YUV格式转换
NV21 to RGB888
- 各种YUV格式详解: https://www.jianshu.com/p/e67f79f10c65
- NV21是420sp的一种，先V后U，YYYYYYYYVUVU
python的直白版本
性能很差，转换1280*720的图片要1.2s
def clamp2byte(v):
if v < 0:
return chr(0)
elif v > 255:
return chr(255)
else:
return chr(int(v))
def convert(src, width, height):
dst = ''
for y in range(height):
for x in range(width):
Y = src[y * width + x]
V = src[width * height + (y / 2) * width + (x / 2) * 2]
U = src[width * height + (y / 2) * width + (x / 2) * 2 + 1]
Y = ord(Y)
U = ord(U)
V = ord(V)
R = Y + 1.402 * (V - 128);
G = Y - 0.34413 * (U - 128) - 0.71414 * (V - 128);
B = Y + 1.772 * (U - 128)
R = clamp2byte(R)
G = clamp2byte(G)
B = clamp2byte(B)
dst += R
dst += G
dst += B
return dst
