MPlayerIO(filename)
        while True:
            line = self.io.readline()
            if line.startswith('Failed to open '):
                raise InvalidFile(), 'Failed to open %s.' % self.filename
            if line.startswith('Starting playback...'):
                break
            if line.startswith('A: '):
                break
        self.is_started = True
        self.is_playing = True
    
    def play(self):
        """An alias for unpause()."""
        self.unpause()
    
    def pause(self):
        """Attempt to pause playback."""
        if not self.is_playing:
            return
        self.io.write('pause\n')
        self.is_playing = False
    
    def unpause(self):
        """Attempt to unpause playback."""
        if self.is_playing:
            return
        self.io.write('pause\n')
        self.is_playing = True
    
    def stop(self):
        """Attempt to stop playback."""
        self.pause()
        self.io.write('seek 0 2')
        self.is_started = False
    
    def close(self):
        """Attempt to close the player."""
        self.is_started = False
        self.is_playing = False
        self.pause()
        self.io.close()
    
 
class InvalidFile(Exception): pass
class ClosedPlayer(Exception): pass