从视频/图像中提取元数据 [英] Extract metadata from a Video/Image

问题描述

我从 IP 摄像机获取 MJPEG 流，我正在查看并保存在我的计算机上.可以在here.答案解释了如何从流中提取图像并保存.

I am getting an MJPEG stream from an IP Camera which I am viewing and saving on my computer. The code of how I am doing it can be found here. The answer explains how to extract the images from the stream and save them.

为了提取图像，我使用答案中列出的方法并保存它，我只是使用 OpenCV 将图像放入 avi 容器中.代码如下.

For extracting the images I am using the method listed in the answer and for saving it I am simply putting the images in an avi container using OpenCV. The code is given below.

writer=cv.CreateVideoWriter("video1.avi", cv.CV_FOURCC('X', '2', '6', '4'), fps, (320,240))
cv_image = cv2.imdecode(np.fromstring(jpg, dtype=np.uint8),cv2.CV_LOAD_IMAGE_COLOR)bitmap=cv.CreateImageHeader((cv_image.shape[1], cv_image.shape[0]), cv.IPL_DEPTH_8U, 3)
cv.SetData(bitmap, cv_image.tostring(), cv_image.dtype.itemsize * 3 * cv_image.shape[1])
cv.WriteFrame(writer, bitmap)

这里的位图是我正在显示并放入 avi 容器中的图像.

Here bitmap is the image that I am displaying and putting in the avi container.

由于图像来自 IP 摄像机，因此它必须具有一些元数据，例如摄像机插入的时间戳.

Since the image is from an IP Camera it must have some metyadata like a time stamp which the camera inserts.

问题:如何提取元数据?

我想到了两种方法来做到这一点:

I have thought of 2 ways to do this:

1. 从视频中提取帧，然后访问它们以访问时间戳.
2. 从视频本身提取时间戳.

我该如何继续?我使用哪种方法?我正在使用 Python 和 Opencv，并且正在使用 Windows 7.

How do I proceed? Which method do I use? I am using Python and Opencv and am working on Windows 7.

我还阅读了this 喜欢与我正在尝试做的事情有关.它没有解决我的问题.

I also read this like related to what I am trying to do. It did not solve my problem.

推荐答案

如果有任何附加到(单个图像)文件的元数据，不幸的是，opencv 将丢弃它.

if there is any metadata attached to the (single image) file, opencv will discard it, unfortunately.

此外，mjpeg 协议本身没有任何时间戳(它只是一个与图像交错的 http-multi-part-form [非常类似于电子邮件附件]，所以内容类型和内容长度就是你的全部)到达那里 [并且仅当您使用 http1.1 时]).

also, the mjpeg protocol does not have any timestamps on its own (it's just a http-multi-part-form interleaved with images [pretty similar to email-attachments], so content-type and content-length is all you get there [and that only if you're using http1.1]).

对于否定的答案很抱歉，但为此您必须研究除 opencv 之外的图像处理工具.

sorry for the negative answer, but you'll have to look into image-processing tools apart from opencv for this.

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