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Guido van Rossum17ed1ae1993-06-01 13:21:04 +00001# This module contains several routines that help recognizing sound
2# files.
3#
4# Function whathdr() recognizes various types of sound file headers.
5# It understands almost all headers that SOX can decode.
6#
7# The return tuple contains the following items, in this order:
8# - file type (as SOX understands it)
9# - sampling rate (0 if unknown or hard to decode)
10# - number of channels (0 if unknown or hard to decode)
11# - number of frames in the file (-1 if unknown or hard to decode)
12# - number of bits/sample, or 'U' for U-LAW, or 'A' for A-LAW
13#
14# If the file doesn't have a recognizable type, it returns None.
15# If the file can't be opened, IOError is raised.
16#
17# To compute the total time, divide the number of frames by the
18# sampling rate (a frame contains a sample for each channel).
19#
20# Function whatraw() calls the "whatsound" program and interprets its
21# output. You'll have to guess the sampling rate by listening though!
22#
23# Function what() calls whathdr() and if it doesn't recognize the file
24# then calls whatraw().
25#
26# Finally, the function test() is a simple main program that calls
27# what() for all files mentioned on the argument list. For directory
28# arguments it calls what() for all files in that directory. Default
29# argument is "." (testing all files in the current directory). The
30# option -r tells it to recurse down directories found inside
31# explicitly given directories.
32#
33# The file structure is top-down except that the test program and its
34# subroutine come last.
35
36
37#------------------------------------------------------#
38# Guess the type of any sound file, raw or with header #
39#------------------------------------------------------#
40
41def what(filename):
42 res = whathdr(filename)
43 if not res:
44 res = whatraw(filename)
45 return res
46
47
48#-----------------------------#
49# Guess the type of raw sound #
50#-----------------------------#
51
52def whatraw(filename):
53 # Assume it's always 1 channel, byte-sized samples
54 # Don't assume anything about the rate
55 import os
56 from stat import ST_SIZE
57 # XXX "whatsound" should be part of the distribution somehow...
58 cmd = 'whatsound ' + filename + ' 2>/dev/null'
Guido van Rossum5cfa5df1993-06-23 09:30:50 +000059 cmd = 'PATH=$PATH:/ufs/guido/bin/sgi\n' + cmd
Guido van Rossum17ed1ae1993-06-01 13:21:04 +000060 pipe = os.popen(cmd, 'r')
61 data = pipe.read()
62 sts = pipe.close()
63 if sts:
64 return None
65 if data[:13] == '-t raw -b -s ':
66 type = 'sb'
67 sample_size = 8
68 elif data[:13] == '-t raw -b -u ':
69 type = 'ub'
70 sample_size = 8
71 elif data[:13] == '-t raw -b -U ':
72 type = 'ul'
73 sample_size = 'U'
74 else:
75 return None
76 try:
77 frame_count = os.stat(filename)[ST_SIZE]
78 except IOError:
79 frame_count = -1
80 return type, 0, 1, frame_count, sample_size
81
82
83#-------------------------#
84# Recognize sound headers #
85#-------------------------#
86
87def whathdr(filename):
88 f = open(filename, 'r')
89 h = f.read(512)
90 for tf in tests:
91 res = tf(h, f)
92 if res:
93 return res
94 return None
95
96
97#-----------------------------------#
98# Subroutines per sound header type #
99#-----------------------------------#
100
101tests = []
102
103def test_aifc(h, f):
104 import aifc
105 if h[:4] <> 'FORM':
106 return None
107 if h[8:12] == 'AIFC':
108 fmt = 'aifc'
109 elif h[8:12] == 'AIFF':
110 fmt = 'aiff'
111 else:
112 return None
113 f.seek(0)
114 try:
115 a = aifc.openfp(f, 'r')
116 except (EOFError, aifc.Error):
117 return None
118 return (fmt, a.getframerate(), a.getnchannels(), \
119 a.getnframes(), 8*a.getsampwidth())
120
121tests.append(test_aifc)
122
123
124def test_au(h, f):
125 if h[:4] == '.snd':
126 f = get_long_be
127 elif h[:4] in ('\0ds.', 'dns.'):
128 f = get_long_le
129 else:
130 return None
131 type = 'au'
132 hdr_size = f(h[4:8])
133 data_size = f(h[8:12])
134 encoding = f(h[12:16])
135 rate = f(h[16:20])
136 nchannels = f(h[20:24])
137 sample_size = 1 # default
138 if encoding == 1:
139 sample_bits = 'U'
140 elif encoding == 2:
141 sample_bits = 8
142 elif encoding == 3:
143 sample_bits = 16
144 sample_size = 2
145 else:
146 sample_bits = '?'
