Question

我尝试使用此代码提取某些视频的所有帧（每个帧包含大约13000帧），但是提取所有帧需要太长时间。还有更快捷的方法吗？

    filename = 'S.avi';
mov = VideoReader(filename);

% Output folder

outputFolder = fullfile(cd, 'S');
mkdir(outputFolder);


%getting no of frames
framee=100000;
numberOfFrames = mov.NumberOfFrames;
numberOfFramesWritten = 0;
for frame =       1:12525

    thisFrame = read(mov, frame);
    framee=framee+1;
    outputBaseFileName = sprintf('%3.3d.png', framee);
    outputFullFileName = fullfile(outputFolder, outputBaseFileName);
    imwrite(thisFrame, outputFullFileName, 'png');
%     progressIndication = sprintf('Wrote frame %4d of %d.', frame,numberOfFrames);
%     disp(progressIndication);
    numberOfFramesWritten = numberOfFramesWritten + 1;

end
progressIndication = sprintf('Wrote %d frames to folder "%s"',numberOfFramesWritten, outputFolder);
disp(progressIndication);

Answer 1

从概念上讲，这与你正在做的事情并没有太大的不同，但你的代码中有许多迂回的步骤。

大概你可以这样做：

mov = VideoReader(filename);
vidFrames = read(mov);

要将电影收集为4D阵列，然后执行

for frame = 1 : size(vidFrames, 4)
    outputBaseFileName = sprintf('%3.3d.png', frame);
    outputFullFileName = fullfile(outputFolder, outputBaseFileName);
    imwrite( vidFrames(:,:,:,frame), outputFullFileName, 'png');
end

它可能会更快。此外，您可以使用parfor（或spmd代替计数器函数句柄）来进一步并行化

用matlab提取视频帧

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