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Kartik Thakore
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SDL::Overlay - YUV Video overlay


Core, Video, Structure


First import the following modules to get access to constants and functions needed for overlay.

   use SDL;
   use SDL::Video;
   use SDL::Overlay;

Init the video susbsystem.


Create a display to use.

   my $display = SDL::Video::set_video_mode(640, 480, 32, SDL_SWSURFACE);

Create and attach the display to a new overlay

   my $overlay = SDL::Overlay->new( 100, 100, SDL_YV12_OVERLAY, $display);


A SDL_Overlay allows for video rendering on an SDL_Surface which is a display.

The term 'overlay' is a misnomer since, unless the overlay is created in hardware, the contents for the display surface underneath the area where the overlay is shown will be overwritten when the overlay is displayed.


new ( $width, $height, $YUV_flag, $display)

The constructor creates a SDL::Overlay of the specified width, height and format (see YUV_Flags list below of available formats), for the provided display.

Note the 'display' argument needs to actually be the surface created by SDL::Video::SetVideoMode otherwise this function will segfault.

   my $overlay = SDL::Overlay->new( $width, $height, $YUV_flag, $display );


More information on YUV formats can be found at http://www.fourcc.org/indexyuv.htm .

  • SDL_YV12_OVERLAY 0x32315659 /* Planar mode: Y + V + U */

  • SDL_IYUV_OVERLAY 0x56555949 /* Planar mode: Y + U + V */

  • SDL_YUY2_OVERLAY 0x32595559 /* Packed mode: Y0+U0+Y1+V0 */

  • SDL_UYVY_OVERLAY 0x59565955 /* Packed mode: U0+Y0+V0+Y1 */

  • SDL_YVYU_OVERLAY 0x55595659 /* Packed mode: Y0+V0+Y1+U0 */


Overlay format (see YUV_Flags)

w, h

Width and height of overlay


Number of planes in the overlay. Usually either 1 or 3


An array of pitches, one for each plane. Pitch is the length of a row in bytes.


As of release 2.3 direct right to overlay is disable.

An array of pointers to the data of each plane. The overlay should be locked before these pointers are used.

see SDL::Video::lock_YUV_overlay, SDL::Video::unload_YUV_overlay


This will be set to 1 if the overlay is hardware accelerated.