85 lines
2.0 KiB
Python
85 lines
2.0 KiB
Python
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#
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# The Python Imaging Library.
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# $Id$
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#
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# MPEG file handling
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#
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# History:
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# 95-09-09 fl Created
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#
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# Copyright (c) Secret Labs AB 1997.
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# Copyright (c) Fredrik Lundh 1995.
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#
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# See the README file for information on usage and redistribution.
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#
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from __future__ import annotations
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from . import Image, ImageFile
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from ._binary import i8
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from ._typing import SupportsRead
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#
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# Bitstream parser
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class BitStream:
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def __init__(self, fp: SupportsRead[bytes]) -> None:
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self.fp = fp
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self.bits = 0
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self.bitbuffer = 0
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def next(self) -> int:
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return i8(self.fp.read(1))
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def peek(self, bits: int) -> int:
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while self.bits < bits:
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c = self.next()
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if c < 0:
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self.bits = 0
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continue
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self.bitbuffer = (self.bitbuffer << 8) + c
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self.bits += 8
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return self.bitbuffer >> (self.bits - bits) & (1 << bits) - 1
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def skip(self, bits: int) -> None:
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while self.bits < bits:
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self.bitbuffer = (self.bitbuffer << 8) + i8(self.fp.read(1))
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self.bits += 8
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self.bits = self.bits - bits
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def read(self, bits: int) -> int:
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v = self.peek(bits)
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self.bits = self.bits - bits
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return v
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##
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# Image plugin for MPEG streams. This plugin can identify a stream,
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# but it cannot read it.
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class MpegImageFile(ImageFile.ImageFile):
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format = "MPEG"
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format_description = "MPEG"
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def _open(self) -> None:
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assert self.fp is not None
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s = BitStream(self.fp)
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if s.read(32) != 0x1B3:
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msg = "not an MPEG file"
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raise SyntaxError(msg)
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self._mode = "RGB"
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self._size = s.read(12), s.read(12)
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# --------------------------------------------------------------------
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# Registry stuff
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Image.register_open(MpegImageFile.format, MpegImageFile)
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Image.register_extensions(MpegImageFile.format, [".mpg", ".mpeg"])
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Image.register_mime(MpegImageFile.format, "video/mpeg")
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