python - 你如何设置 cv.CreateVideoWriter 的帧大小

Question

如果我尝试:

writer = cv.CreateVideoWriter(file, -1,(int(800),int(600)), is_color=1)

-或-

writer = cv.CreateVideoWriter(file, -1,(800,600), is_color=1)

-或-

writer = cv.CreateVideoWriter(file, -1,(800.0,600.0), is_color=1)

我得到错误:

TypeError: a float is required

有了这个，我得到了进步:

writer = cv.CreateVideoWriter(file, -1, 25.0, (800,600), is_color=1)

error: Gstreamer Opencv backend doesn't support this codec acutally.

输入文件是.png，输出是.avi

Answer 1

您需要传递有效的 fourcc 和 fps:

fourcc = cv.CV_FOURCC('X','V','I','D')
fps = 25.0 # or 30.0 for a better quality stream
writer = cv.CreateVideoWriter(file, fourcc, 25.0, (800,600), is_color=1)

或者，您可以在 Python 中使用命名参数。这样不容易出错:

writer = cv.CreateVideoWriter(
    filename=file,
    fourcc=cv.CV_FOURCC('X','V','I','D'),
    fps=25.0,
    frame_size=(800,600),
    is_color=1)

fourcc 是目标 avi 中视频流编解码器的 32 位标识符。根据 cap_gstreamer.cpp 的 gstreamer 的可能值是:

cv.CV_FOURCC('H','F','Y','U') # HuffYUV
cv.CV_FOURCC('D','R','A','C') # BBC Dirac
cv.CV_FOURCC('X','V','I','D') # MPEG-4 Part 2
cv.CV_FOURCC('X','2','6','4') # MPEG-4 Part 10 (aka. H.264 or AVC)
cv.CV_FOURCC('M','P','1','V') # MPEG-1 video

我相信以上所有内容都可以放在 avi 容器中。