/usr/share/psychtoolbox-3/PsychDemos/VideoOfflineCaptureDemo.m is in psychtoolbox-3-common 3.0.11.20131230.dfsg1-1build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 | function VideoOfflineCaptureDemo(fullscreen, fullsize, roi, deviceId)
% Demonstrate use of built-in GStreamer video capture engine to capture first
% into memory, then retrieve corresponding video textures after end of capture.
%
% VideoOfflineCaptureDemo([fullscreen=0][, fullsize=0][, roi=[0 0 640 480]][,deviceId=0])
%
% VideoOfflineCaptureDemo initializes the first attached and supported camera on
% your computer (e.g, the built-in iSight of Apple Macintosh computers),
% then records video from it into memory until you press a key. It then
% fetches and displays all previously recorded images, then quits. Abort
% display by pressing any key on the keyboard.
%
% By default, the maximum supported framerate is requested and the
% timecode and interframe interval of each captured image is displayed in
% the top-left corner of the display.
%
% See also ImagingVideoCaptureDemo, VideoDelayloopMiniDemo and a few other
% nice demos.
%
% Optional parameters:
%
% 'fullscreen' If set to non-zero value, the image is displayed in a
% fullscreen window, as usual, otherwise a normal GUI window is used.
%
% 'fullsize' If set to 1, the cameras image is scaled up to full screen
% resolution, ie. so it fills the maximum amount of display area, but
% preserving the original aspect ratio.
%
% 'roi' Selects a rectangular subregion of the camera for display. By
% default, it selects a [0 0 640 480] rectangle, ie. the full are of a
% camera with 640 x 480 pixels resolution. This parameter may need tweaking
% for some cameras, as some drivers have bugs and don't work well with all
% settings.
%
% 'deviceId' Device index of video capture device. Defaults to system default.
%
% History:
% 17.04.2011 mk Written.
AssertOpenGL;
if nargin < 1
fullscreen=[];
end
if isempty(fullscreen)
fullscreen=0;
end;
if nargin < 2
fullsize=[];
end
if isempty(fullsize)
fullsize=0;
end
if nargin < 3
roi = [];
end
if nargin < 4 || isempty(deviceId)
deviceId = [];
end
screenid=max(Screen('Screens'));
try
if fullscreen<1
win=Screen('OpenWindow', screenid, 0, [0 0 800 600]);
else
win=Screen('OpenWindow', screenid, 0);
end;
% Initial flip to a blank screen:
Screen('Flip',win);
% Set text size for info text. 24 pixels is also good for Linux.
Screen('TextSize', win, 24);
% Open framegrabber on specified capture device 'deviceId' with specified
% resolution and region of interest 'roi'. We enforce use of capture engine
% type '3', the GStreamer engine, as only this engine supports offline capture:
grabber = Screen('OpenVideoCapture', win, deviceId, roi, [], [], [], [], [], 3);
% Start videocapture at maximum framerate, do not drop frames, but keep'em all:
[fps, t] = Screen('StartVideoCapture', grabber, realmax, 0);
% Wait for user to stop capture:
DrawFormattedText(win, 'Video capture active.\nPress any key to stop capture\nand start display of the results.', 'center', 'center', 255);
Screen('Flip', win);
KbStrokeWait;
% Stop video capture without discarding all internally stored frames, so we can fetch'em later:
Screen('StopVideoCapture', grabber, 0);
% Fetch loop: Fetches and displays all captured images until keypress or all images
% are used up:
dstRect = [];
oldpts = 0;
count = 0;
tex=0;
while 1
if KbCheck
break;
end;
[tex pts nrpending] = Screen('GetCapturedImage', win, grabber, [], tex); %#ok<NASGU>
if tex > 0
% fprintf('tex = %i pts = %f nrpending = %i\n', tex, pts, nrpending);
% Perform first-time setup of transformations, if needed:
if fullsize && (count == 0)
texrect = Screen('Rect', tex);
winrect = Screen('Rect', win);
sf = min([RectWidth(winrect) / RectWidth(texrect) , RectHeight(winrect) / RectHeight(texrect)]);
dstRect = CenterRect(ScaleRect(texrect, sf, sf) , winrect);
end
% Draw new texture from framegrabber.
Screen('DrawTexture', win, tex, [], dstRect);
% Print pts as delta since start of capture:
Screen('DrawText', win, sprintf('%.4f', pts - t), 0, 0, 255);
if count>0
% Compute delta:
delta = (pts - oldpts) * 1000;
oldpts = pts;
% Display delta between successive frames in msecs:
Screen('DrawText', win, sprintf('%.4f', delta), 0, 20, 255);
end;
% Show it.
Screen('Flip', win);
else
% Done with fetching.
break;
end;
count = count + 1;
end;
% Close capture device: This will release all not yet fetched images:
Screen('CloseVideoCapture', grabber);
% Close window, clean up.
Screen('CloseAll');
catch
Screen('CloseAll');
end;
|