kc3-lang/angle/scripts/bmp_to_nv12.py

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• Hash : d7d42395
  Author :
  Date : 2019-05-06T13:15:35
  

  Format all of ANGLE's python code.
  
  BUG=angleproject:3421
  
  Change-Id: I1d7282ac513c046de5d8ed87f7789290780d30a6
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1595440
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Commit-Queue: Geoff Lang <geofflang@chromium.org>
  

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• scripts/bmp_to_nv12.py

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

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