I was wondering if there is any tool or if there is any way in order to take from a gif file, and save a file for each image.
This way I can get each frame separated in a file.
Using python
A script made in python is available here:
import os
from PIL import Image
def extractFrames(inGif, outFolder):
frame = Image.open(inGif)
nframes = 0
while frame:
frame.save( '%s/%s-%s.gif' % (outFolder, os.path.basename(inGif), nframes ) , 'GIF')
nframes += 1
try:
frame.seek( nframes )
except EOFError:
break;
return True
extractFrames('ban_ccccccccccc.gif', 'output')
ban_ccccccccccc.gif is the name of your GIF image, and output the name of the folder were the frames will be saved.
Related
My images are in mat file after I cropped them with a particular size 256x256, the size was correct before writing in png file. I saved them in png format. Now, I wanted to process them and realized that the sizes are not same, what is the reason? And how can I solve it? Thanks
This the code:
[m1,m2] = size(II);
i1_start = floor((m1)/2)-floor(n/2); % or round instead of floor; using neither gives warning
i1_stop = i1_start + n;
i2_start = floor((m2)/2)-floor(n/2);
i2_stop = i2_start + n;
B = II(i1_start+1:i1_stop, i2_start+1:i2_stop);
figure ,imshow(B,[]);
and this is the code for png conversion:
outfile = sprintf(png_filename)
data=uint8(data);
imwrite(data,outfile,'png','BitDepth' ,8);
Use imwrite function
A = rand(50);
imwrite(A,'myGray.png')
I need to save all the captured images in MATLAB but I am able to save one picture at a time.
mycam = webcam();
img = snapshot(mycam);
imwrite(img,'img.jpg');
If somebody knows how to save all the pictures taken at a time in MATLAB, please help me with the code.
I would save the images as a movie and then access the frames later. This is untested but it would work like this.
mycam = webcam();
% if you know the number of images use that here
% a movie is just a collection of frames
% if not then just don't initialize F
F(nFrames) = struct('cdata', [], 'colormap, []);
for i = 1:nFrames
F(i) = im2frame(snapshot(mycam));
end
% save F
movie2avi(F, 'MyMovie.avi', 'compression', 'None');
Then you can load the movie and look at the frames. This example uses the older movie2avi but VideoWriter is also an option
v = VideoWriter('MyMovie.avi');
open(v);
for i = 1:nFrames
writeVideo(v, snapshot(mycam));
end
close(v);
Again untested as I don't have a webcam attached to this computer. But it works for animated graphs. See doc readFrame for the way to read frames
As they have already told you, you should use a for loop with the sprintf function in order to not overwrite the previous images. Try with the following command:
%capture the frames
for i =1:n;% n is the number of frames you want to capture
frames{i} = getsnapshot(mycam);
end
%save in the current folder
for i = 1:n;
imwrite(frames{i}, sprintf('imageName%d.jpg',i))
end
You will have all the captured frames saved in the Current Folder.
I'm trying to convert a video file into greyscale. When I try running the Matlab script I get a "Invalid video data-must be a numeric or logical data type". Can someone help me with what I am doing wrong? I am also new to matlab.
filename = 'Project1.m4v';
vid = VideoReader(filename);
newVid = VideoWriter('NewVid');
open(newVid);
numFrames = vid.NumberOfFrames;
for frame = 1 : numFrames
% Extract the frame from the movie structure.
thisFrame = read(vid, frame);
%Convert each frame to black and white
gray = rgb2gray(thisFrame);
writeVideo(newVid,gray);
end
close(newVid);
implay(newVid);
Use implay('NewVid.avi') instead of implay(newVid);
The only problem in your code is the last line: implay(newVid);.
newVid is a VideoWriter object - you create it using newVid = VideoWriter('NewVid');.
I recommend you to add '.avi' file extension to 'NewVid' file name:
Use: newVid = VideoWriter('NewVid.avi');
implay does't take VideoWriter object as input parameter.
Instead of displaying an error message in Matlab workspace, it displays the error message in the video window.
All you need to do, is replacing last code line with implay('NewVid.avi').
I am newly working with Matlab. I want to read a video file and do some calculations every frame and display every frame. I wrote the following code but every time it only displays the first frame. can anybody please help.
mov=VideoReader('c:\vid\Akiyo.mp4');
nFrames=mov.NumberOfFrames;
for i=1:nFrames
videoFrame=read(mov,i);
imshow(videoFrame);
end
Note: mmreader API has been discontinued by MATLAB so prefer using VideoReader.
See comment by #Vivek.
I usually do this:
obj=mmreader('c:\vid\Akiyo.mp4');
nFrames=obj.NumberOfFrames;
for k=1:nFrames
img=read(obj,k);
figure(1),imshow(img,[]);
end
As far as your code is concerned, I saw MATLAB's documentation. You should do the things in following order:
mov=VideoReader('c:\vid\Akiyo.mp4');
vidFrames=read(mov);
nFrames=mov.NumberOfFrames;
for i=1:nFrames
imshow(vidFrames(:,:,i),[]); %frames are grayscale
end
Function read() and the field NumberOfFrames() are now deprecated, Matlab suggests using
xyloObj = VideoReader(file);
vidHeight = xyloObj.Height;
vidWidth = xyloObj.Width;
mov = struct('cdata',zeros(vidHeight, vidWidth, 3,'uint8'), 'colormap',[]);
while hasFrame(xyloObj)
mov(k).cdata = readFrame(xyloObj,'native');
end
In case you want to estimate a number of frames in the video, use nFrames = floor(xyloObj.Duration) * floor(xyloObj.FrameRate);
Below suggested code is showing only one frame
imshow(vidFrames(:,:,i),[]);
I am doing following things to store each frame
obj = VideoReader('path/to/video/file');
for img = 1:obj.NumberOfFrames;
filename = strcat('frame',num2str(img),'.jpg');
b = read(obj,img);
imwrite(b,filename);
end
This will store all the frames in your home directory.And yes, as also suggested by Vivek and Parag
You need to use VideoReader as mmreader has been discontinued by
MATLAB.
*=I was making a function to play any .avi file as a set of frames in a figure. Here's what a did. A bit of a combo of what you've done, except my NumberOfFrames wasn't working: (noteL this also shows it in colour)
function play_video(filename)
% play_video Play a video file
% play_video(filename) plays the video file specified by filename in a MATLAB Figure window.
figure
set(figure, 'Visible', 'on')
mov=VideoReader(filename);
vidFrames=read(mov);
duration = mov.Duration;
frame_rate = mov.FrameRate;
total_frames = duration .* frame_rate
for i=1:1:total_frames
imshow(vidFrames(:, :, :, i), []);
drawnow
end
I run this code in MATLAB but it returns a Cyan frame
obj = videoinput('winvideo', 1);
% Select the source to use for acquisition.
set(obj, 'SelectedSourceName', 'input1')
% View the properties for the selected video source object.
src_obj = getselectedsource(obj);
get(src_obj)
% Acquire and display a single image frame.
frame = getsnapshot(obj);
image(frame);
% Remove video input object from memory.
delete(obj);
But preview video works well.
Perhaps the problem is with the input to image command.
Try to run
class(frame)
max(frame(:))
min(frame(:))
And see what the results are.
Double values should be between [0-1], whereas uint8 should be in the range of [0-255].
Adding obj.ReturnedColorSpace = 'rgb'; in the second line solved it.