#/usr/bin/python

import pygst
pygst.require('0.10')
import gst
import gobject
import sys

def make_source(filename, caps, mediastart, start, duration):
    """ make a gnlfilesource for the given file with the given properties """
    source = gst.element_factory_make("gnlfilesource")
    source.set_property("location", filename)
    source.set_property("start", start)
    source.set_property("media-start", mediastart)
    source.set_property("duration", duration)
    source.set_property("media-duration", duration)
    source.set_property("caps", caps)
    return source

def get_compositions(filename):
    """ return the video composition and the audio composition """
    # in the videocomposition we put the video part of the file
    videocomp = gst.element_factory_make("gnlcomposition", "videocomp")

    # from 0 to 5s we put the part starting at 20s in the file
    src1 = make_source(filename, gst.caps_from_string("video/x-raw-yuv"),
                       20 * gst.SECOND,
                       0,
                       5 * gst.SECOND)

    # from 5s to 10s we put the part starting at 5s in the file
    src2 = make_source(filename, gst.caps_from_string("video/x-raw-yuv"),
                       5 * gst.SECOND,
                       5 * gst.SECOND,
                       5 * gst.SECOND)
    videocomp.add(src1, src2)

    # for audio we put 10s starting at the beginning of the file
    audiocomp = gst.element_factory_make("gnlcomposition", "audiocomp")
    src3 = make_source(filename, gst.caps_from_string("audio/x-raw-int"),
                       0, 0 * gst.SECOND, 10 * gst.SECOND)
    audiocomp.add(src3)

    return (videocomp, audiocomp)

def comp_pad_added_cb(comp, pad, sink):
    """ callback to connect to sinks """
    gst.debug("got new pad %s" % pad.get_caps().to_string())
    pad.link(sink.get_pad("sink"))

# our pipeline, mainloop and audio/video compositions
pipeline = gst.Pipeline()
mainloop = gobject.MainLoop()
vcomp, acomp = get_compositions(sys.argv[1])
pipeline.add(vcomp, acomp)

# The sinks
vsink = gst.element_factory_make("xvimagesink")
csp = gst.element_factory_make("ffmpegcolorspace")
asink = gst.element_factory_make("alsasink")
aconv = gst.element_factory_make("audioconvert")
vq = gst.element_factory_make("queue")
aq = gst.element_factory_make("queue")
pipeline.add(vsink, asink, vq, aq, csp, aconv)
vq.link(csp)
csp.link(vsink)
aq.link(aconv)
aconv.link(asink)

# connect to the compositions callback
vcomp.connect("pad-added", comp_pad_added_cb, vq)
acomp.connect("pad-added", comp_pad_added_cb, aq)


pipeline.set_state(gst.STATE_PLAYING)
# IMPORTANT : gnonlin needs a mainloop
mainloop.run()