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86530b38 AT |
1 | """Routines to help recognizing sound files. |
2 | ||
3 | Function whathdr() recognizes various types of sound file headers. | |
4 | It understands almost all headers that SOX can decode. | |
5 | ||
6 | The return tuple contains the following items, in this order: | |
7 | - file type (as SOX understands it) | |
8 | - sampling rate (0 if unknown or hard to decode) | |
9 | - number of channels (0 if unknown or hard to decode) | |
10 | - number of frames in the file (-1 if unknown or hard to decode) | |
11 | - number of bits/sample, or 'U' for U-LAW, or 'A' for A-LAW | |
12 | ||
13 | If the file doesn't have a recognizable type, it returns None. | |
14 | If the file can't be opened, IOError is raised. | |
15 | ||
16 | To compute the total time, divide the number of frames by the | |
17 | sampling rate (a frame contains a sample for each channel). | |
18 | ||
19 | Function what() calls whathdr(). (It used to also use some | |
20 | heuristics for raw data, but this doesn't work very well.) | |
21 | ||
22 | Finally, the function test() is a simple main program that calls | |
23 | what() for all files mentioned on the argument list. For directory | |
24 | arguments it calls what() for all files in that directory. Default | |
25 | argument is "." (testing all files in the current directory). The | |
26 | option -r tells it to recurse down directories found inside | |
27 | explicitly given directories. | |
28 | """ | |
29 | ||
30 | # The file structure is top-down except that the test program and its | |
31 | # subroutine come last. | |
32 | ||
33 | __all__ = ["what","whathdr"] | |
34 | ||
35 | def what(filename): | |
36 | """Guess the type of a sound file""" | |
37 | res = whathdr(filename) | |
38 | return res | |
39 | ||
40 | ||
41 | def whathdr(filename): | |
42 | """Recognize sound headers""" | |
43 | f = open(filename, 'rb') | |
44 | h = f.read(512) | |
45 | for tf in tests: | |
46 | res = tf(h, f) | |
47 | if res: | |
48 | return res | |
49 | return None | |
50 | ||
51 | ||
52 | #-----------------------------------# | |
53 | # Subroutines per sound header type # | |
54 | #-----------------------------------# | |
55 | ||
56 | tests = [] | |
57 | ||
58 | def test_aifc(h, f): | |
59 | import aifc | |
60 | if h[:4] != 'FORM': | |
61 | return None | |
62 | if h[8:12] == 'AIFC': | |
63 | fmt = 'aifc' | |
64 | elif h[8:12] == 'AIFF': | |
65 | fmt = 'aiff' | |
66 | else: | |
67 | return None | |
68 | f.seek(0) | |
69 | try: | |
70 | a = aifc.openfp(f, 'r') | |
71 | except (EOFError, aifc.Error): | |
72 | return None | |
73 | return (fmt, a.getframerate(), a.getnchannels(), \ | |
74 | a.getnframes(), 8*a.getsampwidth()) | |
75 | ||
76 | tests.append(test_aifc) | |
77 | ||
78 | ||
79 | def test_au(h, f): | |
80 | if h[:4] == '.snd': | |
81 | f = get_long_be | |
82 | elif h[:4] in ('\0ds.', 'dns.'): | |
83 | f = get_long_le | |
84 | else: | |
85 | return None | |
86 | type = 'au' | |
87 | hdr_size = f(h[4:8]) | |
88 | data_size = f(h[8:12]) | |
89 | encoding = f(h[12:16]) | |
90 | rate = f(h[16:20]) | |
91 | nchannels = f(h[20:24]) | |
92 | sample_size = 1 # default | |
93 | if encoding == 1: | |
94 | sample_bits = 'U' | |
95 | elif encoding == 2: | |
96 | sample_bits = 8 | |
97 | elif encoding == 3: | |
98 | sample_bits = 16 | |
99 | sample_size = 2 | |
100 | else: | |
101 | sample_bits = '?' | |
102 | frame_size = sample_size * nchannels | |
103 | return type, rate, nchannels, data_size/frame_size, sample_bits | |
104 | ||
105 | tests.append(test_au) | |
106 | ||
107 | ||
108 | def test_hcom(h, f): | |
