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Diffstat (limited to 'lib/python2.7/sndhdr.py')
| -rw-r--r-- | lib/python2.7/sndhdr.py | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/lib/python2.7/sndhdr.py b/lib/python2.7/sndhdr.py new file mode 100644 index 0000000..cc2d6b8 --- /dev/null +++ b/lib/python2.7/sndhdr.py @@ -0,0 +1,228 @@ +"""Routines to help recognizing sound files. + +Function whathdr() recognizes various types of sound file headers. +It understands almost all headers that SOX can decode. + +The return tuple contains the following items, in this order: +- file type (as SOX understands it) +- sampling rate (0 if unknown or hard to decode) +- number of channels (0 if unknown or hard to decode) +- number of frames in the file (-1 if unknown or hard to decode) +- number of bits/sample, or 'U' for U-LAW, or 'A' for A-LAW + +If the file doesn't have a recognizable type, it returns None. +If the file can't be opened, IOError is raised. + +To compute the total time, divide the number of frames by the +sampling rate (a frame contains a sample for each channel). + +Function what() calls whathdr(). (It used to also use some +heuristics for raw data, but this doesn't work very well.) + +Finally, the function test() is a simple main program that calls +what() for all files mentioned on the argument list. For directory +arguments it calls what() for all files in that directory. Default +argument is "." (testing all files in the current directory). The +option -r tells it to recurse down directories found inside +explicitly given directories. +""" + +# The file structure is top-down except that the test program and its +# subroutine come last. + +__all__ = ["what","whathdr"] + +def what(filename): + """Guess the type of a sound file""" + res = whathdr(filename) + return res + + +def whathdr(filename): + """Recognize sound headers""" + f = open(filename, 'rb') + h = f.read(512) + for tf in tests: + res = tf(h, f) + if res: + return res + return None + + +#-----------------------------------# +# Subroutines per sound header type # +#-----------------------------------# + +tests = [] + +def test_aifc(h, f): + import aifc + if h[:4] != 'FORM': + return None + if h[8:12] == 'AIFC': + fmt = 'aifc' + elif h[8:12] == 'AIFF': + fmt = 'aiff' + else: + return None + f.seek(0) + try: + a = aifc.openfp(f, 'r') + except (EOFError, aifc.Error): + return None + return (fmt, a.getframerate(), a.getnchannels(), \ + a.getnframes(), 8*a.getsampwidth()) + +tests.append(test_aifc) + + +def test_au(h, f): + if h[:4] == '.snd': + f = get_long_be + elif h[:4] in ('\0ds.', 'dns.'): + f = get_long_le + else: + return None + type = 'au' + hdr_size = f(h[4:8]) + data_size = f(h[8:12]) + encoding = f(h[12:16]) + rate = f(h[16:20]) + nchannels = f(h[20:24]) + sample_size = 1 # default + if encoding == 1: + sample_bits = 'U' + elif encoding == 2: + sample_bits = 8 + elif encoding == 3: + sample_bits = 16 + sample_size = 2 + else: + sample_bits = '?' + frame_size = sample_size * nchannels + return type, rate, nchannels, data_size//frame_size, sample_bits + +tests.append(test_au) + + +def test_hcom(h, f): + if h[65:69] != 'FSSD' or h[128:132] != 'HCOM': + return None + divisor = get_long_be(h[128+16:128+20]) + return 'hcom', 22050//divisor, 1, -1, 8 + +tests.append(test_hcom) + + +def test_voc(h, f): + if h[:20] != 'Creative Voice File\032': + return None + sbseek = get_short_le(h[20:22]) + rate = 0 + if 0 <= sbseek < 500 and h[sbseek] == '\1': + ratecode = ord(h[sbseek+4]) + rate = int(1000000.0 / (256 - ratecode)) + return 'voc', rate, 1, -1, 8 + +tests.append(test_voc) + + +def test_wav(h, f): + # 'RIFF' <len> 'WAVE' 'fmt ' <len> + if h[:4] != 'RIFF' or h[8:12] != 'WAVE' or h[12:16] != 'fmt ': + return None + style = get_short_le(h[20:22]) + nchannels = get_short_le(h[22:24]) + rate = get_long_le(h[24:28]) + sample_bits = get_short_le(h[34:36]) + return 'wav', rate, nchannels, -1, sample_bits + +tests.append(test_wav) + + +def test_8svx(h, f): + if h[:4] != 'FORM' or h[8:12] != '8SVX': + return None + # Should decode it to get #channels -- assume always 1 + return '8svx', 0, 1, 0, 8 + +tests.append(test_8svx) + + +def test_sndt(h, f): + if h[:5] == 'SOUND': + nsamples = get_long_le(h[8:12]) + rate = get_short_le(h[20:22]) + return 'sndt', rate, 1, nsamples, 8 + +tests.append(test_sndt) + + +def test_sndr(h, f): + if h[:2] == '\0\0': + rate = get_short_le(h[2:4]) + if 4000 <= rate <= 25000: + return 'sndr', rate, 1, -1, 8 + +tests.append(test_sndr) + + +#---------------------------------------------# +# Subroutines to extract numbers from strings # +#---------------------------------------------# + +def get_long_be(s): + return (ord(s[0])<<24) | (ord(s[1])<<16) | (ord(s[2])<<8) | ord(s[3]) + +def get_long_le(s): + return (ord(s[3])<<24) | (ord(s[2])<<16) | (ord(s[1])<<8) | ord(s[0]) + +def get_short_be(s): + return (ord(s[0])<<8) | ord(s[1]) + +def get_short_le(s): + return (ord(s[1])<<8) | ord(s[0]) + + +#--------------------# +# Small test program # +#--------------------# + +def test(): + import sys + recursive = 0 + if sys.argv[1:] and sys.argv[1] == '-r': + del sys.argv[1:2] + recursive = 1 + try: + if sys.argv[1:]: + testall(sys.argv[1:], recursive, 1) + else: + testall(['.'], recursive, 1) + except KeyboardInterrupt: + sys.stderr.write('\n[Interrupted]\n') + sys.exit(1) + +def testall(list, recursive, toplevel): + import sys + import os + for filename in list: + if os.path.isdir(filename): + print filename + '/:', + if recursive or toplevel: + print 'recursing down:' + import glob + names = glob.glob(os.path.join(filename, '*')) + testall(names, recursive, 0) + else: + print '*** directory (use -r) ***' + else: + print filename + ':', + sys.stdout.flush() + try: + print what(filename) + except IOError: + print '*** not found ***' + +if __name__ == '__main__': + test() |