>Psychtoolbox>PsychDemos>MovieDemos

PlayMoviesDemo(moviename [, hdr=0][, backgroundMaskOut][, tolerance][, pixelFormat=4][, maxThreads=-1])

This demo accepts a pattern for a valid moviename, e.g.,
moviename=\*.mpg, then it plays all movies in the current working
directory whose names match the provided pattern, e.g., the \*.mpg
pattern would play all MPEG files in the current directory.

If you don’t specify a moviename, the demo will ask you if it should play
our standard DualDiscs.mov demo movie, or rather play through a set of
videos in a playlist which are streamed from the internet. These ‘c’ool
videos may provide you with useful information for your daily work.

This demo uses automatic asynchronous playback for synchronized playback
of video and sound. Each movie plays until end, then rewinds and plays
again from the start. Pressing the Cursor-Up/Down key pauses/unpauses the
movie and increases/decreases playback rate. The ‘c’ key toggles a mouse
color picker that tells you the color values of the pixel roughly under
the mouse cursor position.

The left- right arrow keys jump in 1 seconds steps. SPACE jumps to the
next movie in the list. ESC ends the demo.

If the optional flag ‘hdr’ is specified as non-zero, then the demo
expects the onscreen window to display on a HDR-10 capable display device
and system, and tries to switch to HDR mode. If the operating system+gpu
driver+gpu+display combo does not support HDR, the demo will abort with
an error. Otherwise it will expect the movies to be HDR-10 encoded and
try to display them appropriately. A flag of 1 does just that. A flag of 2 will
manually force the assumed EOTF of movies to be of type PQ, iow. assume the movie
is a HDR-10 movie in typical Perceptual Quantizer encoding. This is useful if you
want to play back HDR content on a system with a [GStreamer](GStreamer) version older than
1.18.0 installed, where [GStreamer](GStreamer) is not fully HDR capable, but this hack may
get you limping along. Another restriction would be lack of returned HDR metadata,
so if your HDR display expects that, you will not get the best possible quality.
Upgrading to [GStreamer](GStreamer) 1.18 or later is advised for HDR playback.
A flag of 3 or 4 will use an alternative HDR display method only available on
Linux/X11, with 4 applying the same hack to cope with older [GStreamer](GStreamer) versions
as a setting of 2.

If the optional RGB color vector backgroundMaskOut is provided, then
color pixels in the video which are equal or close to backgroundMaskOut will be
discarded during drawing. E.g., backgroundMaskOut = [1 1 1] would
discard all white pixels, backgroundMaskOut = [0 0 0] would discard all
black pixels etc. The optional tolerance parameter allows for some
lenience, e.g., tolerance = 0.01 would discard all pixels whose euclidean
distance in RGB color space is less than 0.01 units to the backgroundMaskOut
color. Background color masking requires a graphics card with fragment
shader support and will fail otherwise.

If the optional pixelFormat is specified, it is used to choose
optimized video playback methods for specific content. Valid values are 1
or 2 for greyscale video playback, and 7 or 8 for optimized grayscale
video playback on modern GPU’s with GLSL shading support. Values 3, 4, 5
and 6 play back color video. 4 is the default, 5 or 6 may provide
significantly improved playback performance on modern GPUs.

If the optional maxThreads is specified, it defines the maximum number
of parallel processing threads that should be used by multi-threaded
video codecs for playback. A setting of n selects n threads, a setting of
zero asks to auto-select an optimum number of threads for a given
computer. By default, a codec specific default number is used, typically
one thread.