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Examples: add audioplot plugin example
This commit is contained in:
Mathieu Duponchelle
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6cf081fa11
commit
71bb950965
2 changed files with 247 additions and 0 deletions
242
examples/plugins/python/audioplot.py
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242
examples/plugins/python/audioplot.py
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'''
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Element that transforms audio samples to video frames representing
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the waveform.
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Requires matplotlib, numpy and numpy_ringbuffer
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Example pipeline:
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gst-launch-1.0 audiotestsrc ! audioplot window-duration=0.01 ! videoconvert ! autovideosink
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'''
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import gi
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gi.require_version('Gst', '1.0')
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gi.require_version('GstBase', '1.0')
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gi.require_version('GstAudio', '1.0')
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gi.require_version('GstVideo', '1.0')
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from gi.repository import Gst, GLib, GObject, GstBase, GstAudio, GstVideo
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try:
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import numpy as np
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import matplotlib.patheffects as pe
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from numpy_ringbuffer import RingBuffer
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from matplotlib import pyplot as plt
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from matplotlib.backends.backend_agg import FigureCanvasAgg
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except ImportError:
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Gst.error('audioplot requires numpy, numpy_ringbuffer and matplotlib')
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raise
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Gst.init(None)
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AUDIO_FORMATS = [f.strip() for f in
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GstAudio.AUDIO_FORMATS_ALL.strip('{ }').split(',')]
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ICAPS = Gst.Caps(Gst.Structure('audio/x-raw',
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format=Gst.ValueList(AUDIO_FORMATS),
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layout='interleaved',
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rate = Gst.IntRange(range(1, GLib.MAXINT)),
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channels = Gst.IntRange(range(1, GLib.MAXINT))))
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OCAPS = Gst.Caps(Gst.Structure('video/x-raw',
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format='ARGB',
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width=Gst.IntRange(range(1, GLib.MAXINT)),
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height=Gst.IntRange(range(1, GLib.MAXINT)),
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framerate=Gst.FractionRange(Gst.Fraction(1, 1),
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Gst.Fraction(GLib.MAXINT, 1))))
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DEFAULT_WINDOW_DURATION = 1.0
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DEFAULT_WIDTH = 640
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DEFAULT_HEIGHT = 480
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DEFAULT_FRAMERATE_NUM = 25
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DEFAULT_FRAMERATE_DENOM = 1
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class AudioPlotFilter(GstBase.BaseTransform):
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__gstmetadata__ = ('AudioPlotFilter','Filter', \
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'Plot audio waveforms', 'Mathieu Duponchelle')
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__gsttemplates__ = (Gst.PadTemplate.new("src",
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Gst.PadDirection.SRC,
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Gst.PadPresence.ALWAYS,
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OCAPS),
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Gst.PadTemplate.new("sink",
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Gst.PadDirection.SINK,
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Gst.PadPresence.ALWAYS,
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ICAPS))
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__gproperties__ = {
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"window-duration": (float,
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"Window Duration",
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"Duration of the sliding window, in seconds",
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0.01,
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100.0,
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DEFAULT_WINDOW_DURATION,
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GObject.ParamFlags.READWRITE
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)
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}
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def __init__(self):
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GstBase.BaseTransform.__init__(self)
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self.window_duration = DEFAULT_WINDOW_DURATION
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def do_get_property(self, prop):
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if prop.name == 'window-duration':
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return self.window_duration
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else:
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raise AttributeError('unknown property %s' % prop.name)
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def do_set_property(self, prop, value):
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if prop.name == 'window-duration':
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self.window_duration = value
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else:
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raise AttributeError('unknown property %s' % prop.name)
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def do_transform(self, inbuf, outbuf):
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if not self.h:
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self.h, = self.ax.plot(np.array(self.ringbuffer),
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lw=0.5,
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color='k',
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path_effects=[pe.Stroke(linewidth=1.0,
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foreground='g'),
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pe.Normal()])
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else:
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self.h.set_ydata(np.array(self.ringbuffer))
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self.fig.canvas.restore_region(self.background)
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self.ax.draw_artist(self.h)
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self.fig.canvas.blit(self.ax.bbox)
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s = self.agg.tostring_argb()
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outbuf.fill(0, s)
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outbuf.pts = self.next_time
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outbuf.duration = self.frame_duration
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self.next_time += self.frame_duration
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return Gst.FlowReturn.OK
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def __append(self, data):
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arr = np.array(data)
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end = self.thinning_factor * int(len(arr) / self.thinning_factor)
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arr = np.mean(arr[:end].reshape(-1, self.thinning_factor), 1)
