Lib/sunaudio.py

   1 # Module 'sunaudio' -- interpret sun audio headers
   2
   3 MAGIC = '.snd'
   4
   5 error = 'sunaudio sound header conversion error'
   6
   7
   8 # convert a 4-char value to integer
   9
  10 def 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
  16 def 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
  36 def 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`