I wrote a script that present movie and record from the webcam. The problem is that it rolls the movie in slow motion. I don't think the problem is from taking the snapshot ( I checked it). This is the code:
clear cam
v = VideoReader('movie.MP4');
cam = webcam;
vidWriter = VideoWriter('webcam.avi');
open(vidWriter);
%pre loading the frames
for i=1:50
vtemp = readFrame(v);
vid{i}=vtemp;
end
for index = 1:50
% Acquire frame for processing
img = snapshot(cam);
% Write frame to video
writeVideo(vidWriter, img);
%show the vid frame
imshow(vid{index});
end
close(vidWriter);
clear cam
Any assistance will be much appreciated.
Related
I am reading a filename.mp4 video file in MATLAB. I want to edit the images, however, I want to keep the audio intact. Using VideoReader and VideoWriter only does the images part. I used vision.VideoFileReader and 'vision.VideoFileWriter'. I read the video and audio files, then take the image and add a picture next to it. Then write the frame and the audio associated with it. The final video shows the picture I added, but not the original image. Any help appreciated.
v = VideoReader('movie.mp4');
nfr = v.NumberofFrames;
clear v;
vR = vision.VideoFileReader('movie.mp4','AudioOutputPort',1);
fr = vR.info.VideoFrameRate;
vW = vision.VideoFileWriter('filename.avi','AudioInputPort',1,'FrameRate',fr);
pic = imread('picture.png');%read picture
[a1,b1,~] = size(pic);% get picture size to be resized.
for i = 1:nfr
[I,audio] = vR();
I = permute(I,[2,1,3]);%rotate 90 degrees
if i == 1%resize the picture
[a,b,~] = size(I);
pic = imresize(pic,[a,a/a1*b1]);
end
I = [I pic];%combine picture and movie frame
vW(I,audio);%write frame and audio
end
release(vR);
release(vW);
I figured it out.
v = VideoReader('movie.mp4');
nfr = v.NumberofFrames;
clear v;
vR = vision.VideoFileReader('movie.mp4','AudioOutputPort',1,'VideoOutDataType','uint8');
%default of VideoOutDataType is 'single', converting it to a similar format is essential
fr = vR.info.VideoFrameRate;
vW = vision.VideoFileWriter('filename.avi','AudioInputPort',1,'FrameRate',fr);
pic = imread('picture.png');%read picture
[a1,b1,~] = size(pic);% get picture size to be resized.
for i = 1:nfr
[I,audio] = vR();
I = permute(I,[2,1,3]);%rotate 90 degrees
if i == 1%resize the picture
[a,b,~] = size(I);
pic = imresize(pic,[a,a/a1*b1]);%resizing the pic to same height as movie frame %with proportional width
end
I = [I pic];%combine picture and movie frame
vW(I,audio);%write frame and audio
end
release(vR);
release(vW);
I am creating a video for a presentation with matlab. The video shows a optimization algorithm moving towards the minimum of a costfunction. I want the last seconds of the video to be a freeze-frame, which means that I use the writevideo function to write a couple of identical frames. However when I play the video with VLC player or with powerpoint the correct length of the video is shown, but the identical frames of the video are "skipped". Is there any way I can stop this?
My Code looks like this:
graph = figure('units','pixels','position',[0 0 1920 1080]);
scatter3... %(first frame)
v = VideoWriter('Presentation.avi');
v.Quality = 95;
v.FrameRate = 1;
open(v);
frame = getframe(graph);
writeVideo(v,frame);
for i = 1:10
plot3... %(changing frames)
frame = getframe(graph);
writeVideo(v,frame);
end
for j = 1:5
%(identical frames)
frame = getframe(graph);
writeVideo(v,frame);
end
close(v);
Thank you for answering!
