[vdr] 576i output on DVI->HDMI?

Ville Aakko ville.aakko at gmail.com
Tue Jul 15 19:34:24 CEST 2008

2008/7/15 Jukka Vaisanen <Jukka.Vaisanen at exomi.com>:
> Well the 100Hz is just a kludge to fit 576i on the HDMI signaling. My understanding is that the following happens:
> PC sends 1-1-2-2-3-3-4-4.. but the a/v receiver just ignores every other frame because it knows about the 576i kludge also.. so it is just seeing 1+2-3+4 going into the deinterlacer + scaler. The 100Hz thing is just a workaround to get enough data on the link so that the HDMI handshake will happen :P

I'd try to make a modeline:

$ gtf 720 576 50

  # 720x576 @ 50.00 Hz (GTF) hsync: 29.65 kHz; pclk: 26.57 MHz
  Modeline "720x576_50.00"  26.57  720 736 808 896  576 577 580 593
-HSync +Vsync

$ gtf 720 576 100

  # 720x576 @ 100.00 Hz (GTF) hsync: 61.10 kHz; pclk: 58.66 MHz
  Modeline "720x576_100.00"  58.66  720 760 840 960  576 577 580 611
-HSync +Vsync

(if these blow up your 50'' fullHD plasma, you're on your own - try
them at your own risk!)

I'd suspect VDR+xinelibout would not support this out of the box. You
probably need to make a script or something to change resolutions when
needed. Also, xinelibout might not like resolution switches on the
fly. But if this is the case, it could probably be worked around by
making xinelibout / X part a frontend (I believe this is possible and
a very common setup anyways), and restarting it when needed.

OTOH, I don't see much gain in doing the above compared to the
deinterlacing in software and then scaling, apart from saving some CPU
cycles. I'd doubt any external display could do a better job, though
then again, I haven't had any experience with those modern (post-4:3
CRT era TV) displays =)

 - Ville

Ville Aakko - ville.aakko at gmail.com

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