1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
|
#!/usr/bin/env python
# Copyright 2017 Graham Norbury
#
# This file is part of OP25
#
# OP25 is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3, or (at your option)
# any later version.
#
# OP25 is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
# License for more details.
#
# You should have received a copy of the GNU General Public License
# along with OP25; see the file COPYING. If not, write to the Free
# Software Foundation, Inc., 51 Franklin Street, Boston, MA
# 02110-1301, USA.
from ctypes import *
import sys
import time
import threading
import socket
import errno
# OP25 defaults
PCM_RATE = 8000 # audio sample rate (Hz)
PCM_BUFFER_SIZE = 2000 # size of ALSA buffer in frames
MAX_SUPERFRAME_SIZE = 320 # maximum size of incoming UDP audio buffer
# Debug
LOG_AUDIO_XRUNS = True # log audio underruns to stderr
# Alsa PCM constants
SND_PCM_FORMAT_S8 = c_int(0)
SND_PCM_FORMAT_U8 = c_int(1)
SND_PCM_FORMAT_S16_LE = c_int(2)
SND_PCM_FORMAT_S16_BE = c_int(3)
SND_PCM_FORMAT_U16_LE = c_int(4)
SND_PCM_FORMAT_U16_BE = c_int(5)
SND_PCM_FORMAT_S24_LE = c_int(6)
SND_PCM_FORMAT_S24_BE = c_int(7)
SND_PCM_FORMAT_U24_LE = c_int(8)
SND_PCM_FORMAT_U24_BE = c_int(9)
SND_PCM_FORMAT_S32_LE = c_int(10)
SND_PCM_FORMAT_S32_BE = c_int(11)
SND_PCM_FORMAT_U32_LE = c_int(12)
SND_PCM_FORMAT_U32_BE = c_int(13)
SND_PCM_FORMAT_FLOAT_LE = c_int(14)
SND_PCM_FORMAT_FLOAT_BE = c_int(15)
SND_PCM_FORMAT_FLOAT64_LE = c_int(16)
SND_PCM_FORMAT_FLOAT64_BE = c_int(17)
SND_PCM_FORMAT_IEC958_SUBFRAME_LE = c_int(18)
SND_PCM_FORMAT_IEC958_SUBFRAME_BE = c_int(19)
SND_PCM_FORMAT_MU_LAW = c_int(20)
SND_PCM_FORMAT_A_LAW = c_int(21)
SND_PCM_FORMAT_IMA_ADPCM = c_int(22)
SND_PCM_FORMAT_MPEG = c_int(23)
SND_PCM_FORMAT_GSM = c_int(24)
SND_PCM_FORMAT_SPECIAL = c_int(31)
SND_PCM_FORMAT_S24_3LE = c_int(32)
SND_PCM_FORMAT_S24_3BE = c_int(33)
SND_PCM_FORMAT_U24_3LE = c_int(34)
SND_PCM_FORMAT_U24_3BE = c_int(35)
SND_PCM_FORMAT_S20_3LE = c_int(36)
SND_PCM_FORMAT_S20_3BE = c_int(37)
SND_PCM_FORMAT_U20_3LE = c_int(38)
SND_PCM_FORMAT_U20_3BE = c_int(39)
SND_PCM_FORMAT_S18_3LE = c_int(40)
SND_PCM_FORMAT_S18_3BE = c_int(41)
SND_PCM_FORMAT_U18_3LE = c_int(42)
SND_PCM_FORMAT_U18_3BE = c_int(43)
SND_PCM_FORMAT_S16 = c_int(2)
SND_PCM_FORMAT_U16 = c_int(4)
SND_PCM_FORMAT_S24 = c_int(6)
SND_PCM_FORMAT_U24 = c_int(8)
SND_PCM_FORMAT_S32 = c_int(10)
SND_PCM_FORMAT_U32 = c_int(12)
SND_PCM_FORMAT_FLOAT = c_int(14)
SND_PCM_FORMAT_FLOAT64 = c_int(16)
SND_PCM_FORMAT_IEC958_SUBFRAME = c_int(18)
SND_PCM_FORMAT_LAST = SND_PCM_FORMAT_U18_3BE
SND_PCM_NORMAL = c_int(0x00000000)
SND_PCM_NONBLOCK = c_int(0x00000001)
SND_PCM_STREAM_PLAYBACK = c_int(0)
SND_PCM_STREAM_CAPTURE = c_int(1)
SND_PCM_STREAM_LAST = SND_PCM_STREAM_CAPTURE
SND_PCM_ACCESS_MMAP_INTERLEAVED = c_int(0)
SND_PCM_ACCESS_MMAP_NONINTERLEAVED = c_int(1)
SND_PCM_ACCESS_MMAP_COMPLEX = c_int(2)
SND_PCM_ACCESS_RW_INTERLEAVED = c_int(3)
SND_PCM_ACCESS_RW_NONINTERLEAVED = c_int(4)
SND_PCM_ACCESS_LAST = SND_PCM_ACCESS_RW_NONINTERLEAVED
# Python CTypes wrapper to Alsa libasound2
class alsasound(object):
