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| # | |
| # The Python Imaging Library. | |
| # $Id$ | |
| # | |
| # MPEG file handling | |
| # | |
| # History: | |
| # 95-09-09 fl Created | |
| # | |
| # Copyright (c) Secret Labs AB 1997. | |
| # Copyright (c) Fredrik Lundh 1995. | |
| # | |
| # See the README file for information on usage and redistribution. | |
| # | |
| from __future__ import annotations | |
| from . import Image, ImageFile | |
| from ._binary import i8 | |
| from ._typing import SupportsRead | |
| # | |
| # Bitstream parser | |
| class BitStream: | |
| def __init__(self, fp: SupportsRead[bytes]) -> None: | |
| self.fp = fp | |
| self.bits = 0 | |
| self.bitbuffer = 0 | |
| def next(self) -> int: | |
| return i8(self.fp.read(1)) | |
| def peek(self, bits: int) -> int: | |
| while self.bits < bits: | |
| c = self.next() | |
| if c < 0: | |
| self.bits = 0 | |
| continue | |
| self.bitbuffer = (self.bitbuffer << 8) + c | |
| self.bits += 8 | |
| return self.bitbuffer >> (self.bits - bits) & (1 << bits) - 1 | |
| def skip(self, bits: int) -> None: | |
| while self.bits < bits: | |
| self.bitbuffer = (self.bitbuffer << 8) + i8(self.fp.read(1)) | |
| self.bits += 8 | |
| self.bits = self.bits - bits | |
| def read(self, bits: int) -> int: | |
| v = self.peek(bits) | |
| self.bits = self.bits - bits | |
| return v | |
| def _accept(prefix: bytes) -> bool: | |
| return prefix[:4] == b"\x00\x00\x01\xb3" | |
| ## | |
| # Image plugin for MPEG streams. This plugin can identify a stream, | |
| # but it cannot read it. | |
| class MpegImageFile(ImageFile.ImageFile): | |
| format = "MPEG" | |
| format_description = "MPEG" | |
| def _open(self) -> None: | |
| assert self.fp is not None | |
| s = BitStream(self.fp) | |
| if s.read(32) != 0x1B3: | |
| msg = "not an MPEG file" | |
| raise SyntaxError(msg) | |
| self._mode = "RGB" | |
| self._size = s.read(12), s.read(12) | |
| # -------------------------------------------------------------------- | |
| # Registry stuff | |
| Image.register_open(MpegImageFile.format, MpegImageFile, _accept) | |
| Image.register_extensions(MpegImageFile.format, [".mpg", ".mpeg"]) | |
| Image.register_mime(MpegImageFile.format, "video/mpeg") | |