I'm writing a simple player in python using the pyaudio Library, with some basic functionalities, such start play, pause and start position. I started working on the first example of the Documentation:
import pyaudio
import wave
import sys
CHUNK = 1024
if len(sys.argv) < 2:
print("Plays a wave file.\n\nUsage: %s filename.wav" % sys.argv[0])
sys.exit(-1)
wf = wave.open(sys.argv[1], 'rb')
# instantiate PyAudio (1)
p = pyaudio.PyAudio()
# open stream (2)
stream = p.open(format=p.get_format_from_width(wf.getsampwidth()),
channels=wf.getnchannels(),
rate=wf.getframerate(),
output=True)
# read data
data = wf.readframes(CHUNK)
# play stream (3)
while len(data) > 0:
stream.write(data)
data = wf.readframes(CHUNK)
# stop stream (4)
stream.stop_stream()
stream.close()
# close PyAudio (5)
p.terminate()
It works perfectly but I really wouldn't know where to add a frame offset to start the playback at a specific frame. I saw that there are different libraries available, but PyAudio allows me to read the raw data from the file in real time, and I need this functionality. Do you have any suggestions?
You just have to count how many bytes to move in the audio.
nbytes = wf.getsampwidth() # Gives the number of bytes per sample for 1 channel
nchannels = wf.getnchannels() # Number of channels
sample_rate = wf.getframerate() # Number of samples per second 44100 is 44100 samples per second
nbytes_per_sample_per_channel = nbytes * nchannels
nbytes_per_second = nbytes_per_sample_per_channel * sample_rate
skip_seconds = 5 # Skip 5 seconds
wf.readframes(int(skip_seconds * nbytes_per_second)) # Read data that you want to skip
Start playing the file after the offset was read
# read data
data = wf.readframes(CHUNK)
# play stream (3)
while len(data) > 0:
stream.write(data)
data = wf.readframes(CHUNK)
# stop stream (4)
stream.stop_stream()
stream.close()
# close PyAudio (5)
p.terminate()