def __read_offsets(self, filename):
fileobj = open(filename, 'rb')
atoms = Atoms(fileobj)
moov = atoms[b'moov']
samples = []
for atom in moov.findall(b'stco', True):
fileobj.seek(atom.offset + 12)
data = fileobj.read(atom.length - 12)
fmt = ">{}I".format(cdata.uint_be(data[:4]))
offsets = struct.unpack(fmt, data[4:])
for offset in offsets:
fileobj.seek(offset)
samples.append(fileobj.read(8))
for atom in moov.findall(b'co64', True):
fileobj.seek(atom.offset + 12)
data = fileobj.read(atom.length - 12)
fmt = ">{}Q".format(cdata.uint_be(data[:4]))
offsets = struct.unpack(fmt, data[4:])
for offset in offsets:
fileobj.seek(offset)
samples.append(fileobj.read(8))
try:
for atom in atoms[b"moof"].findall(b'tfhd', True):
data = fileobj.read(atom.length - 9)
flags = cdata.uint_be(b"\x00" + data[:3])
if flags & 1:
offset = cdata.ulonglong_be(data[7:15])
fileobj.seek(offset)
samples.append(fileobj.read(8))
except KeyError:
pass
fileobj.close()
return samples
def __update_tfhd(self, fileobj, atom, delta, offset):
if atom.offset > offset:
atom.offset += delta
fileobj.seek(atom.offset + 9)
data = fileobj.read(atom.length - 9)
flags = cdata.uint_be(b"\x00" + data[:3])
if flags & 1:
o = cdata.ulonglong_be(data[7:15])
if o > offset:
o += delta
fileobj.seek(atom.offset + 16)
fileobj.write(cdata.to_ulonglong_be(o))
def __update_tfhd(self, fileobj, atom, delta, offset):
if atom.offset > offset:
atom.offset += delta
fileobj.seek(atom.offset + 9)
data = fileobj.read(atom.length - 9)
flags = cdata.uint_be(b"\x00" + data[:3])
if flags & 1:
o = cdata.ulonglong_be(data[7:15])
if o > offset:
o += delta
fileobj.seek(atom.offset + 16)
fileobj.write(cdata.to_ulonglong_be(o))
def __update_parents(self, fileobj, path, delta):
"""Update all parent atoms with the new size."""
for atom in path:
fileobj.seek(atom.offset)
size = cdata.uint_be(fileobj.read(4))
if size == 1: # 64bit
# skip name (4B) and read size (8B)
size = cdata.ulonglong_be(fileobj.read(12)[4:])
fileobj.seek(atom.offset + 8)
fileobj.write(cdata.to_ulonglong_be(size + delta))
else: # 32bit
fileobj.seek(atom.offset)
fileobj.write(cdata.to_uint_be(size + delta))
def __update_parents(self, fileobj, path, delta):
"""Update all parent atoms with the new size."""
for atom in path:
fileobj.seek(atom.offset)
size = cdata.uint_be(fileobj.read(4))
if size == 1: # 64bit
# skip name (4B) and read size (8B)
size = cdata.ulonglong_be(fileobj.read(12)[4:])
fileobj.seek(atom.offset + 8)
fileobj.write(cdata.to_ulonglong_be(size + delta))
else: # 32bit
fileobj.seek(atom.offset)
fileobj.write(cdata.to_uint_be(size + delta))
