def decode(self, file_strm):
if file_strm is None:
print "file_strm is None"
return file_strm
file_strm = FullBox.decode(self, file_strm)
if self.version == 1:
self.creation_time = file_strm.ReadUInt64()
self.creation_time -= UTC_MP4_INTERVAL
self.offset += UInt64ByteLen
if self.creation_time > 0:
self.creation_time_fmt = Util.datetime_format(
self.creation_time)
self.modification_time = file_strm.ReadUInt64()
self.modification_time -= UTC_MP4_INTERVAL
self.offset += UInt64ByteLen
if self.modification_time > 0:
self.modification_time_fmt = Util.datetime_format(
self.modification_time)
self.timescale = file_strm.read_uint32()
self.offset += UInt32ByteLen
self.duration = file_strm.ReadUInt64()
self.offset += UInt64ByteLen
else:
self.creation_time = file_strm.read_uint32()
self.creation_time -= UTC_MP4_INTERVAL
self.offset += UInt32ByteLen
if self.creation_time > 0:
self.creation_time_fmt = Util.datetime_format(
self.creation_time)
self.modification_time = file_strm.read_uint32()
self.modification_time -= UTC_MP4_INTERVAL
self.offset += UInt32ByteLen
if self.modification_time > 0:
self.modification_time_fmt = Util.datetime_format(
self.modification_time)
self.timescale = file_strm.read_uint32()
self.offset += UInt32ByteLen
self.duration = file_strm.read_uint32()
self.offset += UInt32ByteLen
"""
ISO Language Codes
Because the language codes specified by ISO 639-2/T are three
characters long, they must be packed to fit into a 16-bit field.
The packing algorithm must map each of the three characters, which
are always lowercase, into a 5-bit integer and then concatenate
these integers into the least significant 15 bits of a 16-bit
integer, leaving the 16-bit integer’s most significant bit set
to zero.
One algorithm for performing this packing is to treat each ISO
character as a 16-bit integer. Subtract 0x60 from the first
character and multiply by 2^10 (0x400), subtract 0x60 from the
second character and multiply by 2^5 (0x20), subtract 0x60 from
the third character, and add the three 16-bit values. This will
result in a single 16-bit value with the three codes correctly
packed into the 15 least significant bits and the most significant
bit set to zero.
Example: The ISO language code 'jpn' consists of the three hexadecimal
values 0x6A, 0x70, 0x6E. Subtracting 0x60 from each value yields the
values 0xA, 0x10, 0xE, as shown in Table 5-2.
Table 5-2 5-bit values of UTF-8 characters
Character UTF-8 code 5-bit value Shifted value
j 0x6A 0xA (01010) 0x2800 (01010..........)
p 0x70 0x10 (10000) 0x200 (.....10000.....)
n 0x6E 0xE (01110) 0xE (..........01110)
The first value is shifted 10 bits to the left (multiplied by 0x400)
and the second value is shifted 5 bits to the left (multiplied by 0x20).
This yields the values 0x2800, 0x200, 0xE. When added, this results in
the 16-bit packed language code value of 0x2A0E
"""
self.language_code = file_strm.read_uint16()
self.offset += UInt16ByteLen
self.pad = self.language_code >> 15 & 0x01
for i in range(len(self.language)):
lang_ = ((self.language_code >> ((2 - i) * 5)) & 0x1F) + 0x60
self.language[i] = chr(lang_)
self.pre_defined = file_strm.read_uint16()
self.offset += UInt16ByteLen
tmp_size = self.offset - self.box_offset
if tmp_size != self.Size():
file_strm.seek(self.Size() - tmp_size, os.SEEK_CUR)
return file_strm
def decode(self, file_strm):
if file_strm is None:
print "file_strm is None"
return file_strm
file_strm = FullBox.decode(self, file_strm)
if self.version == 1:
self.creation_time = file_strm.read_uint64()
self.creation_time -= UTC_MP4_INTERVAL
self.offset += UInt64ByteLen
if self.creation_time > 0:
self.creation_time_fmt = Util.datetime_format(
self.creation_time)
self.modification_time = file_strm.read_uint64()
self.modification_time -= UTC_MP4_INTERVAL
self.offset += UInt64ByteLen
if self.modification_time > 0:
self.modification_time_fmt = Util.datetime_format(
self.modification_time)
self.timescale = file_strm.read_uint32()
self.offset += UInt32ByteLen
self.duration = file_strm.read_uint64()
self.offset += UInt64ByteLen
else:
self.creation_time = file_strm.read_uint32()
self.creation_time -= UTC_MP4_INTERVAL
self.offset += UInt32ByteLen
if self.creation_time > 0:
self.creation_time_fmt = Util.datetime_format(
self.creation_time)
self.modification_time = file_strm.read_uint32()
self.modification_time -= UTC_MP4_INTERVAL
self.offset += UInt32ByteLen
if self.modification_time > 0:
self.modification_time_fmt = Util.datetime_format(
self.modification_time)
self.timescale = file_strm.read_uint32()
self.offset += UInt32ByteLen
self.duration = file_strm.read_uint32()
self.offset += UInt32ByteLen
self.rate = file_strm.read_uint32()
self.offset += UInt32ByteLen
self.rate_fmt = "%d.%d" % (self.rate >> 16, self.rate & 0x0000FFFF)
self.volume = file_strm.read_uint16()
self.offset += UInt16ByteLen
self.volume_fmt = "%d.%d" % (self.volume >> 8, self.volume & 0x00FF)
self.reserved = file_strm.read_uint16()
self.offset += UInt16ByteLen
for idx in range(len(self.reserved1)):
reserved1_ = file_strm.read_uint32()
self.offset += UInt32ByteLen
self.reserved1[idx] = reserved1_
for idx in range(len(self.matrix)):
matrix_ = file_strm.read_uint32()
self.offset += UInt32ByteLen
self.matrix[idx] = matrix_
for idx in range(len(self.pre_defined)):
pre_defined_ = file_strm.read_uint32()
self.offset += UInt32ByteLen
self.pre_defined[idx] = pre_defined_
self.next_track_ID = file_strm.read_uint32()
self.offset += UInt32ByteLen
tmp_size = self.offset - self.box_offset
if tmp_size != self.Size():
file_strm.seek(self.Size() - tmp_size, os.SEEK_CUR)
return file_strm
