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# Module 'sunaudio' -- interpret sun audio headers
import audio
MAGIC = '.snd'
error = 'sunaudio sound header conversion error'
# convert a 4-char value to integer
def c2i(data):
if type(data) <> type('') or len(data) <> 4:
raise error, 'c2i: bad arg (not string[4])'
bytes = audio.chr2num(data)
for i in (1, 2, 3):
if bytes[i] < 0:
bytes[i] = bytes[i] + 256
return ((bytes[0]*256 + bytes[1])*256 + bytes[2])*256 + bytes[3]
# read a sound header from an open file
def gethdr(fp):
if fp.read(4) <> MAGIC:
raise error, 'gethdr: bad magic word'
hdr_size = c2i(fp.read(4))
data_size = c2i(fp.read(4))
encoding = c2i(fp.read(4))
sample_rate = c2i(fp.read(4))
channels = c2i(fp.read(4))
excess = hdr_size - 24
if excess < 0:
raise error, 'gethdr: bad hdr_size'
if excess > 0:
info = fp.read(excess)
else:
info = ''
return (data_size, encoding, sample_rate, channels, info)
# read and print the sound header of a named file
def printhdr(file):
hdr = gethdr(open(file, 'r'))
data_size, encoding, sample_rate, channels, info = hdr
while info[-1:] == '\0':
info = info[:-1]
print 'File name: ', file
print 'Data size: ', data_size
print 'Encoding: ', encoding
print 'Sample rate:', sample_rate
print 'Channels: ', channels
print 'Info: ', `info`
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