How can I save the video file from matlab videoPlayer
16 views (last 30 days)
Show older comments
How can I save the video file from matlab videoPlayer? I want to export the processed video https://kr.mathworks.com/help/vision/examples/detecting-cars-using-gaussian-mixture-models.html Or how can I change the videoPlayer to videoWriter command?
foregroundDetector = vision.ForegroundDetector('NumGaussians', 3, ...
'NumTrainingFrames', 50);
videoReader = vision.VideoFileReader('visiontraffic.avi');
for i = 1:150
frame = step(videoReader); % read the next video frame
foreground = step(foregroundDetector, frame);
end
figure; imshow(frame); title('Video Frame');
figure; imshow(foreground); title('Foreground');
se = strel('square', 3);
filteredForeground = imopen(foreground, se);
figure; imshow(filteredForeground); title('Clean Foreground');
blobAnalysis = vision.BlobAnalysis('BoundingBoxOutputPort', true, ...
'AreaOutputPort', false, 'CentroidOutputPort', false, ...
'MinimumBlobArea', 150);
bbox = step(blobAnalysis, filteredForeground);
result = insertShape(frame, 'Rectangle', bbox, 'Color', 'green');
numCars = size(bbox, 1);
result = insertText(result, [10 10], numCars, 'BoxOpacity', 1, ...
'FontSize', 14);
figure; imshow(result); title('Detected Cars');
videoPlayer = vision.VideoPlayer('Name', 'Detected Cars');
videoPlayer.Position(3:4) = [650,400]; % window size: [width, height]
se = strel('square', 3); % morphological filter for noise removal
while ~isDone(videoReader)
frame = step(videoReader); % read the next video frame
% Detect the foreground in the current video frame
foreground = step(foregroundDetector, frame);
% Use morphological opening to remove noise in the foreground
filteredForeground = imopen(foreground, se);
% Detect the connected components with the specified minimum area, and
% compute their bounding boxes
bbox = step(blobAnalysis, filteredForeground);
% Draw bounding boxes around the detected cars
result = insertShape(frame, 'Rectangle', bbox, 'Color', 'green');
% Display the number of cars found in the video frame
numCars = size(bbox, 1);
result = insertText(result, [10 10], numCars, 'BoxOpacity', 1, ...
'FontSize', 14);
step(videoPlayer, result); % display the results
end
release(videoReader); % close the video file
1 Comment
KD IS
on 28 Oct 2019
videoReader = vision.VideoFileReader('visiontraffic.avi');
videoFWriter=vision.VideoFileWriter('result.avi',...
'FrameRate',videoReader.info.VideoFrameRate);
...
...
step(videoPlayer, result); % display the results
step(videoFWriter,result); % saves video
...
...
release(videoReader); % close the videoReader
release(videoFWriter); % close the videoWriter
Answers (2)
Harish Ramachandran
on 17 Jan 2018
Edited: Harish Ramachandran
on 17 Jan 2018
In the piece of code you attached above, you are using a VideoReader in order to get the individual frames and implement the car detection algorithm.
In a similar manner, you need to create a VideoWriter object in order to write the frames and process/save them into a video.
(Think of it as 'fread' and 'fwrite' but for video files)
Start a 'for' loop and use the 'open' command. Inside the loop, you will need to use the method 'writeVideo'. Then close the file after the loop.
video_object = VideoWriter('getframes');
open(video_object);
for i = 1:number of input frames
writeVideo(video_object, format, other options);
end
close(video_object );
Reference:
Vemana
on 6 Sep 2023
Create a video reader named turtleVideo for the video file turtles.avi.
0 Comments
See Also
Categories
Find more on Feature Detection and Extraction in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!