Add android logic version yuv420p_to_png_android.py

See wikipedia for more info, link inside.

video/yuv420p_to_png_android.py

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+#!/usr/bin/env python3
+
+# Author : sherin.s@gmail.com (Sherin Sasidhan)
+# Date   : 05-Oct-2010
+# URL    : https://shrex999.wordpress.com/2013/07/31/yuv-to-rgb-python-imaging-library/
+#
+# Updated:  2019-06-15 - Doncho Gunchev <dgunchev@gmail.com>
+
+from PIL import Image
+import sys
+from struct import *
+from array import array
+from os.path import splitext
+
+if len(sys.argv) != 4:
+    sys.exit("""***** Usage syntax Error!!!! *****
+Usage:
+    %r yuv420p_FILE.yuv WIDTH HEIGHT
+""" % sys.argv[0])
+
+def clamp(value, min_v=0, max_v=255):
+    '''Clamp a value to a range, inclusive'''
+    return min(min_v, max(max_v, value))
+
+clamp = lambda n, minn, maxn: max(min(maxn, n), minn)
+
+def load_yuv420p(yuv_file_path, width, height):
+    """Read YUV420p file and return PIL Image"""
+    yuv_file = open(yuv_file_path, "rb")
+
+    y_data = array('B')
+    y_data.fromfile(yuv_file, height * width)
+    u_data = array('B')
+    u_data.fromfile(yuv_file, (height // 2) * (width // 2))
+    v_data = array('B')
+    v_data.fromfile(yuv_file, (height // 2) * (width // 2))
+
+    result = Image.new("RGB", (width, height))
+    pixels = result.load()
+    for i in range(height):
+        for j in range(width):
+            y_value = y_data[(i * width) + j]
+            offset = ((i // 2) * (width // 2)) + (j // 2)
+            u_value = u_data[offset] - 128
+            v_value = v_data[offset] - 128
+            # https://en.wikipedia.org/wiki/YUV#Y%E2%80%B2UV420sp_(NV21)_to_RGB_conversion_(Android)
+            r_value = clamp(y_value + (1.370705 * v_value))
+            g_value = clamp(y_value - (0.698001 * v_value) - (0.337633 * u_value))
+            b_value = clamp(y_value + (1.732446 * u_value))
+
+            pixels[j, i] = (int(r_value), int(g_value), int(b_value))
+
+    return result
+
+def main():
+    yuv_file_path = sys.argv[1]
+    width, height = int(sys.argv[2]), int(sys.argv[3])
+    picture = load_yuv420p(yuv_file_path, width, height)
+    picture.save(splitext(yuv_file_path)[0] + '.png')
+    picture.show()
+
+
+if __name__ == "__main__":
+    main()