Create an MP4 video from a set of 16 bit images (mono)

Question

Jason 2023-6-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1983164-create-an-mp4-video-from-a-set-of-16-bit-images-mono

回答： Jason 2023-6-14

Hello, I have a cell array of images (app.imgArray) that are all 16 bit. Im trying to output them as a video file (preferable mp4), but Im not having any sucess yet. I've realised that the format has to be either double or unit8 (from error messages!), so when I convert to uint8, the code finishes, however, the mp4 video file is just white.

it also seems to ignore the frame rate=1 I code. It reads back 30fps.

   dt = datestr(now,'dd-mmm-yyyy HH-MM-SS');   %get current dateTime 
            filepath='F:\Temp\';
            filename=fullfile(filepath,[dt,'- VidMatlab.mp4']);
            diskLogger=VideoWriter(filename,'MPEG-4');   % Use the MPEG-4 Codec
            disklogger.FrameRate=1;    %only have about 8 images and want to see them.
            open(diskLogger);
            ReportMessage(app,'..Disklogger Opened');   %My reporting function 
            
            data=app.imgArray;
            class(data{1})
            numFrames=size(data,2);
            ReportMessage(app,['..Recording To Disk Started ', num2str(numFrames)]);
            for x=1:numFrames
                 writeVideo(diskLogger, uint8(app.imgArray{x}));
            end
            ReportMessage(app,'DiskLogger Stopped');           
            
            
            close(diskLogger);
            
             disp('Finished Saving Video')
             %check
             disp('checking file')
             v = VideoReader(filename);
             fr=v.FrameRate;   %double
             dur=v.Duration;
             ReportMessage(app,['Video Saved as: ',filename, ' @',num2str(fr),'fps  (',num2str(dur,'%.1f'),' s)']);   

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Richard Burnside 2023-6-14

In the past I have found it necessary to render each frame on a figure then use "getframe" before encoding the frame to video. That was years ago so maybe that it no longer necessary.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Jason 2023-6-14

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1983164-create-an-mp4-video-from-a-set-of-16-bit-images-mono#answer_1255924

在 MATLAB Online 中打开

I think I've nearly done it myself.

1: The framerate issue was just a typo (missed the capital "L"

it should be diskLogger.FrameRate=1; instead of disklogger.FrameRate=1;

2: I can now see the video, i.e. its no longer white by dividing by 256 when I cast to uint8.

writeVideo(diskLogger, uint8(app.imgArray{x}/256));

They are however slightly darker than the full 16 bit. Are there any tricks to try to lighten up the images (video) more - i.e. make the darker areas a bit more lighter rather than black?

Thanks