Matlab VideoWriter is very slow

21 次查看（过去 30 天）

timo 2018-7-30

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/412807-matlab-videowriter-is-very-slow

编辑： Jan 2018-8-3

So i am trying to cut an mp4 file , and remove the last 20% I go from start :) and i have this code where 5833 is the last frame i want to write

videoFReader = vision.VideoFileReader('2018-07-30_21h52_48.mp4');
videoFWriter = vision.VideoFileWriter('myFile.avi','FrameRate',...
    videoFReader.info.VideoFrameRate);
for i=1:5833
    videoFrame = step(videoFReader);
    step(videoFWriter,videoFrame);
end

I observed that : 1. My CPU is used around 25% (only one core from 8) 2. the process is very slow - the original file is 45 Mb but 5 minutes passed and is still at 80% done ..

Any workaround to make it faster (use GPU / or multi core ) ? For a professional product this is kinda of embarrassing :(

11 个评论
显示 9更早的评论隐藏 9更早的评论

OCDER 2018-8-1

编辑：OCDER 2018-8-1

I really do support your efforts to make a multithreaded video WRITER, not multithreaded video processor or reader. VideoWriter is slow for you and others, and you'll be doing yourself and others a favor. The multithreaded video writer would be great - just ignore my skepticism, as that comes from my ignorance.

"for sure you can write from 8 processes in parallel on the hard drive ." "Well i can make a demo where i have a file with..." "If i cannot do it..."

So can you or can you not do it???

"If you pay me 50 bucks i can make the demo... If i cannot do it i will pay u 50 bucks."

No. Why pay you 50 before you make something, and if you fail, you just return (or not return) 50? Sounds unfair.... Plus, it's maybe a violation of forum policy to request money for code/service.

https://www.mathworks.com/matlabcentral/termsofuse.html#content

"Content that you submit must be offered free of charge. You may not use the Site to sell or market your products or services to others."