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Minor optimization in yuv420p_to_png.py

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Doncho N. Gunchev 2019-06-15 19:57:24 +03:00
parent f496c77b77
commit 4b1796a4c3
1 changed files with 11 additions and 13 deletions
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24
video/yuv420p_to_png.py
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@ -23,28 +23,26 @@ def load_yuv420p(yuv_file_path, width, height):
"""Read YUV420p file and return PIL Image""" """Read YUV420p file and return PIL Image"""
yuv_file = open(yuv_file_path, "rb") yuv_file = open(yuv_file_path, "rb")
y_data = array('B') y_data_size = height * width
y_data.fromfile(yuv_file, height * width) uv_data_size = y_data_size // 4
u_data = array('B') yuv_data = array('B')
u_data.fromfile(yuv_file, (height // 2) * (width // 2)) yuv_data.fromfile(yuv_file, y_data_size + 2 * uv_data_size)
v_data = array('B')
v_data.fromfile(yuv_file, (height // 2) * (width // 2))
result = Image.new("RGB", (width, height)) result = Image.new("RGB", (width, height))
pixels = result.load() pixels = result.load()
for i in range(height): for y in range(height):
for j in range(width): for x in range(width):
y_value = (y_data[(i * width) + j] - 16) * 1.164 y_value = (yuv_data[(y * width) + x] - 16) * 1.164
offset = ((i // 2) * (width // 2)) + (j // 2) offset = y_data_size + ((y // 2) * (width // 2)) + (x // 2)
u_value = u_data[offset] - 128 u_value = yuv_data[offset] - 128
v_value = v_data[offset] - 128 v_value = yuv_data[offset + uv_data_size] - 128
# B = 1.164(Y - 16) + 2.018(U - 128) # B = 1.164(Y - 16) + 2.018(U - 128)
# G = 1.164(Y - 16) - 0.813(V - 128) - 0.391(U - 128) # G = 1.164(Y - 16) - 0.813(V - 128) - 0.391(U - 128)
# R = 1.164(Y - 16) + 1.596(V - 128) # R = 1.164(Y - 16) + 1.596(V - 128)
b_value = y_value + 2.018 * u_value b_value = y_value + 2.018 * u_value
g_value = y_value - 0.813 * v_value - 0.391 * u_value g_value = y_value - 0.813 * v_value - 0.391 * u_value
r_value = y_value + 1.596 * v_value r_value = y_value + 1.596 * v_value
pixels[j, i] = (int(r_value), int(g_value), int(b_value)) pixels[x, y] = (int(r_value), int(g_value), int(b_value))
return result return result