在Matlab中逐帧循环播放视频文件

Question

I need to loop through a video file in matlab frame by frame manipulate every frame (for image background substracting) and save the result to a new file, I cant figure out how to do that though because i am using VideoReader and VideoWriter libs and I cant figure out how to do that. DISCLAIMER - this is for a hw assignment I would like to get only the answer of how to use the VideoReader and VideoWriter in a for loop (for the whole movie) as for the image substraction - I will handle this myself... thanks in advance...

Answer 1

I have never needed to work on videos, but looking at the Mathworks documentation for VideoReader and VideoWriter I came up with the following code to read from an mp4 file, optionally change the video, and write to an avi file.

vidIn = VideoReader('sample_mpeg4.mp4');
vidOut = VideoWriter('sample_out');
open(vidOut)
for ii = 1:vidIn.NumberOfFrames;
  pic = read(vidIn, ii);
  % Optional processing of 'pic' here
  writeVideo( vidOut, pic);
end
close(vidOut)

I want to note that I could not get MATLAB to read my original .avi file, however, it wrote the video just fine, and I was able to play it without a problem.