109 | if h[65:69] != 'FSSD' or h[128:132] != 'HCOM': | |
110 | return None | |
111 | divisor = get_long_be(h[128+16:128+20]) | |
112 | return 'hcom', 22050/divisor, 1, -1, 8 | |
113 | ||
114 | tests.append(test_hcom) | |
115 | ||
116 | ||
117 | def test_voc(h, f): | |
118 | if h[:20] != 'Creative Voice File\032': | |
119 | return None | |
120 | sbseek = get_short_le(h[20:22]) | |
121 | rate = 0 | |
122 | if 0 <= sbseek < 500 and h[sbseek] == '\1': | |
123 | ratecode = ord(h[sbseek+4]) | |
124 | rate = int(1000000.0 / (256 - ratecode)) | |
125 | return 'voc', rate, 1, -1, 8 | |
126 | ||
127 | tests.append(test_voc) | |
128 | ||
129 | ||
130 | def test_wav(h, f): | |
131 | # 'RIFF' <len> 'WAVE' 'fmt ' <len> | |
132 | if h[:4] != 'RIFF' or h[8:12] != 'WAVE' or h[12:16] != 'fmt ': | |
133 | return None | |
134 | style = get_short_le(h[20:22]) | |
135 | nchannels = get_short_le(h[22:24]) | |
136 | rate = get_long_le(h[24:28]) | |
137 | sample_bits = get_short_le(h[34:36]) | |
138 | return 'wav', rate, nchannels, -1, sample_bits | |
139 | ||
140 | tests.append(test_wav) | |
141 | ||
142 | ||
143 | def test_8svx(h, f): | |
144 | if h[:4] != 'FORM' or h[8:12] != '8SVX': | |
145 | return None | |
146 | # Should decode it to get #channels -- assume always 1 | |
147 | return '8svx', 0, 1, 0, 8 | |
148 | ||
149 | tests.append(test_8svx) | |
150 | ||
151 | ||
152 | def test_sndt(h, f): | |
153 | if h[:5] == 'SOUND': | |
154 | nsamples = get_long_le(h[8:12]) | |
155 | rate = get_short_le(h[20:22]) | |
156 | return 'sndt', rate, 1, nsamples, 8 | |
157 | ||
158 | tests.append(test_sndt) | |
159 | ||
160 | ||
161 | def test_sndr(h, f): | |
162 | if h[:2] == '\0\0': | |
163 | rate = get_short_le(h[2:4]) | |
164 | if 4000 <= rate <= 25000: | |
165 | return 'sndr', rate, 1, -1, 8 | |
166 | ||
167 | tests.append(test_sndr) | |
168 | ||
169 | ||
170 | #---------------------------------------------# | |
171 | # Subroutines to extract numbers from strings # | |
172 | #---------------------------------------------# | |
173 | ||
174 | def get_long_be(s): | |
175 | return (ord(s[0])<<24) | (ord(s[1])<<16) | (ord(s[2])<<8) | ord(s[3]) | |
176 | ||
177 | def get_long_le(s): | |
178 | return (ord(s[3])<<24) | (ord(s[2])<<16) | (ord(s[1])<<8) | ord(s[0]) | |
179 | ||
180 | def get_short_be(s): | |
181 | return (ord(s[0])<<8) | ord(s[1]) | |
182 | ||
183 | def get_short_le(s): | |
184 | return (ord(s[1])<<8) | ord(s[0]) | |
185 | ||
186 | ||
187 | #--------------------# | |
188 | # Small test program # | |
189 | #--------------------# | |
190 | ||
191 | def test(): | |
192 | import sys | |
193 | recursive = 0 | |
194 | if sys.argv[1:] and sys.argv[1] == '-r': | |
195 | del sys.argv[1:2] | |
196 | recursive = 1 | |
197 | try: | |
198 | if sys.argv[1:]: | |
199 | testall(sys.argv[1:], recursive, 1) | |
200 | else: | |
201 | testall(['.'], recursive, 1) | |
202 | except KeyboardInterrupt: | |
203 | sys.stderr.write('\n[Interrupted]\n') | |
204 | sys.exit(1) | |
205 | ||
206 | def testall(list, recursive, toplevel): | |
207 | import sys | |
208 | import os | |
209 | for filename in list: | |
210 | if os.path.isdir(filename): | |
211 | print filename + '/:', | |
212 | if recursive or toplevel: | |
213 | print 'recursing down:' | |
214 | import glob | |
215 | names = glob.glob(os.path.join(filename, '*')) | |
216 | testall(names, recursive, 0) | |
217 | else: | |
218 | print '*** directory (use -r) ***' | |
219 | else: | |
220 | print filename + ':', | |
221 | sys.stdout.flush() | |
222 | try: | |
223 | print what(filename) | |
224 | except IOError: | |
225 | print '*** not found ***' | |
226 | ||
227 | if __name__ == '__main__': | |
228 | test() |