Hello,

I'll start by applauding your efforts to make an open source driver for nv 
hardware.  I imagine it is a very difficult task trying to reverse engineer 
hardware and produce something useful and featureful.

I wish to make a change to the nouveau source.  You might say I am considering 
becoming a nouveau developer.  I am one of those crazy nutters who connects my 
nvidia card directly to a television via a vga2scart cable using interlaced 
video modes.  As you are probably aware, interlaced video signals generate two 
alternating half frames or 'fields', which the interlaced display cleverly 
weaves together to form a full picture.

DVD playing software typically works by generating a progressive video stream 
by combining two consecutive (first and second) fields to produce a full 
progressive frame.  For the purpose of displaying true interlaced video (e.g. 
DVD) to an interlaced television, without using deinterlacing, the full video 
frames need to be written to the linear video buffer during the retrace after 
the second frame is drawn, so that both fields are ready to be output in 
correct order to the display.

The current proprietary drivers from nVidia synchronise buffer updates to the 
retrace after each single half frame is drawn, which for the most part is not 
satisfactory.  The symptoms of this are explained very well in this post -> 
http://www.nvnews.net/vbulletin/showthread.php?t=95836

If I understand, the nouveau drivers currently use the standard vga crtc 
registers to detect video retrace, and this results in the same behaviour.  
According to specifications I have seen from AMD, at least one Radeon series 
has registers which tell which field(first or second) is currently being drawn, 
and which field will be next.  I'm going to assume the nVidia cards have 
something similar, and I'm hoping someone may either a) know this information 
already so I can make a pretty simple change or b) suggest a way that I might 
find out this information.

Sincerely,

Jamie.

-- 
Jamie Smith <[email protected]>
_______________________________________________
Nouveau mailing list
[email protected]
http://lists.freedesktop.org/mailman/listinfo/nouveau

Reply via email to