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import sys, struct, md5
def hash(data):
    if data[4:12] == 'ftypM4A ':
        return hash_m4a(data)
    else:
        return hash_default(data)
def hash_m4a(data):
    subatoms = [['moov'], ['trak', 'udta'], ['mdia', 'meta'], ['minf', 'ilst'], ['stbl'], [], []]
    atoms_to_hash = ['mdat', 'oboe', 'apID', 'atID']
    hash = md5.new()
    def parse_data(data, depth):
        loc = 0
        while loc < len(data):
            size = struct.unpack('>L', data[loc:loc+4])[0]
            if size == 0:
                atom = data[loc+4:loc+8]
                subdata = data[loc+8:]
                break
            atom = data[loc+4:loc+8]
            subdata = data[loc+8:loc+size]
            if atom in subatoms[depth]:
                if atom == 'meta':
                    parse_data(subdata[4:], depth+1)
                else:
                    parse_data(subdata, depth + 1)
            if atom in atoms_to_hash:
                hash.update(data[loc+4:loc+size])
            loc += size
    parse_data(data, 0)
    return hash.hexdigest()
f = file(sys.argv[1], 'rb')
data = f.read()
print hash(data)