从 matplotlib 频谱图中删除微秒

Question

我一直在尝试根据 15 分钟长的 wav 文件绘制频谱图。我想我设法做到了这一点，但我无法从我的 x 轴（时间轴）中删除微秒。请问有什么帮助吗？

这是得到的频谱图：

这是我的代码：

import matplotlib.pyplot as plt
import scipy.io.wavfile as wavfile
import matplotlib.ticker as ticker
from matplotlib.dates import DateFormatter, MinuteLocator
import time 
# Prettify
import matplotlib
import datetime
matplotlib.rc('figure', figsize=(17, 5))

cmap = plt.get_cmap('plasma') # this may fail on older versions of matplotlib
vmin = -40  # hide anything below -40 dB
cmap.set_under(color='k', alpha=None)

rate, frames = wavfile.read("audio_test.wav")
fig, ax = plt.subplots()
pxx, freq, t, cax = ax.specgram(frames[:, 0], # first channel
                                Fs=rate,      # to get frequency axis in Hz
                                cmap=cmap, vmin=vmin)
cbar = fig.colorbar(cax)
cbar.set_label('Intensity dB')
ax.axis("tight")



ax.set_xlabel('time h:mm:ss')
ax.set_ylabel('frequency kHz')

scale = 1e3                     # KHz
ticks = matplotlib.ticker.FuncFormatter(lambda x, pos: '{0:g}'.format(x/scale))
ax.yaxis.set_major_formatter(ticks)

def timeTicks(x, pos):
    d = datetime.timedelta(seconds=x)
    return str(d)
#formatter = matplotlib.ticker.FuncFormatter(timeTicks)
#ax.xaxis.set_major_formatter(formatter)

majorFormatter = matplotlib.dates.DateFormatter('%H:%M:%S') 
ax.xaxis.set_major_formatter(majorFormatter)
ax.xaxis.set_major_locator(ticker.IndexLocator(base=120, offset=60))
#ax.text(0.0, 0.1, "IndexLocator(base=0.5, offset=0.25)",
#        fontsize=14, transform=ax.transAxes)
plt.show()

Answer 1

在您编辑之前使用代码，您可以更改def timeTicks(x, pos)的return在：

return str(d)[:7]

从 matplotlib 频谱图中删除微秒

Remove the microseconds from matplotlib spectrogram

python

matplotlib

spectrogram