用opencv保存mp4

Question

Why No video saved?

    self.writer = cv.CreateVideoWriter("test1.mp4", cv2.cv.CV_FOURCC('M', 'J', 'P', 'G'), fps, frame_size, is_color )

    self.writer = cv.CreateVideoWriter("tsest3.mp4",cv.CV_FOURCC(*'H264'), fps, (320, 240), is_color )
    self.writer = cv.CreateVideoWriter("test4.mpg", cv.CV_FOURCC('P', 'I', 'M', '1'), fps, (320, 240), is_color )

I used WriteFrame too but still no file created or the size is 0kb.

Answer 1

According to the OpenCV 2.4.11.0 documentation -

However, OpenCV is mainly a computer vision library, not a video stream, codec and write one. Therefore, the developers tried to keep this part as simple as possible. Due to this OpenCV for video containers supports only the avi extension, its first version. A direct limitation of this is that you cannot save a video file larger than 2 GB.

Workaround-

As an alternative, create the video track with OpenCV and expand it with sound tracks or convert it to other formats by using video manipulation programs such as VirtualDub or AviSynth.

Do read the complete section describing the structure of video files. Also have a look at https://stackoverflow.com/a/29746666/3681882