mirror of
https://github.com/larsimmisch/pyalsaaudio.git
synced 2026-05-23 14:55:30 +00:00
5c2a006553
Converted documentation to Sphinx. Added playwav.py git-svn-id: svn://svn.code.sf.net/p/pyalsaaudio/code/trunk@25 ec2f30ec-7544-0410-870e-f70ca00c83f0
90 lines
2.4 KiB
Python
Executable File
90 lines
2.4 KiB
Python
Executable File
#!/usr/bin/env python
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# Simple test script that plays (some) wav files
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import sys
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import struct
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import alsaaudio
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# this is all a bit simplified, and won't cope with any wav extensions
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# or multiple data chunks, but it's good enough here
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WAV_FORMAT_PCM = 1
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WAV_FORMAT_ALAW = 6
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WAV_FORMAT_MULAW = 7
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WAV_HEADER = '<4sl4s4slhhllhh4sl'
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WAV_HEADER_SIZE = struct.calcsize(WAV_HEADER)
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def _b(s):
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'Helper for 3.0 compatibility'
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if sys.version_info[0] >= 3:
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return bytes(s, 'UTF-8')
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return s
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def wav_header_unpack(data):
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(riff, riffsize, wave, fmt, fmtsize, format, nchannels, framerate,
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datarate, blockalign, bitspersample, data, datalength) \
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= struct.unpack(WAV_HEADER, data)
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print(data)
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if riff != _b('RIFF') or fmtsize != 16 or fmt != _b('fmt ') \
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or data != _b('data'):
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raise ValueError('wav header too complicated')
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return (format, nchannels, framerate, bitspersample, datalength)
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def play(device, f):
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header = f.read(WAV_HEADER_SIZE)
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format, nchannels, framerate, bitspersample, datalength \
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= wav_header_unpack(header)
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# Set attributes
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device.setchannels(nchannels)
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device.setrate(framerate)
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# We assume signed data, little endian
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if format == WAV_FORMAT_PCM:
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if bitspersample == 8:
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device.setformat(alsaaudio.PCM_FORMAT_S8)
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elif bitspersample == 16:
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device.setformat(alsaaudio.PCM_FORMAT_S16_LE)
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elif bitspersample == 24:
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device.setformat(alsaaudio.PCM_FORMAT_S24_LE)
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elif bitspersample == 32:
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device.setformat(alsaaudio.PCM_FORMAT_S32_LE)
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elif format == WAV_FORMAT_ALAW:
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device.setformat(alsaaudio.PCM_FORMAT_A_LAW)
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elif format == WAV_FORMAT_MULAW:
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device.setformat(alsaaudio.PCM_FORMAT_MU_LAW)
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else:
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raise ValueError('Unsupported format %d' % format)
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# The period size controls the internal number of frames per period.
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# The significance of this parameter is documented in the ALSA api.
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# rs = framerate / 25
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# out.setperiodsize(rs)
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data = f.read()
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while data:
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# Read data from stdin
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device.write(data)
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data = f.read()
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if __name__ == '__main__':
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if len(sys.argv) < 2:
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print('usage: playwav.py <file>')
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sys.exit(2)
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f = open(sys.argv[1], 'rb')
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device = alsaaudio.PCM(alsaaudio.PCM_PLAYBACK)
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play(device, f)
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f.close()
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