[mythtv-users] Re: TV-Out: AITech Scan Converter vs CX2587x

[Fred]

On Mon, 2003-09-29 at 00:33, John Morris wrote:
> You don't need HDTV, but you do need component inputs on your TV.  My 32"  
> TV only accepts bare minimal 480i and the Audio Authority is putting out a
> beautiful picture, no noise from the extra A/D-D/A conversion and
> rescaling, perfectly overscanned.  I looked and looked for a similar
> product that would go from RGB to S-Video and decided the animal no longer
> exists.

Oh, cool.  I have the same setup you do: a 32" standard definition TV
with component inputs.

> In the end, even if the field sync problems are solvable I doubt truly
> perfect video playback is possible from a VGA card because I suspect the
> playback software really needs to be able to not only detect vertical
> retrace, but be able to control it. (Or twiddle the audio rate to
> perfectly line up with the video, but I have NEVER seen that capability on
> a consumer audio device.  Once they add that it is a Pro card.) Typical PC
> apps work because a computer monitor's refresh rate is so insanely high
> that it isn't as visable, but when the display is running at around the
> same framerate as the source material, unless they are EXACTLY the same
> you must have dropped/duplicated frames, and a single glitched frame is
> going to be noticable.

Thanks for the modeline.  I don't see why the software couldn't twiddle
the audio rate on the computer's sound card appropriately to match the
detected retrace.  I had an MJPEG board for a while with S-Video
output.  The playback always looked perfect framewise and the sound
coming from my sound card (to my ears) matched the video.  The problem
is that I couldn't run X on it and the MJPEG quality wasn't so hot.  I
upgraded to a DV decoder, which improved the quality but again I
couldn't run X on it.  Why don't manufacturers create a solid interface
to TV out UNLESS it has a hardware decoder in the way?  All I want is to
use my own software decoder.  Argh!

> Longterm I'm putting my hopes on the PVR-350's output for video playback
> and will use the VGA for things like MAME/MESS.  After looking at the
> specs on the chips it looks like the video encoder gets clocked from the
> mpeg decoder so sync should be perfect.

So you can't have an OSD during playback?  And you can't play back Divx
using the same path that you play back MPEG?  Sigh.

> The PVR-350 only provides S-Video and analog audio but that isn't as bad
> as it sounds.  A/B testing with a DVD between S-Video and Component
> doesn't look very different at 480i and anything recorded from TV isn't
> going to really benefit from the digital soundpath.  Guess I'll keep the
> standalone DVD player for now.  :)

Yeah, I was hoping to ditch my DVD player too but we're clearly not
there yet.

Fred