重写视频后像素值发生了变化(pixel value changed after rewrite the video)

重写视频后像素值发生了变化(pixel value changed after rewrite the video)

我有灰度（X射线）的视频......问题是当我读取和写入视频时像素值发生变化！ 我将像素值打印为灰色和BGR，我在所有这些中都得到了值......我读了视频，然后用openCV写了它，然后我重新打印像素值，我看到像素值不同！

我在MAC 10.6.8上使用openCV 2.4.3和FFMPEG 0.11

像素值变化的原因是什么？ ...如何在不改变像素值的情况下读取和写入视频？ BTW：原始视频已经使用FFMPEG和YUV240像素格式在Windows中编写！

先谢谢了

I have videos which are grayscale (x-ray) ... the problem is when I read and write the videos the pixel value change !!! I print the pixel values as a gray and as BGR and I got values in all of them ... I read the video then I write it using openCV then I re print the pixel value and I see different in the pixel values !!!

I am using openCV 2.4.3 with FFMPEG 0.11 on MAC 10.6.8

why the pixel value changed ? ... how can I read and write the video without changing the pixel value? BTW: the original videos has been written in windows using FFMPEG with YUV240 pixel format !

Thanks in Advance :D

最满意答案

像素值会发生变化，因为openCV默认将帧转换为BGR！ 我猜，读取操作会进行转换过程，为什么像素会发生变化

我希望这可以帮助谁面对这个问题，获得确切的价值，你可以使用FFMPEG读取和写入视频，提供大量的像素格式

The pixels values change because openCV convert the frames to BGR by default ! the reading operation do the conversion process , I guess , that why the pixels change

I hope this can help who face this problem , to get the exact value , you can read and write the videos using FFMPEG which provide a lot of pixel format