97 lines
2.9 KiB
Python
97 lines
2.9 KiB
Python
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from enum import IntEnum
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class DscCompressionInfo:
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"""
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Class contains information about DSC compression used on frame.
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"""
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class DscColorFormat(IntEnum):
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"""
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Contains values of possible color format.
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"""
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CF_NONE = -1
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CF_RGB = 0
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CF_YCbCr_422 = 1
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CF_YCbCr_444 = 2
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CF_YCbCr_420 = 3
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CF_Simple_422 = 4
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def __init__(self):
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self.color_format = DscCompressionInfo.DscColorFormat.CF_NONE
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self.bpp = 0
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self.is_block_prediction_enabled = False
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self.h_slice_size = 0
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self.v_slice_size = 0
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self.buffer_bit_depth = 0
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self.version = (0, 0)
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self.is_simple_as_444 = False
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def is_valid(self) -> bool:
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"""
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Return state of the video frame and check color_format, bpp, h and v slice_size and DSC version.
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If everything ok, return True, otherwise - False.
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Returns:
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object of `bool` type.
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"""
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return self.color_format is not None and\
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self.bpp > 0 and\
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self.h_slice_size > 0 and\
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self.v_slice_size > 0 and\
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self.version in [(1, 2), (1, 1)]
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def create_from_pps(pps_bytearray: bytearray) -> DscCompressionInfo:
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"""
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Fill structure 'DscCompressionInfo' from PPS header of the DSC image.
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Returns:
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object of `DscCompressionInfo` type.
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"""
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if b'DSCF' not in pps_bytearray:
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if len(pps_bytearray) < 128:
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raise ValueError("Incorrect PPS size!")
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pps = pps_bytearray
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else:
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if len(pps_bytearray) < 132:
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raise ValueError("Incorrect PPS size!")
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pps = pps_bytearray[4:]
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is_yuv = ((pps[4] >> 4) & 1) == 0
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is_simple422 = ((pps[4] >> 3) & 1) == 1
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is_native422 = (pps[88] & 1) == 1
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is_native420 = ((pps[88] >> 1) & 1) == 1
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width = (pps[8] << 8) | pps[9]
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height = (pps[6] << 8) | pps[7]
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slice_height = (pps[10] << 8) | pps[11]
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slice_width = (pps[12] << 8) | pps[13]
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info = DscCompressionInfo()
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info.version = (pps[0] >> 4 & 0xf, pps[0] & 0xf)
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info.buffer_bit_depth = pps[3] & 0xf
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info.is_block_prediction_enabled = bool(pps[4] >> 5 & 0x1)
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info.h_slice_size = int(width / slice_width)
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info.v_slice_size = int(height / slice_height)
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if is_native422 or is_native420:
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info.bpp = int(pps[4] & 0x3 << 8 | pps[5]) / 2
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else:
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info.bpp = int(pps[4] & 0x3 << 8 | pps[5])
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if is_yuv:
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if is_simple422:
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info.color_format = DscCompressionInfo.DscColorFormat.CF_Simple_422
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elif is_native422:
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info.color_format = DscCompressionInfo.DscColorFormat.CF_YCbCr_422
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elif is_native420:
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info.color_format = DscCompressionInfo.DscColorFormat.CF_YCbCr_420
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else:
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info.color_format = DscCompressionInfo.DscColorFormat.CF_YCbCr_444
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else:
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info.color_format = DscCompressionInfo.DscColorFormat.CF_RGB
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return info
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