def __init__(self):
self.libasound = cdll.LoadLibrary("libasound.so.2")
self.c_pcm = c_void_p()
self.format = 0
self.channels = 0
self.rate = 0
self.framesize = 0
def open(self, hwdev):
b_hwdev = create_string_buffer(str.encode(hwdev))
c_stream = SND_PCM_STREAM_PLAYBACK
err = self.libasound.snd_pcm_open(byref(self.c_pcm), b_hwdev, c_stream, SND_PCM_NORMAL)
return err
def close(self):
if (self.c_pcm.value == None):
return
self.libasound.snd_pcm_close(self.c_pcm)
self.c_pcm.value = None
def setup(self, pcm_format, pcm_channels, pcm_rate, pcm_buffer_size):
if (self.c_pcm.value == None):
return
self.format = pcm_format
self.channels = pcm_channels
self.rate = pcm_rate
pcm_start_threshold = int(pcm_buffer_size * 0.75)
c_pars = (c_void_p * int(self.libasound.snd_pcm_hw_params_sizeof() / sizeof(c_void_p)))()
err = self.libasound.snd_pcm_hw_params_any(self.c_pcm, c_pars)
if err < 0:
sys.stderr.write("hw_params_any failed: %d\n" % err)
return err
err = self.libasound.snd_pcm_hw_params_set_access(self.c_pcm, c_pars, SND_PCM_ACCESS_RW_INTERLEAVED);
if err < 0:
sys.stderr.write("set_access failed: %d\n" % err)
return err
err = self.libasound.snd_pcm_hw_params_set_format(self.c_pcm, c_pars, c_uint(self.format));
if err < 0:
sys.stderr.write("set_format failed: %d\n" % err)
return err
err = self.libasound.snd_pcm_hw_params_set_channels(self.c_pcm, c_pars, c_uint(self.channels));
if err < 0:
sys.stderr.write("set_channels failed: %d\n" % err)
return err
err = self.libasound.snd_pcm_hw_params_set_rate(self.c_pcm, c_pars, c_uint(self.rate), c_int(0));
if err < 0:
sys.stderr.write("set_rate failed: %d\n" % err)
return err
err = 0 ########self.libasound.snd_pcm_hw_params_set_buffer_size(self.c_pcm, c_pars, c_ulong(pcm_buffer_size), c_int(0));
if err < 0:
sys.stderr.write("set_buffer_size failed: %d\n" % err)
return err
err = self.libasound.snd_pcm_hw_params(self.c_pcm, c_pars);
if err < 0:
sys.stderr.write("hw_params failed: %d\n" % err)
return err
self.libasound.snd_pcm_hw_params_current(self.c_pcm, c_pars)
c_bits = self.libasound.snd_pcm_hw_params_get_sbits(c_pars)
self.framesize = self.channels * c_bits/8;
c_sw_pars = (c_void_p * int(self.libasound.snd_pcm_sw_params_sizeof() / sizeof(c_void_p)))()
err = self.libasound.snd_pcm_sw_params_current(self.c_pcm, c_sw_pars)
if err < 0:
sys.stderr.write("get_sw_params_current failed: %d\n" % err)
return err
err = self.libasound.snd_pcm_sw_params_set_start_threshold(self.c_pcm, c_sw_pars, c_uint(pcm_start_threshold))
if err < 0:
sys.stderr.write("set_sw_params_start_threshold failed: %d\n" % err)
return err
err = self.libasound.snd_pcm_sw_params(self.c_pcm, c_sw_pars)
if err < 0:
sys.stderr.write("sw_params failed: %d\n" % err)
return err
ret = self.libasound.snd_pcm_prepare(self.c_pcm)
#self.dump()
return ret
def write(self, pcm_data):
datalen = len(pcm_data)
n_frames = c_ulong(datalen / self.framesize)
c_data = c_char_p(pcm_data)
ret = 0
if (self.c_pcm.value == None):
sys.stderr.write("PCM device is closed\n")
return -1
