我想在HoloViews图中可视化当前音频在图形中。更改PyViz的pn.pane.Audio.time
值时(播放音频或更改Audio.time
时),该行应自动更新。
我的尝试:
# Python 3.7 in JupyterLab
import numpy as np
import holoviews as hv # interactive plots
hv.notebook_extension("bokeh")
import panel as pn
pn.extension()
from holoviews.streams import Stream,param
# create sound
sps = 44100 # Samples per second
duration = 10 # Duration in seconds
modulator_frequency = 2.0
carrier_frequency = 120.0
modulation_index = 2.0
time = np.arange(sps*duration) / sps
modulator = np.sin(2.0 * np.pi * modulator_frequency * time) * modulation_index
carrier = np.sin(2.0 * np.pi * carrier_frequency * time)
waveform = np.sin(2. * np.pi * (carrier_frequency * time + modulator))
waveform_quiet = waveform * 0.3
waveform_int = np.int16(waveform_quiet * 32767)
# PyViz Panel's Audio widget to play sound
audio = pn.pane.Audio(waveform_int,sample_rate=sps)
# generated plotting data
x = np.arange(11.0)
y = np.arange(11.0,0.0,-1) / 10
y[0::2] *= -1 # alternate positve-negative
# HoloViews line plot
line_plot = hv.Curve((x,y)).opts(width=500)
# should keep track of audio.time; DOES NOT WORK
Time = Stream.define('Time',t=param.Number(default=0.0,doc='A time parameter'))
time = Time(t=audio.time)
# callback to draw line when time value changes
def interactive_play(t):
return hv.VLine(t).opts(color='green')
# dynamic map plot of line for current audio time
dmap_time = hv.DynamicMap(interactive_play,streams=[time])
# display Audio pane
display(audio)
# combine plot with stream of audio.time
line_plot * dmap_time
为什么这不起作用?
由于时间设置为param.Number()
,所以我希望它能跟踪audio.time
。因此,在播放音频时,应不断调用interactive_play()
的回调,从而使Line在整个情节上移动。
这不会发生,并且该行仅保持默认值0.0(或代码执行时audio.time
的任何其他值)。
如何更新VLine
以保持跟踪audio.time
?