realtime frame acquisition while recording video

I wrote a program of video recording and saving and I want add some codes into it to achieve realtime frame acquisition and getting r of rgb of the frames. My code is shown below:

function realtime_test()
global movie name vid;
% Define frame rate
NumberFrameDisplayPerSecond=10;

% Open figure
hFigure=figure(1);

% Set-up webcam video input

vid = videoinput('winvideo', 1);

% Set parameters for video
% Acquire only one frame each time
set(vid,'FramesPerTrigger',1);
% Go on forever until stopped
set(vid,'TriggerRepeat',Inf);
% Get a grayscale image
set(vid,'ReturnedColorSpace','rgb')
vidRes = get(vid, 'VideoResolution');
nBands = get(vid, 'NumberOfBands');
hImage = imshow( zeros(vidRes(2), vidRes(1), nBands));
preview(vid,hImage);
triggerconfig(vid, 'Manual');

% set up timer object
TimerData=timer('TimerFcn', {@FrameRateDisplay,vid},'Period',1/NumberFrameDisplayPerSecond,'ExecutionMode','fixedRate','BusyMode','drop');
name = 'Realtime';
movie=avifile(name,'compression','none');

% Start video and timer object
start(vid);
start(TimerData);

% We go on until the figure is closed
uiwait(hFigure);

% Clean up everything
stop(TimerData);
delete(TimerData);
stop(vid);
delete(vid);
movie=close(movie);
% clear persistent variables
clear functions;

% This function is called by the timer to display one frame of the figure

function FrameRateDisplay(obj, event,vid)
global movie frame;

frame=uint8(getsnapshot(vid));
movie=addframe(movie,frame);

Answer 1

[José-Luis]

If your frame is really rgb data, then the red channel will be:

 your_red = squeeze(frame(:,:,1));

In the future please try posting a minimum working example.

Answer 2

[Xiaochao]

Thanks for your answer, but my problem now is where i should put this function. Becasue i write a timer function to record video and save as AVI file.I am not sure how to get frames while recording exactly. I am a new to use matlab to do video and image processing.

[José-Luis]

Please don't place a comment as an answer. It might get confusing for other people joining the conversation.

You could place the snippet I gave you inside the FrameRateDisplay() function and save the red channel, not the entire frame.

[Xiaochao]

How to save the and export the results of the snippet. The results didn't show in workspace.