147 frame_size = sample_size * nchannels
148 return type, rate, nchannels, data_size/frame_size, sample_bits
149
150tests.append(test_au)
151
152
153def test_hcom(h, f):
154 if h[65:69] <> 'FSSD' or h[128:132] <> 'HCOM':
155 return None
156 divisor = get_long_be(h[128+16:128+20])
157 return 'hcom', 22050/divisor, 1, -1, 8
158
159tests.append(test_hcom)
160
161
162def test_voc(h, f):
163 if h[:20] <> 'Creative Voice File\032':
164 return None
165 sbseek = get_short_le(h[20:22])
166 rate = 0
167 if 0 <= sbseek < 500 and h[sbseek] == '\1':
168 ratecode = ord(h[sbseek+4])
169 rate = int(1000000.0 / (256 - ratecode))
170 return 'voc', rate, 1, -1, 8
171
172tests.append(test_voc)
173
174
175def test_wav(h, f):
176 # 'RIFF' <len> 'WAVE' 'fmt ' <len>
177 if h[:4] <> 'RIFF' or h[8:12] <> 'WAVE' or h[12:16] <> 'fmt ':
178 return None
179 style = get_short_le(h[20:22])
180 nchannels = get_short_le(h[22:24])
181 rate = get_long_le(h[24:28])
182 sample_bits = get_short_le(h[34:36])
183 return 'wav', rate, nchannels, -1, sample_bits
184
185tests.append(test_wav)
186
187
188def test_8svx(h, f):
189 if h[:4] <> 'FORM' or h[8:12] <> '8SVX':
190 return None
191 # Should decode it to get #channels -- assume always 1
192 return '8svx', 0, 1, 0, 8
193
194tests.append(test_8svx)
195
196
197def test_sndt(h, f):
198 if h[:5] == 'SOUND':
199 nsamples = get_long_le(h[8:12])
200 rate = get_short_le(h[20:22])
201 return 'sndt', rate, 1, nsamples, 8
202
203tests.append(test_sndt)
204
205
206def test_sndr(h, f):
207 if h[:2] == '\0\0':
208 rate = get_short_le(h[2:4])
209 if 4000 <= rate <= 25000:
210 return 'sndr', rate, 1, -1, 8
211
212tests.append(test_sndr)
213
214
215#---------------------------------------------#
216# Subroutines to extract numbers from strings #
217#---------------------------------------------#
218
219def get_long_be(s):
220 return (ord(s[0])<<24) | (ord(s[1])<<16) | (ord(s[2])<<8) | ord(s[3])
221
222def get_long_le(s):
223 return (ord(s[3])<<24) | (ord(s[2])<<16) | (ord(s[1])<<8) | ord(s[0])
224
225def get_short_be(s):
226 return (ord(s[0])<<8) | ord(s[1])
227
228def get_short_le(s):
229 return (ord(s[1])<<8) | ord(s[0])
230
231
232#--------------------#
233# Small test program #
234#--------------------#
235
236def test():
237 import sys
238 recursive = 0
239 if sys.argv[1:] and sys.argv[1] == '-r':
240 del sys.argv[1:2]
241 recursive = 1
242 try:
243 if sys.argv[1:]:
244 testall(sys.argv[1:], recursive, 1)
245 else:
246 testall(['.'], recursive, 1)
247 except KeyboardInterrupt:
248 sys.stderr.write('\n[Interrupted]\n')
249 sys.exit(1)
250
251def testall(list, recursive, toplevel):
252 import sys
253 import os
254 for filename in list:
255 if os.path.isdir(filename):
256 print filename + '/:',
257 if recursive or toplevel:
258 print 'recursing down:'
259 import glob
260 names = glob.glob(os.path.join(filename, '*'))
261 testall(names, recursive, 0)
262 else:
263 print '*** directory (use -r) ***'
264 else:
265 print filename + ':',
266 sys.stdout.flush()
267 try:
268 print what(filename)
269 except IOError:
270 print '*** not found ***'