зеркало из https://github.com/AvaloniaUI/angle.git
90 строки
3.0 KiB
Python
Executable File
90 строки
3.0 KiB
Python
Executable File
#!/usr/bin/python2
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#
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# Copyright 2016 The ANGLE Project Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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#
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# bmp_to_nv12.py:
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# Script to convert a simple BMP file to an NV12 format. Used to create
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# test images for the NV12 texture stream end to end tests
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import sys
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import struct
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if len(sys.argv) != 4:
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print("Usage: bmp_to_nv12.py input output prefix")
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exit(0)
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bmp_file = open(sys.argv[1], "rb")
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magic = bmp_file.read(2)
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if (magic != "BM"):
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print("Invalid BMP magic")
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exit(1)
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file_size, = struct.unpack("I", bmp_file.read(4))
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# eat reserved bytes
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bmp_file.read(4)
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offset, = struct.unpack("I", bmp_file.read(4))
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headersize, = struct.unpack("I", bmp_file.read(4))
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width, = struct.unpack("i", bmp_file.read(4))
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height, = struct.unpack("i", bmp_file.read(4))
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planes, = struct.unpack("H", bmp_file.read(2))
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bpp, = struct.unpack("H", bmp_file.read(2))
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compression, = struct.unpack("i", bmp_file.read(4))
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image_size, = struct.unpack("i", bmp_file.read(4))
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if (bpp != 24 or compression != 0):
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print("Unsupported BMP file")
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bmp_file.close()
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exit(1)
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bmp_file.seek(offset, 0)
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pixels = bmp_file.read(width * height * 3)
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bmp_file.close()
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# convert to YUV 4:4:4
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converted_pixels = bytearray(pixels)
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for i in range(0, width * height):
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R, = struct.unpack("B", pixels[i * 3 + 2])
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G, = struct.unpack("B", pixels[i * 3 + 1])
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B, = struct.unpack("B", pixels[i * 3])
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converted_pixels[i * 3] = ((66 * R + 129 * G + 25 * B + 128) >> 8) + 16
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converted_pixels[i * 3 + 1] = ((-38 * R - 74 * G + 112 * B + 128) >> 8) + 128
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converted_pixels[i * 3 + 2] = ((112 * R - 94 * G - 18 * B + 128) >> 8) + 128
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# downsample to packed UV buffer
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uv_buffer = bytearray(width * height / 2)
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for i in range(0, width * height / 2, 2):
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U1 = converted_pixels[((((i / width) * 2) * width) + (i % width)) * 3 + 1]
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U2 = converted_pixels[((((i / width) * 2) * width) + width + (i % width)) * 3 + 1]
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V1 = converted_pixels[((((i / width) * 2) * width) + (i % width)) * 3 + 2]
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V2 = converted_pixels[((((i / width) * 2) * width) + width + (i % width)) * 3 + 2]
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uv_buffer[i] = (U1 + U2) / 2
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uv_buffer[i + 1] = (V1 + V2) / 2
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# extract the Y buffer
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y_buffer = bytearray(width * height)
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for i in range(0, width * height):
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y_buffer[i] = converted_pixels[i * 3]
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# write out the file as a C header
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nv12_file = open(sys.argv[2], "w")
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nv12_file.write("// Automatically generated from " + sys.argv[1] + "\n")
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nv12_file.write("static const size_t " + sys.argv[3] + "_width = " + str(width) + ";\n")
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nv12_file.write("static const size_t " + sys.argv[3] + "_height = " + str(height) + ";\n")
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nv12_file.write("static const unsigned char " + sys.argv[3] + "_data[] = \n{")
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for i in range(0, width * height):
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if (i % 16) == 0:
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nv12_file.write("\n ")
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nv12_file.write(str(y_buffer[i]) + ",")
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for i in range(0, width * height / 2):
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if (i % 16) == 0:
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nv12_file.write("\n ")
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nv12_file.write(str(uv_buffer[i]) + ",")
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nv12_file.write("\n};")
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nv12_file.close()
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