ret = self.libasound.snd_pcm_writei(self.c_pcm, cast(c_data, POINTER(c_void_p)), n_frames)
if (ret < 0):
if (ret == -errno.EPIPE): # underrun
if (LOG_AUDIO_XRUNS):
sys.stderr.write("[%f] PCM underrun\n" % time.time())
ret = self.libasound.snd_pcm_recover(self.c_pcm, ret, 1)
if (ret >= 0):
ret = self.libasound.snd_pcm_writei(self.c_pcm, cast(c_data, POINTER(c_void_p)), n_frames)
else:
ret = self.libasound.snd_pcm_prepare(self.c_pcm)
ret = self.libasound.snd_pcm_writei(self.c_pcm, cast(c_data, POINTER(c_void_p)), n_frames)
elif (ret == -errno.ESTRPIPE): # suspended
while True:
ret = self.libasound.snd_pcm_resume(self.c_pcm)
if (ret != -errno.EAGAIN):
break
time.sleep(1)
if (ret < 0):
ret = self.libasound.snd_pcm_prepare(self.c_pcm)
elif (ret < 0): # other error
ret = self.libasound.snd_pcm_prepare(self.c_pcm)
return ret
def drain(self):
ret = self.libasound.snd_pcm_drain(self.c_pcm)
if (ret == -errno.ESTRPIPE): # suspended
while True:
ret = self.libasound.snd_pcm_resume(self.c_pcm)
if (ret != -errno.EAGAIN):
break
time.sleep(1)
ret = self.libasound.snd_pcm_prepare(self.c_pcm)
def dump(self):
if (self.c_pcm.value == None):
return
c_buf_p = c_void_p()
c_str_p = c_char_p()
c_strlen = c_uint(0)
self.libasound.snd_output_buffer_open(byref(c_buf_p))
self.libasound.snd_pcm_dump_setup(self.c_pcm, c_buf_p)
c_strlen = self.libasound.snd_output_buffer_string(c_buf_p, byref(c_str_p))
sys.stderr.write("%s\n" % c_str_p.value[0:c_strlen-1])
self.libasound.snd_output_close(c_buf_p)
# OP25 thread to receive UDP audio samples and send to Alsa driver
class socket_audio(threading.Thread):
def __init__(self, udp_host, udp_port, pcm_device, **kwds):
threading.Thread.__init__(self, **kwds)
self.setDaemon(1)
self.keep_running = True
self.sock = None
self.pcm = alsasound()
self.setup_socket(udp_host, udp_port)
self.setup_pcm(pcm_device)
self.start()
return
def run(self):
while self.keep_running:
# Data received on the udp port is 320 bytes for an audio frame or 2 bytes for a flag
#
d = self.sock.recvfrom(MAX_SUPERFRAME_SIZE) # recvfrom blocks until data becomes available
if d[0]:
d_len = len(d[0])
if (d_len == 2): # flag
flag = ord(d[0][0]) + (ord(d[0][1]) << 8) # 16 bit little endian
if (flag == 0): # 0x0000 = drain pcm buffer
self.pcm.drain()
else: # audio data
self.pcm.write(d[0])
else:
break
self.close_socket()
self.close_pcm()
return
def stop(self):
self.keep_running = False
return
def setup_socket(self, udp_host, udp_port):
self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
self.sock.bind((udp_host, udp_port))
sys.stderr.write('setup_socket: %d\n' % udp_port)
return
def close_socket(self):
self.sock.close()
return
def setup_pcm(self, hwdevice):
sys.stderr.write('audio device: %s\n' % hwdevice)
err = self.pcm.open(hwdevice)
if err < 0:
sys.stderr.write('failed to open audio device: %s\n' % hwdevice)
self.pcm.dump()
self.keep_running = False
return
err = self.pcm.setup(SND_PCM_FORMAT_S16_LE.value, 1, PCM_RATE, PCM_BUFFER_SIZE)
if err < 0:
sys.stderr.write('failed to set up pcm stream\n')
self.keep_running = False
return
return
def close_pcm(self):
self.pcm.close()
return
|
