How to play my video while my graph animates?

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matlabuser12
matlabuser12 2015-5-14
回答： Geoff Hayes 2015-5-16
I am trying to update a graph animation in sync with a played movie. How do i structure the while loop so that when the movie(...) line is running the plot loop is running as well?
I have a movie playing using the movie function a la:
movie(video, mov,1,xyloObj.FrameRate)
I am following this code for a graph
%# control animation speed
DELAY = 0.01;
numPoints = 600;
%# create data
x = linspace(0,10,numPoints);
y = log(x);
%# plot graph
figure('DoubleBuffer','on') %# no flickering
plot(x,y, 'LineWidth',2), grid on
xlabel('x'), ylabel('y'), title('y = log(x)')
%# create moving point + coords text
hLine = line('XData',x(1), 'YData',y(1), 'Color','r', ...
'Marker','o', 'MarkerSize',6, 'LineWidth',2);
hTxt = text(x(1), y(1), sprintf('(%.3f,%.3f)',x(1),y(1)), ...
'Color',[0.2 0.2 0.2], 'FontSize',8, ...
'HorizontalAlignment','left', 'VerticalAlignment','top');
%# infinite loop
i = 1; %# index
while true
%# update point & text
set(hLine, 'XData',x(i), 'YData',y(i))
set(hTxt, 'Position',[x(i) y(i)], ...
'String',sprintf('(%.3f,%.3f)',[x(i) y(i)]))
drawnow %# force refresh
%#pause(DELAY) %# slow down animation
i = rem(i+1,numPoints)+1; %# circular increment
if ~ishandle(hLine), break; end %# in case you close the figure
end
I can sync the movement of the red circle by settling delay to my frame rate but i cannot get both to run simultaneously.

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回答（1 个）

Geoff Hayes
Geoff Hayes 2015-5-16
matlabuser12 - rather than calling the movie function, you may want to display the frames yourself so that when a frame appears you update your other figure. Using the xylophone example, instead of
movie(video, mov,1,xyloObj.FrameRate)
you could do
nFrames = xyloObj.NumberOfFrames;
for k=1:nFrames
image(mov(k).cdata,'Parent', axesHandle);
pause(1/xyloObj.FrameRate);
end
where axesHandle is the handle to the parent axes to draw the frame on.
Try integrating the above into your while loop. You don't necessarily need to use the for loop but something similar will be needed to grab the kth frame at each iteration.

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