Esempio n. 1
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def extract_channel_fragment(channel, fromtime, totime, silence=0.):
    """
    Extract a fragment of a channel in the interval [fromtime,totime].
    Eventually, surround it by silences.

    @param channel  (Channel - IN)
    @param fromtime (float - IN) From time value in seconds.
    @param totime   (float - IN) To time value in seconds.
    @param silence  (float - IN) Duration value in seconds.

    """
    framerate = channel.get_framerate()

    # Extract the fragment of the channel
    startframe = int(fromtime*framerate)
    toframe    = int(totime*framerate)
    fragmentchannel = channel.extract_fragment(begin=startframe, end=toframe)

    # Get all the frames of this fragment
    nbframes = fragmentchannel.get_nframes()
    cf = ChannelFrames( fragmentchannel.get_frames( nbframes ) )

    # surround by silences
    if silence > 0.:
        cf.prepend_silence( silence*framerate )
        cf.append_silence(  silence*framerate )

    return Channel( 16000, 2, cf.get_frames() )
Esempio n. 2
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    def test_CreateSilence(self):
        self._sample_1.extract_channel(0)
        self._sample_2.extract_channel(0)

        channel = self._sample_1.get_channel(0)
        monofrag = ChannelFrames(channel.frames)
        monofrag.append_silence(1000)
        self.assertEqual(channel.get_nframes()+1000, len(monofrag.get_frames())/channel.get_sampwidth())
Esempio n. 3
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    def norm_length(self):
        """
        Normalize the number of frames of all the channels by appending silence at the end.

        """
        nframes = 0
        for i in xrange(len(self.channels)):
            nframes = max(nframes, self.channels[i].get_nframes())

        for i in xrange(len(self.channels)):
            if self.channels[i].get_nframes() < nframes:
                fragment = ChannelFrames(self.channels[i].frames)
                fragment.append_silence(nframes - self.channels[i].get_nframes())
                self.channels[i] = Channel(self.channels[i].get_framerate(), self.channels[i].get_sampwidth(), fragment.get_frames())