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function PlayMoviesWithoutGapDemoOSX(moviename)
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% PlayMoviesWithoutGapDemoOSX(moviename)
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% This demo accepts a pattern for a valid moviename, e.g.,
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% moviename='*.mpg', then it plays all movies in the current working
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% directory whose names match the provided pattern, e.g., the '*.mpg'
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% pattern would play all MPEG files in the current directory.
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% Pressing ESC ends the demo.
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% Movies are played one after each other. We try to minimize perceptible
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% gaps between end of movie i and start of movie i+1 by asynchronous
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% loading: While movie i is played back, we ask Psychtoolbox to load the
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% next movie i+1 in the background, so startup time for movie i+1 will be
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% minimized. This feature is currently only supported on MacOS-X and it
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% doesn't work well with movies that have sound tracks. The reason for this
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% is currently unknown, but it leads to frequent lockups of the playback
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% engine. How well this feature works depends strongly on the computational
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% horsepower of your machine. Slow machines will probably stutter...
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moviename = '*.mov' %#ok<NOPRT>
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% Switch KbName into unified mode: It will use the names of the OS-X
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% platform on all platforms in order to make this script portable:
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KbName('UnifyKeyNames');
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background=[128, 128, 128];
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% Open onscreen window:
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screen=max(Screen('Screens'));
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win = Screen('OpenWindow', screen, background);
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% Initial display and sync to timestamp:
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% Return full list of movie files from directory+pattern:
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moviefiles=dir(moviename);
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for i=1:size(moviefiles,1)
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moviefiles(i).name = [ pwd filesep moviefiles(i).name ];
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% Playbackrate defaults to 1:
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% Load first movie. This is a synchronous (blocking) load:
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moviename=moviefiles(mod(iteration, size(moviefiles,1))+1).name;
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[movie movieduration fps imgw imgh] = Screen('OpenMovie', win, moviename);
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% Start playback of movie. This will start
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% the realtime playback clock and playback of audio tracks, if any.
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% Play 'movie', at a playbackrate = 1, with 1.0 == 100% audio volume.
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Screen('PlayMovie', movie, rate, 0, 1.0);
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% Endless loop, runs until ESC key pressed:
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% Show basic info about movie:
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fprintf('ITER=%i::', iteration);
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fprintf('Movie: %s : %f seconds duration, %f fps, w x h = %i x %i...\n', moviename, movieduration, fps, imgw, imgh);
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% Get moviename of next file:
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iteration=iteration + 1;
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moviename=moviefiles(mod(iteration, size(moviefiles,1))+1).name;
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% Playback loop: Fetch video frames and display them...
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% Return next frame in movie, in sync with current playback
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% tex either the texture handle or zero if no new frame is
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% ready yet. pts = Presentation timestamp in seconds.
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[tex pts] = Screen('GetMovieImage', win, movie, 1);
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% Valid texture returned?
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% No. This means that the end of this movie is reached.
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% We exit the loop and prepare next movie:
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% Yes. Draw the new texture immediately to screen:
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Screen('DrawTexture', win, tex);
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Screen('Close', tex);
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% Check for abortion by user:
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[keyIsDown,secs,keyCode]=KbCheck;
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if (keyIsDown==1 && keyCode(esc))
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% Set the abort-demo flag.
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% We start background loading of the next movie 0.5 seconds
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% after start of playback of the current movie:
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if prefetched==0 && pts > 0.5
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% Initiate background async load operation:
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% We simply set the async flag to 1 and don't query any
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Screen('OpenMovie', win, moviename, 1);
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% If asynchronous load of next movie has been started already
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% and we are less than 0.5 seconds from the end of the current
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% movie, then we try to finish the async load operation and
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% start playback of the new movie in order to give processing a
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if prefetched==1 && movieduration - pts < 0.5
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% Less than 0.5 seconds until end of current movie. Try to
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% start playback for next movie:
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% Open the movie - this should take zero-time as the movie
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% should have been already prefetched during playback of
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% the current movie. In case loading did not finish, this
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% command will pause Matlabs execution until the movie is
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[newmovie newmovieduration newfps newimgw newimgh] = Screen('OpenMovie', win, moviename);
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Screen('PlayMovie', newmovie, rate, 0, 1.0);
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telapsed = GetSecs - t1 %#ok<NOPRT,NASGU>
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finalcount=i %#ok<NOPRT,NASGU>
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% Done with old movie. Stop its playback:
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Screen('PlayMovie', movie, 0);
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% Close movie object:
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Screen('CloseMovie', movie);
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% Ok, now our 'newmovie' becomes the current 'movie':
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movieduration = newmovieduration;
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% As playback of the new movie has been started already, we can
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% simply reenter the playback loop:
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% End of movie playback. Shut down and exit:
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% A prefetch operation for a movie is still in progress. We need to
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% finalize this cleanly by waiting for the movie to open and then
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newmovie = Screen('OpenMovie', win, moviename);
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% Playback of a new prefetched movie has been started. We need to stop and
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Screen('PlayMovie', newmovie, 0);
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Screen('CloseMovie', newmovie);
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Screen('Close', win);
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% Error handling: Close all windows and movies, release all ressources.
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Psychtoolbox/PsychDemos/QuicktimeDemos/PlayMoviesWithoutGapDemoOSX.m
