matlab截取一段视频和裁剪一小块视频区域

截取一段视频的400帧~600帧

function [vidFile,samplingRate] = Get_Vedio()

addpath(genpath('.'));
global inFile;

%截取一段视频

vidFile='myfile.avi';
vObj = VideoReader(vidFile);
%截取400帧~600帧
myMovie = read(vObj,[400 600]);
myVideo = VideoWriter('.\result\myfile400.avi', 'Uncompressed AVI');
myVideo.FrameRate = 20;
open(myVideo);
writeVideo(myVideo, myMovie);
vidFile = 'myfile400.avi';

裁剪一小块视频区域，主要采用imcrop函数

function [outfilename,fr] = FirstFrameFaceDet(infilename,handles)
%第一步：检测参考帧
% Create a cascade detector object.
addpath(genpath('.'));
global infilename;


infilename='cdd.mp4'
% Read a video frame and run the detector. data\cdd.mp4
vidFile =  fullfile('data', infilename);
outfilename = [infilename(1:end-4),'_1st.avi'];
outName =  fullfile('result',outfilename);


vid = VideoReader(vidFile);
fr = round(vid.FrameRate);
len = vid.NumberOfFrames;


%%输出文件创建
vidOut = VideoWriter(outName);
vidOut.FrameRate = 20;
open(vidOut)


videoFileReader = vision.VideoFileReader(vidFile);
videoFrame      = step(videoFileReader);
imshow(videoFrame);
%drawnow


%手动标记选择区域，bbox四个参数分别对应剪裁后左上角像素在原图像位置，剪裁后图像宽和高
bbox=[300 300 250 180];


boxInserter  = vision.ShapeInserter('BorderColor','Custom',...
    'CustomBorderColor',[255 0 0],'LineWidth',3);
videoOut_chest = step(boxInserter, videoFrame,bbox);
%videoOut_chest = step(boxInserter, videoOut_chest,bbox_right);
figure(1),imshow(videoOut_chest,'border','tight');title('Detected image');


%%第一帧图像裁剪
faceImage    = imcrop(videoFrame,bbox);
%    axes(handles.axes4);
    imshow(faceImage);
    drawnow
writeVideo(vidOut,im2uint8(faceImage));
h=waitbar(0,'开始检测...','Name','正在跟踪...');
%第二步：裁剪其他帧
n=1;
% Track the bbox over successive video frames until the video is finished.
while ~isDone(videoFileReader)
    n=n+1;
    % Extract the next video frame
    videoFrame = step(videoFileReader);
    % Insert a bounding box around the object being tracked
    % videoOut = step(boxInserter, videoFrame, bbox);
    faceImage    = imcrop(videoFrame,bbox);
    % Display the annotated video frame using the video player object
    % step(videoPlayer, faceImage);
    writeVideo(vidOut,im2uint8(faceImage));
    h=waitbar(0.05+n*(0.85/len),h,[num2str(floor(100*(0.05+n*(0.85/len)))),'%']);
end


% Release resources
close(vidOut);
h=waitbar(0.9,h,[num2str(90),'%']);
release(videoFileReader);
h=waitbar(1,h,[num2str(1),'%']);
clear vid;
close(h)
 %axes(handles.axes3);
    cla
 %axes(handles.axes4);
    cla
drawnow