我已经让OpenCV和PyAudio都工作了,但是我不确定如何将它们同步在一起。我无法从OpenCV获取帧速率,无法测量帧的调用时间。然而,PyAudio的基础是获取一定的采样率。我该如何同步他们以相同的速度。我想有一些标准或编解码器做的方式。(我在谷歌上试过了,只得到了假唱的信息:/)。
OpenCV帧速率
from __future__ import division
import time
import math
import cv2, cv
vc = cv2.VideoCapture(0)
# get the frame
while True:
before_read = time.time()
rval, frame = vc.read()
after_read = time.time()
if frame is not None:
print len(frame)
print math.ceil((1.0 / (after_read - before_read)))
cv2.imshow("preview", frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
else:
print "None..."
cv2.waitKey(1)
# display the frame
while True:
cv2.imshow("preview", frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
抓取和保存音频
from sys import byteorder
from array import array
from struct import pack
import pyaudio
import wave
THRESHOLD = 500
CHUNK_SIZE = 1024
FORMAT = pyaudio.paInt16
RATE = 44100
def is_silent(snd_data):
"Returns 'True' if below the 'silent' threshold"
print "\n\n\n\n\n\n\n\n"
print max(snd_data)
print "\n\n\n\n\n\n\n\n"
return max(snd_data) < THRESHOLD
def normalize(snd_data):
"Average the volume out"
MAXIMUM = 16384
times = float(MAXIMUM)/max(abs(i) for i in snd_data)
r = array('h')
for i in snd_data:
r.append(int(i*times))
return r
def trim(snd_data):
"Trim the blank spots at the start and end"
def _trim(snd_data):
snd_started = False
r = array('h')
for i in snd_data:
if not snd_started and abs(i)>THRESHOLD:
snd_started = True
r.append(i)
elif snd_started:
r.append(i)
return r
# Trim to the left
snd_data = _trim(snd_data)
# Trim to the right
snd_data.reverse()
snd_data = _trim(snd_data)
snd_data.reverse()
return snd_data
def add_silence(snd_data, seconds):
"Add silence to the start and end of 'snd_data' of length 'seconds' (float)"
r = array('h', [0 for i in xrange(int(seconds*RATE))])
r.extend(snd_data)
r.extend([0 for i in xrange(int(seconds*RATE))])
return r
def record():
"""
Record a word or words from the microphone and
return the data as an array of signed shorts.
Normalizes the audio, trims silence from the
start and end, and pads with 0.5 seconds of
blank sound to make sure VLC et al can play
it without getting chopped off.
"""
p = pyaudio.PyAudio()
stream = p.open(format=FORMAT, channels=1, rate=RATE,
input=True, output=True,
frames_per_buffer=CHUNK_SIZE)
num_silent = 0
snd_started = False
r = array('h')
while 1:
# little endian, signed short
snd_data = array('h', stream.read(1024))
if byteorder == 'big':
snd_data.byteswap()
print "\n\n\n\n\n\n"
print len(snd_data)
print snd_data
r.extend(snd_data)
silent = is_silent(snd_data)
if silent and snd_started:
num_silent += 1
elif not silent and not snd_started:
snd_started = True
if snd_started and num_silent > 1:
break
sample_width = p.get_sample_size(FORMAT)
stream.stop_stream()
stream.close()
p.terminate()
r = normalize(r)
r = trim(r)
r = add_silence(r, 0.5)
return sample_width, r
def record_to_file(path):
"Records from the microphone and outputs the resulting data to 'path'"
sample_width, data = record()
data = pack('<' + ('h'*len(data)), *data)
wf = wave.open(path, 'wb')
wf.setnchannels(1)
wf.setsampwidth(sample_width)
wf.setframerate(RATE)
wf.writeframes(data)
wf.close()
if __name__ == '__main__':
print("please speak a word into the microphone")
record_to_file('demo.wav')
print("done - result written to demo.wav")
我认为你最好使用GSreamer或ffmpeg,或者如果你在Windows上使用DirectShow。这些libs可以同时处理音频和视频,并且应该有某种多路复用器,允许您正确地混合视频和音频。
但是如果您真的想使用Opencv来实现这一点,那么您应该能够使用
VideoCapture
来获得帧速率,您是否尝试过使用this?另一种方法是将fps估计为帧数除以持续时间:
我不确定我是否理解你想在这里做什么:
在我看来,执行
after_read - before_read
只测量OpenCV加载下一帧所花的时间,而不测量fps。OpenCV并没有试图进行回放,它只是加载帧,它会尽其所能以最快的速度进行加载,我认为没有办法配置它。我认为在显示每个帧后放置一个waitKey(1/fps)
将实现您所要的。相关问题 更多 >
编程相关推荐