#!/usr/bin/python

# gstreamer = 0.10.9
# gnonlin = 0.10.8

import gst
import pygst
import gobject

# init the threads
gobject.threads_init()

# the main loop
myMainloop = gobject.MainLoop()

# the callbacks
def eos_cb(bus, msg):
    print '* END OF STREAM'
    myMainloop.quit()
    
def on_pad_add(composition, pad):
    converterpad = myConverter.get_compatible_pad(pad, pad.get_caps())
    pad.link(converterpad)
    
# the source audio files
file1 = '/Library/Music/file1.mp3'
file2 = '/Library/Music/file2.mp3'

# the output file
outfile = '/tmp/outfile.ogg'

# the pipeline
myPipeline = gst.Pipeline()
myBus = myPipeline.get_bus()
myBus.add_signal_watch()
myBus.connect('message::eos', eos_cb)

# the pipeline elements
myComposition = gst.element_factory_make('gnlcomposition')
myConverter = gst.element_factory_make('audioconvert')
myEncoder = gst.element_factory_make('vorbisenc')
myMux = gst.element_factory_make('oggmux')
mySink = gst.element_factory_make('filesink')

# composition sources
source1 = gst.element_factory_make('gnlfilesource', 'source1')
source2 = gst.element_factory_make('gnlfilesource', 'source2')

# setup the filesink
mySink.set_property('location', outfile)

# setup the composition pad
myComposition.connect('pad-added', on_pad_add)

# setup the composistion sources
source1.set_property('location', file1)
source1.set_property('start', 0)
source1.set_property('duration', 120 * gst.SECOND)
source1.set_property('media-start', 0)
source1.set_property('media-duration', 120 * gst.SECOND)

source2.set_property('location', file2)
source2.set_property('start', 120 * gst.SECOND)
source2.set_property('duration', 120 * gst.SECOND)
source2.set_property('media-start', 0)
source2.set_property('media-duration', 120 * gst.SECOND)

# add composition sources
myComposition.add(source1)
myComposition.add(source2)

# add the elements to the pipeline
myPipeline.add(myComposition)
myPipeline.add(myConverter)
myPipeline.add(myEncoder)
myPipeline.add(myMux)
myPipeline.add(mySink)

# link elements
gst.element_link_many(myConverter, myEncoder, myMux, mySink)

# lets do it
myPipeline.set_state(gst.STATE_PLAYING)
myMainloop.run()