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self.ringbuffer.extend(arr)
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def do_generate_output(self):
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inbuf = self.queued_buf
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_, info = inbuf.map(Gst.MapFlags.READ)
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res, data = self.converter.convert(GstAudio.AudioConverterFlags.NONE,
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info.data)
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data = memoryview(data).cast('i')
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nsamples = len(data) - self.buf_offset
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if nsamples == 0:
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self.buf_offset = 0
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inbuf.unmap(info)
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return Gst.FlowReturn.OK, None
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if self.cur_offset + nsamples < self.next_offset:
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self.__append(data[self.buf_offset:])
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self.buf_offset = 0
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self.cur_offset += nsamples
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inbuf.unmap(info)
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return Gst.FlowReturn.OK, None
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consumed = self.next_offset - self.cur_offset
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self.__append(data[self.buf_offset:self.buf_offset + consumed])
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inbuf.unmap(info)
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_, outbuf = GstBase.BaseTransform.do_prepare_output_buffer(self, inbuf)
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ret = self.do_transform(inbuf, outbuf)
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self.next_offset += self.samplesperbuffer
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self.cur_offset += consumed
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self.buf_offset += consumed
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return ret, outbuf
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def do_transform_caps(self, direction, caps, filter_):
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if direction == Gst.PadDirection.SRC:
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res = ICAPS
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else:
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res = OCAPS
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if filter_:
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res = res.intersect(filter_)
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return res
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def do_fixate_caps(self, direction, caps, othercaps):
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if direction == Gst.PadDirection.SRC:
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return othercaps.fixate()
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else:
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so = othercaps.get_structure(0).copy()
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so.fixate_field_nearest_fraction("framerate",
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DEFAULT_FRAMERATE_NUM,
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DEFAULT_FRAMERATE_DENOM)
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so.fixate_field_nearest_int("width", DEFAULT_WIDTH)
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so.fixate_field_nearest_int("height", DEFAULT_HEIGHT)
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ret = Gst.Caps.new_empty()
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ret.append_structure(so)
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return ret.fixate()
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def do_set_caps(self, icaps, ocaps):
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in_info = GstAudio.AudioInfo()
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in_info.from_caps(icaps)
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out_info = GstVideo.VideoInfo()
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out_info.from_caps(ocaps)
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self.convert_info = GstAudio.AudioInfo()
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self.convert_info.set_format(GstAudio.AudioFormat.S32,
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in_info.rate,
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in_info.channels,
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in_info.position)
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self.converter = GstAudio.AudioConverter.new(GstAudio.AudioConverterFlags.NONE,
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in_info,
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self.convert_info,
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None)
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self.fig = plt.figure()
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dpi = self.fig.get_dpi()
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self.fig.patch.set_alpha(0.3)
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self.fig.set_size_inches(out_info.width / float(dpi),
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out_info.height / float(dpi))
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self.ax = plt.Axes(self.fig, [0., 0., 1., 1.])
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self.fig.add_axes(self.ax)
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self.ax.set_axis_off()
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self.ax.set_ylim((GLib.MININT, GLib.MAXINT))
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self.agg = self.fig.canvas.switch_backends(FigureCanvasAgg)
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self.h = None
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samplesperwindow = int(in_info.rate * in_info.channels * self.window_duration)
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self.thinning_factor = max(int(samplesperwindow / out_info.width - 1), 1)
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cap = int(samplesperwindow / self.thinning_factor)
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self.ax.set_xlim([0, cap])
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self.ringbuffer = RingBuffer(capacity=cap)
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self.ringbuffer.extend([0.0] * cap)
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self.frame_duration = Gst.util_uint64_scale_int(Gst.SECOND,
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out_info.fps_d,
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out_info.fps_n)
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self.next_time = self.frame_duration
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self.agg.draw()
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self.background = self.fig.canvas.copy_from_bbox(self.ax.bbox)
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self.samplesperbuffer = Gst.util_uint64_scale_int(in_info.rate * in_info.channels,
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out_info.fps_d,
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out_info.fps_n)
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self.next_offset = self.samplesperbuffer
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self.cur_offset = 0
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self.buf_offset = 0
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return True
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GObject.type_register(AudioPlotFilter)
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__gstelementfactory__ = ("audioplot", Gst.Rank.NONE, AudioPlotFilter)
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@ -1,2 +1,7 @@
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# py_videomixer plugin
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Pillow >= 5.1.0
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# audioplot plugin
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matplotlib >= 2.1.1
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numpy >= 1.14.5
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numpy_ringbuffer >= 0.2.1
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