Member Avatar for banGerprawN

Im using a Radeon 9800pro with VGA, DVI and S-Video out. I have 2 projectors that i plan on using in a widescreen setup side by side for a digital video display im doing. My problem is this:
Both projectors are attached, one to the VGA-out, and one to the DVI-out on my video card. They both work fine, in either mirrored configuration or extended desktop, but I want to be able to play back both video files and possibly TV stations through my TV tuner, and I cannot find any information on how to do this.
Some help, PLEASE!

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Short summary and practical fixes tied to the thread: described the classic case—two heads on a single Radeon and a desire to play video stretched across both projectors. The usual root cause is the hardware overlay used by many Windows-era players: most GPUs expose a single hardware overlay/special video surface and that surface is generally usable on one display/head at a time, so a fullscreen overlay-backed video will not span an extended desktop. (virtualdub.org)

Software workaround (fast test you can try)

  1. Put Windows into Extended Desktop (side-by-side).
  2. In the player, switch the video output to a non-overlay renderer (DirectShow VMR-9/VMR9 windowed or the newer EVR/Direct3D-based renderers) or use a player that renders via ordinary Direct3D/GDI.
  3. Disable any "use hardware overlay" or exclusive overlay option, then stretch the player window across both monitors and play. VMR-9 and similar renderers are designed to use Direct3D surfaces (not the single hardware overlay), so spanning a window across multiple monitors becomes possible. (learn.microsoft.com)

Driver/hardware options (more robust)

  • Use driver-level spanning so the OS sees one wide desktop: Nvidia nView (Horizontal/Vertical Span) or Matrox multi-display solutions let the driver present a single large desktop across outputs. That makes video behave as one big surface. (nvidia.com)
  • For TV-tuner sources that only output via overlay, either get tuner software that can render through VMR/EVR (software renderer) or duplicate the tuner output with an external distribution amplifier/splitter (feed the same analog/digital signal to both projectors) to guarantee identical display on both devices. (hauppage.com)

Notes: correctly pointed to the overlay limitation; is also correct that some ATI chipsets offered multi-adapter features (SurroundView) on certain platforms. If seamless, hardware-accelerated spanning is required for playback or live TV, choose a driver/hardware path (driver span, Matrox/GXM boxes, or modern GPU multi-monitor spanning features) rather than relying on a single overlay surface.

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Member Avatar for alc6379

Are you wanting to span the video?

If so, I'm afraid that's not going to happen. Most video cards have a setting called "overlay", and it's only usable on one display at a time on most cards. There might be some cards that can do it, but they're likely to be expensive, professional-grade cards.

Member Avatar for banGerprawN

Thanks for the reply.
For anyone else who has the same question, I've done a little more research and discovered that a 'spanned' or 'stretched' desktop is not possible with the ATi line of cards, unless you are using them under Linux.
In Linux, the ATi drivers support a function called 'BigDesktop' which is just their marketing word for a stretched desktop. None of the driver's for ATi cards in Windows support this feature.
However, nVidia and Matrox cards do support this under Windows.
On nVidia cards, the function is called nView, and stretched you're 4:3 desktop to a 16:9 span across both heads of the video card, and is configurable in the nView tab of the advanced driver settings.
On Matrox cards, it is called DualView on older cards, and TripleView on the Matrox Parhelia 512 line of cards. Both options are configurable in the driver settings as well.
Thanks for the help though!

Member Avatar for Phreak

A corrcetion to your not above..

This is perfectly possible with the ATi range of cards. It is called SurroundView and you can have up to 4 monitors used at once. The chipsets this works with are basically any radeon card and either the x200 chipset or the IGP9100.

I currently use a 9700 (X850 XT PE in the post) in a shuttle XPC with the X200 X200 chipset as my home entertainment system and it works superb. Better than nView etc.

information on shuttle with surroundview can be found here:

Information on the chipset from ATi can be found here:

SurroundView

Hope this is useful

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