def reread_f(size):
global F, f
pos = f.tell()
f.seek(F.offset)
if DEBUG: print "reread_f: now at", f.tell()
F_offset = F.offset
F_file = F.file
F = StringIO(f.read(F.len + size + 10))
F.file = F_file
F.offset = F_offset
f.seek(pos)
def mp3format(file, warn=1, max_skip=100000, offset=0):
global F, f, xing, id3v2, warnings, start_offset
warnings = warn
start_offset = offset
f = xing = id3v2 = None
if DEBUG:
print "examining", file, "warnings=%i" % warnings, "offset=%i" % start_offset, "max_skip=%i" % max_skip
# XXX we're using StringIO because it's faster - transitionally.
if type(file) == types.StringType:
f = open(file, "r")
elif hasattr(file, 'seek'):
f = file
else:
print "unknown object:", file
return None
f.seek(start_offset)
search_in = f.read(max_skip)
F = StringIO(search_in)
F.file = file
f.seek(start_offset)
F.offset = start_offset
x = syncronize(what=4)
if not x:
if warnings:
print "Warning: no MP3 header found in the first", F.tell(
), "bytes of file\n : \"" + file + "\"."
return {}
# we're quite sure we have a valid header now
if warnings > 1:
print "Warning: MP3 header found at offset", f.tell() - 4
# fill in convenience stuff
x = extend_frameinfo(x)
# the xing header is normally embedded in the first valid frame
# but sometimes it appears earlier, I don't know why. Use the 1st.
if not xing:
find_xing(x['framesize'])
if xing:
x.update(xing)
if x.has_key('x_frames'):
x['length_in_samples'] = x['x_frames'] * x['samples_per_frame']
x['length'] = float(x['length_in_samples']) / x['sfreq']
# should use the real file size instead of x_bytes.
if x.has_key("x_bytes"):
x['bitrate'] = int((x['x_bytes'] * 8.0 / x['length']) / 100 +
0.5)
x['bitrate'] = x['bitrate'] / 10.0
else:
print "strange xing=" + ` xing `
else:
x['length'] = stat(file)[ST_SIZE] * 8.0 / (x['bitrate'] * 1000)
if id3v2:
x['id3v2'] = id3v2
if DEBUG > 1: print x
return x
