maemo.org - Talk - View Single Post - [Implemented] Call recording for N900

	daperl	2010-01-22 , 01:39
	Posts: 2,427 \| Thanked: 2,986 times \| Joined on Dec 2007	#85

Originally Posted by twaelti

Bla-di-blabla or constructive feedback? It might be more helpful if you could tell me how to properly stop a recording in gstreamer/pygst
Try 0.3.0, it should be better in closing the stream after recording it. It still won't play on my Win7 x64 VLC, but perhaps it does on Ubuntu now?

Maybe just try a simple wav encoding. The following code produces a wav file that works in vlc on my Mac. If you run this, you'll notice that first buffer spewed in the probe callback is the 44 byte wav header. Also, if you want do more stuff with audio files and buffers, I recommend checking out the following standard Python packages:

wave
audioop

Love your work!

Code:

#! /usr/bin/env python

import platform
import gtk
import gst

class RecordMe:
    def __init__(self):
        window = gtk.Window(gtk.WINDOW_TOPLEVEL)
        window.set_title('A Recorder')
        window.connect('destroy', gtk.main_quit)
        vbox = gtk.VBox()
        window.add(vbox)
        self.movie_window = gtk.DrawingArea()
        vbox.add(self.movie_window)
        hbox = gtk.HBox()
        vbox.pack_start(hbox, False)
        hbox.set_border_width(10)
        hbox.pack_start(gtk.Label())
        self.button = gtk.Button('Record')
        self.button.connect('clicked', self.start_stop)
        hbox.pack_start(self.button, False)
        self.button2 = gtk.Button('Quit')
        self.button2.connect('clicked', self.exit)
        hbox.pack_start(self.button2, False)
        hbox.add(gtk.Label())
        window.show_all()
        self.machine = platform.uname()[4]

        sampleRate = 22050

        if self.machine == 'armv7l':
            self.player = gst.Pipeline('ThePipe')
            src = gst.element_factory_make('pulsesrc','src')
            self.player.add(src)
            caps = gst.element_factory_make('capsfilter', 'caps')
            caps.set_property('caps', gst.caps_from_string(
                'audio/x-raw-int,width=16,depth=16,\
                rate=%d,channels=1'%sampleRate))
            self.player.add(caps)
            enc = gst.element_factory_make('wavenc','enc')
            self.player.add(enc)
            sink = gst.element_factory_make('filesink', 'sink')
            sink.set_property('location','testme.wav')
            self.player.add(sink)
            pad = sink.get_pad('sink')
            pad.add_buffer_probe(self.doBuffer)
            src.link(caps)
            caps.link(enc)
            enc.link(sink)

        bus = self.player.get_bus()
        bus.add_signal_watch()
        bus.enable_sync_message_emission()
        bus.connect('message', self.on_message)

    def doBuffer(self, pad, buffer):
        n = len(buffer)
        if n == 44:
            print 'found WAV header'
        elif n > 0:
            self.totalAudioBytes = self.totalAudioBytes + n
        return True

    def start_stop(self, w):
        if self.button.get_label() == 'Record':
            self.totalAudioBytes = 0
            self.button.set_label('Stop')
            self.player.set_state(gst.STATE_PLAYING)
        else:
            print 'total audio bytes',self.totalAudioBytes
            self.player.set_state(gst.STATE_NULL)
            self.button.set_label('Record')

    def exit(self, widget, data=None):
        gtk.main_quit()

    def on_message(self, bus, message):
        t = message.type
        if t == gst.MESSAGE_EOS:
            self.player.set_state(gst.STATE_NULL)
            self.button.set_label('Record')
        elif t == gst.MESSAGE_ERROR:
            err, debug = message.parse_error()
            print 'Error: %s' % err, debug
            self.player.set_state(gst.STATE_NULL)
            self.button.set_label('Record')

if __name__ == '__main__':
    RecordMe()
    gtk.main()

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