Re: [libdv-dev] RE: Streaming DV

[James B. <ja...@ex...>]

Arne Schirmacher wrote:
> 
> Best of breed in the Windows world: The Microsoft DV codec does easily 30 fps
> fullscreen on my AMD 333 MHz with a Matrox Millenium card.
> 
> The trick with most Windows graphics software is that they use the hardware
> features of the graphics card, whereas on Linux it is all done in software. A
> very expensive operation is the YUV to RGB conversion and scaling. Many cards
> can do this in hardware -- write the YUV (or whatever other format) to the
> card's memory, setup source and destination rects in some registers and zap!
> RGB data is just there. I wrote a Quicktime codec for an obscure Macintosh PCI
> graphics card five years ago and using the hardware features I could do 25 fps
> fullscreen PAL videos on a PowerMac 100 MHz (compareable to a 100-150 MHz
> Pentium).
> 
> So to get decent codec performance somebody needs to look into how hardware
> acceleration is done under Linux / XFree86.

I'm running libdv on an Intel PII/300, and have got reasonable
performance (30fps) running with custom backends for placement and
display.  Displaying a 16-bit X visual is pretty painful; the only way I
can get 30fps is by shrinking the image to half-size; 360x240 for NTSC. 
Using fbcon with a 800x600 screen works ok, but I had trouble getting
multimon working with anything except Matrox cards.  What I'm currently
using is a 3dfx Voodoo 1 card - this gets 30fps when displaying
monochrome; I use Glide to download the picture as a series of textures
then draw some big texture-mapped triangles that cover the screen. 
Sounds weird but works ok.

-- 
James Bowman
ja...@ex...