This page hosts a formal specification of Microsoft AVI file using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for Python generated by Kaitai Struct depends on the Python runtime library. You have to install it before you can parse data.
The Python runtime library can be installed from PyPI:
python3 -m pip install kaitaistructParse a local file and get structure in memory:
data = Avi.from_file("path/to/local/file.avi")
Or parse structure from a bytes:
from kaitaistruct import KaitaiStream, BytesIO
raw = b"\x00\x01\x02..."
data = Avi(KaitaiStream(BytesIO(raw)))
After that, one can get various attributes from the structure by invoking getter methods like:
data.magic1 # => get magic1
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO
from enum import Enum
if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 9):
raise Exception("Incompatible Kaitai Struct Python API: 0.9 or later is required, but you have %s" % (kaitaistruct.__version__))
class Avi(KaitaiStruct):
"""
.. seealso::
Source - https://learn.microsoft.com/en-us/previous-versions/ms779636(v=vs.85)
"""
class ChunkType(Enum):
idx1 = 829973609
junk = 1263424842
info = 1330007625
isft = 1413894985
list = 1414744396
strf = 1718776947
avih = 1751742049
strh = 1752331379
movi = 1769369453
hdrl = 1819436136
strl = 1819440243
class StreamType(Enum):
mids = 1935960429
vids = 1935960438
auds = 1935963489
txts = 1937012852
class HandlerType(Enum):
mp3 = 85
ac3 = 8192
dts = 8193
cvid = 1684633187
xvid = 1684633208
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.magic1 = self._io.read_bytes(4)
if not self.magic1 == b"\x52\x49\x46\x46":
raise kaitaistruct.ValidationNotEqualError(b"\x52\x49\x46\x46", self.magic1, self._io, u"/seq/0")
self.file_size = self._io.read_u4le()
self.magic2 = self._io.read_bytes(4)
if not self.magic2 == b"\x41\x56\x49\x20":
raise kaitaistruct.ValidationNotEqualError(b"\x41\x56\x49\x20", self.magic2, self._io, u"/seq/2")
self._raw_data = self._io.read_bytes((self.file_size - 4))
_io__raw_data = KaitaiStream(BytesIO(self._raw_data))
self.data = Avi.Blocks(_io__raw_data, self, self._root)
class ListBody(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.list_type = KaitaiStream.resolve_enum(Avi.ChunkType, self._io.read_u4le())
self.data = Avi.Blocks(self._io, self, self._root)
class Rect(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.left = self._io.read_s2le()
self.top = self._io.read_s2le()
self.right = self._io.read_s2le()
self.bottom = self._io.read_s2le()
class Blocks(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.entries = []
i = 0
while not self._io.is_eof():
self.entries.append(Avi.Block(self._io, self, self._root))
i += 1
class AvihBody(KaitaiStruct):
"""Main header of an AVI file, defined as AVIMAINHEADER structure.
.. seealso::
Source - https://learn.microsoft.com/en-us/previous-versions/ms779632(v=vs.85)
"""
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.micro_sec_per_frame = self._io.read_u4le()
self.max_bytes_per_sec = self._io.read_u4le()
self.padding_granularity = self._io.read_u4le()
self.flags = self._io.read_u4le()
self.total_frames = self._io.read_u4le()
self.initial_frames = self._io.read_u4le()
self.streams = self._io.read_u4le()
self.suggested_buffer_size = self._io.read_u4le()
self.width = self._io.read_u4le()
self.height = self._io.read_u4le()
self.reserved = self._io.read_bytes(16)
class Block(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.four_cc = KaitaiStream.resolve_enum(Avi.ChunkType, self._io.read_u4le())
self.block_size = self._io.read_u4le()
_on = self.four_cc
if _on == Avi.ChunkType.list:
self._raw_data = self._io.read_bytes(self.block_size)
_io__raw_data = KaitaiStream(BytesIO(self._raw_data))
self.data = Avi.ListBody(_io__raw_data, self, self._root)
elif _on == Avi.ChunkType.avih:
self._raw_data = self._io.read_bytes(self.block_size)
_io__raw_data = KaitaiStream(BytesIO(self._raw_data))
self.data = Avi.AvihBody(_io__raw_data, self, self._root)
elif _on == Avi.ChunkType.strh:
self._raw_data = self._io.read_bytes(self.block_size)
_io__raw_data = KaitaiStream(BytesIO(self._raw_data))
self.data = Avi.StrhBody(_io__raw_data, self, self._root)
else:
self.data = self._io.read_bytes(self.block_size)
class StrhBody(KaitaiStruct):
"""Stream header (one header per stream), defined as AVISTREAMHEADER structure.
.. seealso::
Source - https://learn.microsoft.com/en-us/previous-versions/ms779638(v=vs.85)
"""
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.fcc_type = KaitaiStream.resolve_enum(Avi.StreamType, self._io.read_u4le())
self.fcc_handler = KaitaiStream.resolve_enum(Avi.HandlerType, self._io.read_u4le())
self.flags = self._io.read_u4le()
self.priority = self._io.read_u2le()
self.language = self._io.read_u2le()
self.initial_frames = self._io.read_u4le()
self.scale = self._io.read_u4le()
self.rate = self._io.read_u4le()
self.start = self._io.read_u4le()
self.length = self._io.read_u4le()
self.suggested_buffer_size = self._io.read_u4le()
self.quality = self._io.read_u4le()
self.sample_size = self._io.read_u4le()
self.frame = Avi.Rect(self._io, self, self._root)
class StrfBody(KaitaiStruct):
"""Stream format description."""
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
pass