I want to make a video with Matlab using the VideoWriter class. I have several frames of an object as single point clouds and I want to put the frames one after another into my video. As for now, I am doing this like this:
function [] = makeMyVideo(videoPath, framerate, filenamestoplot)
writerObj = VideoWriter(videoPath);
writerObj.FrameRate = framerate;
open(writerObj);
figure;ptHandles = onePlot(filenamestoplot);axis off;view(54,12);
axis tight
set(gca,'nextplot','add');
set(gcf,'Renderer','zbuffer');
firstCameraPos = campos;
for k = 1:numel(filenamestoplot)
pause(0.1);
delete(ptHandles);
ptHandles = onePlot(filenamestoplot(k));axis off;view(54,12);
campos(firstCameraPos);
frame = getframe(gcf);
writeVideo(writerObj,frame);
end
close(writerObj);
end
This works, but my 3D object is "making little jumps". I tried to fix this by setting the camera position for every frame, but unfortunately this did not solve the problem. Do you have any idea, how to fix this?
Thanks!
I'm using Matlab to show the frames in a video sequence , below is my code:
seq=sprintf('walk%d.avi',v); % video's name
videoReader = vision.VideoFileReader(seq);
vidObj = VideoReader(seq);
numFrames = vidObj.NumberOfFrames
for i = 1:numFrames
frame = step(videoReader); % read the next video frame
imshow(frame)
end
Actually it worked fine previously, and i have no idea since when and what caused it to show rotated image . Hope you guys can help me. thank you.
Most updated Matlab function to vertically flip back the frame is:
FlippedFrame = flip(frame,1);
I am currently trying to figure out how to be able to detect a face that is 5m away from the source and will have its facial features clear enough for the user to see. The code i am working on is as shown.
faceDetector = vision.CascadeObjectDetector();
%Get the input device using image acquisition toolbox,resolution = 640x480 to improve performance
obj =imaq.VideoDevice('winvideo', 1, 'YUY2_640x480','ROI', [1 1 640 480]);
set(obj,'ReturnedColorSpace', 'rgb');
figure('menubar','none','tag','webcam');
while (true)
frame=step(obj);
bbox=step(faceDetector,frame);
boxInserter = vision.ShapeInserter('BorderColor','Custom',...
'CustomBorderColor',[255 255 0]);
videoOut = step(boxInserter, frame,bbox);
imshow(videoOut,'border','tight');
f=findobj('tag','webcam');
if (isempty(f));
[hueChannel,~,~] = rgb2hsv(frame);
% Display the Hue Channel data and draw the bounding box around the face.
figure, imshow(hueChannel), title('Hue channel data');
rectangle('Position',bbox,'EdgeColor','r','LineWidth',1)
hold off
noseDetector = vision.CascadeObjectDetector('Nose');
faceImage = imcrop(frame,bbox);
imshow(faceImage)
noseBBox = step(noseDetector,faceImage);
noseBBox(1:1) = noseBBox(1:1) + bbox(1:1);
videoInfo = info(obj);
ROI=get(obj,'ROI');
VideoSize = [ROI(3) ROI(4)];
videoPlayer = vision.VideoPlayer('Position',[300 300 VideoSize+30]);
tracker = vision.HistogramBasedTracker;
initializeObject(tracker, hueChannel, bbox);
while (1)
% Extract the next video frame
frame = step(obj);
% RGB -> HSV
[hueChannel,~,~] = rgb2hsv(frame);
% Track using the Hue channel data
bbox = step(tracker, hueChannel);
% Insert a bounding box around the object being tracked
videoOut = step(boxInserter, frame, bbox);
%Insert text coordinates
% Display the annotated video frame using the video player object
step(videoPlayer, videoOut);
pause (.2)
end
% Release resources
release(obj);
release(videoPlayer);
close(gcf)
break
end
pause(0.05)
end
release(obj)
% remove video object from memory
delete(handles.vid);
I am trying to work on this code to figure out the distance it can cover when tracking a face. I couldnt figure out which one handles that. Thanks!
Not sure what your question is, but try this example. It uses the KLT algorithm, which, IMHO, is more robust for face tracking than CAMShift. It also uses the webcam interface in base MATLAB, which is very easy.