<p>如果YUV标准与OpenCV <code>COLOR_YUV2BGR_I420</code>转换公式相匹配,则可以将帧作为一个块读取,并将其重塑为高度*1.5行应用转换</p>
<p>以下代码示例:</p>
<ul>
<li>以YUV420格式构建输入,并将其写入内存流(而不是fifo)</李>
<li>从流中读取帧并使用<code>COLOR_YUV2BGR_I420</code>将其转换为BGR。<br/>
颜色不正确</李>
<li>通过读取Y、U和V、调整U和V的大小并使用<code>COLOR_YCrCb2BGR</code>转换来重复该过程。<br/>
注意:OpenCV使用BGR颜色格式(非RGB)</李>
</ul>
<p>代码如下:</p>
<pre><code>import cv2
import numpy as np
import io
# Building the input:
###############################################################################
img = cv2.imread('GrandKingdom.jpg')
#yuv = cv2.cvtColor(img, cv2.COLOR_BGR2YUV)
#y, u, v = cv2.split(yuv)
# Convert BGR to YCrCb (YCrCb apply YCrCb JPEG (or YCC), "full range",
# where Y range is [0, 255], and U, V range is [0, 255] (this is the default JPEG format color space format).
yvu = cv2.cvtColor(img, cv2.COLOR_BGR2YCrCb)
y, v, u = cv2.split(yvu)
# Downsample U and V (apply 420 format).
u = cv2.resize(u, (u.shape[1]//2, u.shape[0]//2))
v = cv2.resize(v, (v.shape[1]//2, v.shape[0]//2))
# Open In-memory bytes streams (instead of using fifo)
f = io.BytesIO()
# Write Y, U and V to the "streams".
f.write(y.tobytes())
f.write(u.tobytes())
f.write(v.tobytes())
f.seek(0)
###############################################################################
# Read YUV420 (I420 planar format) and convert to BGR
###############################################################################
data = f.read(y.size*3//2) # Read one frame (number of bytes is width*height*1.5).
# Reshape data to numpy array with height*1.5 rows
yuv_data = np.frombuffer(data, np.uint8).reshape(y.shape[0]*3//2, y.shape[1])
# Convert YUV to BGR
bgr = cv2.cvtColor(yuv_data, cv2.COLOR_YUV2BGR_I420);
# How to How should I be placing the u and v channel information in all_yuv_data?
# -
# Example: place the channels one after the other (for a single frame)
f.seek(0)
y0 = f.read(y.size)
u0 = f.read(y.size//4)
v0 = f.read(y.size//4)
yuv_data = y0 + u0 + v0
yuv_data = np.frombuffer(yuv_data, np.uint8).reshape(y.shape[0]*3//2, y.shape[1])
bgr = cv2.cvtColor(yuv_data, cv2.COLOR_YUV2BGR_I420);
###############################################################################
# Display result:
cv2.imshow("bgr incorrect colors", bgr)
###############################################################################
f.seek(0)
y = np.frombuffer(f.read(y.size), dtype=np.uint8).reshape((y.shape[0], y.shape[1])) # Read Y color channel and reshape to height x width numpy array
u = np.frombuffer(f.read(y.size//4), dtype=np.uint8).reshape((y.shape[0]//2, y.shape[1]//2)) # Read U color channel and reshape to height x width numpy array
v = np.frombuffer(f.read(y.size//4), dtype=np.uint8).reshape((y.shape[0]//2, y.shape[1]//2)) # Read V color channel and reshape to height x width numpy array
# Resize u and v color channels to be the same size as y
u = cv2.resize(u, (y.shape[1], y.shape[0]))
v = cv2.resize(v, (y.shape[1], y.shape[0]))
yvu = cv2.merge((y, v, u)) # Stack planes to 3D matrix (use Y,V,U ordering)
bgr = cv2.cvtColor(yvu, cv2.COLOR_YCrCb2BGR)
###############################################################################
# Display result:
cv2.imshow("bgr", bgr)
cv2.waitKey(0)
cv2.destroyAllWindows()
</code></pre>
<hr/>
<p>结果:<br/>
<a href="https://i.stack.imgur.com/rJu7P.png" rel="noreferrer"><img src="https://i.stack.imgur.com/rJu7P.png" alt="enter image description here"/></a></p>