[MPlayer-users] TVout without X.

[D Richard Felker III]

On Thu, Oct 03, 2002 at 10:01:54AM +0100, Stephen Davies wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> 
> 
> On Thu, 3 Oct 2002, D Richard Felker III wrote:
> 
> > [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> > On Thu, Oct 03, 2002 at 01:02:57AM -0500, Jeremy Brenner wrote:
> > > I like the mpeg decoding, but I don't want them to skimp on the
> > > framebuffer, because you end up using 2x the processor power to play
> > > anything that isn't mpeg.  My collection consists of about 140GB of divx
> > > and 5GB of mpegs.  I love hardware decoding, but I don't wanna have to
> > > reencode all my videos on the way.  I would be happy without hw decoding
> > > if I could just find a high quality tv out paired with the ability to
> > > play without X.  That and I don't wanna replace my main vid card. 
> > 
> > Then just make an ntsc encoder (or pal if you prefer) and connect your
> > vga port to it, then set the mode timings right for ntsc (or pal).
> > It's a little work but it turned out great for me.
> 
> Hi Rich,
> 
> I guess you have an RGB->NTSC encoder.  If you have a TV with RGB-in
> (which is common in Europe) then you don't even need that - you just need
> a simple circuit to combine the syncs.
> 
> I built one - my circuit is just one transistor and a couple of passive
> components.  Yt works really well - except that:
> 
> There are not many cards still available that can generate an interlaced
> video signal at PAL/NTSC resolution.  Modern card clocks often don't go
> low enough, or interlaced output isn't supported, or accelarated video
> output (overlay or whatever) isn't supported when they are doing
> interlacing.
> 
> For instance:
>  - my Voodoo3 doesn't do interlace
>  - my laptop controller (Tosh Portege) won't do interlace
>  - my Matrox G450 won't clock low enough.  Also, no overlay
>    mode when in interlaced mode - so no XVideo, mga_vid etc.
> 
> Non-interlaced 720x288 worked OK generally but who wants to give away 1/2
> the vertical resolution?
> 
> What card exactly do you use?

I use G200, with 640x240 resolution (NTSC). Most of my movies are
320x240 or 352x240 anyway. For the higher resolution ones, -vop
halfpack reduces the quality loss by keeping all the chroma samples
and just downsampling luma.

It would also be possible to do interlaced mode, though, if I wanted
to use -vo fbdev, but unfortunately that looks horrible without vsync.
Also it's generally slow because of colorspace conversion (and because
RGB uses a LOT more bus bandwidth).

Finally, there's another possibility. On G200, overlay does not work
correctly in interlaced mode -- the picture comes out double height
because the BES only advances vertically by one unit for each line
scanned out. BUT! -- it should be possible to fix this in software, by
cleverly arranging the buffer in video memory, and changing the BES
parameters at each vsync to switch fields. Whether this is worth the
effort is another question entirely, but it should be possible.

Finally, as for allowed sync ranges, I expect the limitations are in
the drivers, not the cards. I browsed the matroxfb source not too long
ago and it seems to have some dumb arbitrary limits. For instance, I
can't get the pixel clock to go slow enough to output anything below
about 384 pixels horizontal, whereas 320 or 352 would be ideal. Of
course the obvious corollary to this discussion is that if you're
having trouble with your card not accepting the low pixel clocks you
need, just increase the horizontal resolution and use the BES to scale
up (or -- bleh! -- the software scaler).

Rich