sunaudio.py revision d482e8ad4a11c7cbe9374f449da036ad21a5ee55 
1# Module 'sunaudio' -- interpret sun audio headers
2
3MAGIC = '.snd'
4
5error = 'sunaudio sound header conversion error'
6
7
8# convert a 4-char value to integer
9
10def get_long_be(s):
11	return (ord(s[0])<<24) | (ord(s[1])<<16) | (ord(s[2])<<8) | ord(s[3])
12
13
14# read a sound header from an open file
15
16def gethdr(fp):
17	if fp.read(4) <> MAGIC:
18		raise error, 'gethdr: bad magic word'
19	hdr_size = get_long_be(fp.read(4))
20	data_size = get_long_be(fp.read(4))
21	encoding = get_long_be(fp.read(4))
22	sample_rate = get_long_be(fp.read(4))
23	channels = get_long_be(fp.read(4))
24	excess = hdr_size - 24
25	if excess < 0:
26		raise error, 'gethdr: bad hdr_size'
27	if excess > 0:
28		info = fp.read(excess)
29	else:
30		info = ''
31	return (data_size, encoding, sample_rate, channels, info)
32
33
34# read and print the sound header of a named file
35
36def printhdr(file):
37	hdr = gethdr(open(file, 'r'))
38	data_size, encoding, sample_rate, channels, info = hdr
39	while info[-1:] == '\0':
40		info = info[:-1]
41	print 'File name:  ', file
42	print 'Data size:  ', data_size
43	print 'Encoding:   ', encoding
44	print 'Sample rate:', sample_rate
45	print 'Channels:   ', channels
46	print 'Info:       ', `info`
47