According to my understanding, you want to play the video and plot pressure variation with time along with that. You can achive that by two subplots one for playing the video feed and the other for plotting the pressure data. You can use the matlab class "VideoReader" for reading the frames of you video file.
Consider the following example as a guideline to achieve your goal. Make sure the initial and final experiment times of the video matches with that of pressure data.
%% Setup the subplots
ax1 = subplot(2,1,1); % For video
ax2 = subplot(2,1,2); % For pressure plot
%% Setup VideoReader object
filename = 'SomeVideoFileName';
v = VideoReader(filename);
nFrames = v.Duration*v.FrameRate; % Number of frames
% Display the first frame in the top subplot
vidFrame = readFrame(v);
image(vidFrame, 'Parent', ax1);
ax1.Visible = 'off';
%% Load the pressure data
t = 0:0.01:v.Duration; % Cooked up for this example, use your actual data
y = sin(t);
nDataPoints = length(t); % Number of data points
step = round((nDataPoints/nFrames));
index = 1:step:nDataPoints;
i = 2;
% Diplay the plot corresponds to the first frame in the bottom subplot
h = plot(ax2,t(1:index(i)),y(1:index(i)),'-k');
% Fix the axes
ax2.XLim = [t(1) t(end)];
ax2.YLim = [min(y) max(y)];
%% Animate
while hasFrame(v)
pause(1/v.FrameRate);
vidFrame = readFrame(v);
image(vidFrame, 'Parent', ax1);
ax1.Visible = 'off';
i = i + 1;
set(h,'YData',y(1:index(i)), 'XData', t(1:index(i)))
end
Note: This example considers "nDataPoints > nFrames". The other condition can be handled similarly.
