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Old 3rd March 2006, 05:30   #21  |  Link
jmac698
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resolution in luma vs chroma

Have we been talking about different things all this time? When I said my resolution was 3.75MHz I meant the chroma part only. the luma part is 6MHz, and therefore, my C4All technique has chroma also at 6MHz.
The smearing I now believe is an inherent function of svideo, because the chroma information is lowpass filtered relative to the luma.

I posted some new tests, which show this smearing. You can't read the colored text in svideo, but you can in component.

But what is really going on here is quite complicated;
1) The chroma offset of YV12 sampling adds 1 pixel of blurriness around a color boundary,
2) The DVD player is upsampling the YV12 chroma with bicubic or higher order interpolation,
3) Svideo itself is filtering the resulting chroma

To really know my final chroma resolution measurement I think I need a controlled source like a video card output, with no chroma upsampling.
Anyhow, I'm quite convinced by now it gives at least 2x better quality. Aren't you?
To finish this off, I only have to workout the calibration issues, that are giving that stupid color cast.
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Old 7th March 2006, 17:25   #22  |  Link
Qjimbo
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Wow pretty inventive! But surely you're limited to what things you can do this with? You wouldn't be able to do it from a live HD source because you have to cap it several times...

What'd be cooler is if someone found a way of putting RGB data straight into the Theater 550
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Old 7th March 2006, 20:24   #23  |  Link
jmac698
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rgb, restriction to live source

Thank you Most people think it's a waste of time, but I think it's neat, and I'm doing it for fun.
Actually, I can record RGB, in fact even VGA output at the proper refresh rate could be capped. Also old systems like Amiga 2000 could be capped.
With TVTool, most Nvidia cards can output component or RGB data, with a special cable, also the Hollywood Plus can output component or RGB (I have the cable and have tested this). So I can test this next.
You can get even higher rez by capping with PAL-M, in black and white it's like NTSC but with 768 pixels by default.
As for live sources - yes that is a problem, but something good could be done with 2 or 3 capscards at the same time. A single PVR350 has dualtuner, this could be used. I would cap the Svideo and P+Pr signal, as your eye is more sensitive to color rez here. They could be merged in higher quality.
Potentially you could write a program to switch video inputs every field, because of 3:2 pulldown you could completely cap live, because the fields repeat and you would switch inputs.
Almost anything is possible Wow, you just gave me a bunch of ideas, thanks

Last edited by jmac698; 7th March 2006 at 20:28.
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Old 7th March 2006, 21:41   #24  |  Link
Qjimbo
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Quote:
Actually, I can record RGB, in fact even VGA output at the proper refresh rate could be capped.
What card are you using? I know some cards like the Sweetspot can do RGB, but they're software only (and pricey). I reckon my Theater 550 card it must break down the composite/svideo into rgb at some point, though I could be wrong. If I'm right however all would be required would be to solder wires onto the board at this point in the circuit. The hard part is identifying where it does this exactly (if at all).
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Old 7th March 2006, 22:01   #25  |  Link
jmac698
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no modz!

Nope! Any card can record component, or RGB, with no hardware mods. But you do need a special cable.
Same as my component for all technique, just connect G+B together, connect to the svideo in (luma pins), cap. Connect G+R together, connect to the svideo in (luma pins), cap.
Then connect G by itself, cap.
Then a simple script will subtract (G+B)-G=B, (G+R)-G=R, and you have G. G must always be connected, because it has "sync pulses", and without those detected, the capcard will not activate.
There are no limits to recording anything, as long as you have a sync pulse with suitable timing that can be recognized in Pal or NTSC timings. VGA has separate Hsync and Vsyn pulse you could wire together, with a color, and there's a chance the capcard will pick it up.
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Old 7th March 2006, 23:12   #26  |  Link
Qjimbo
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Oh I see what you mean, but it's hardly smooth because it has the same problems as your first method. I have a few games consoles that output as RGB, I was thinking of capping those, which wouldn't be possible using your multipass method...

One thing I did notice a while ago on the datasheet for the BT878A card was that it had 4 composite inputs, check it out here. Such a thing might be usable for your Component method, it's odd that these extra connectors aren't used anywhere.

EDIT: Seems that that is quite a high spec. chip, not your average BT chip. But anyway...

Last edited by Qjimbo; 7th March 2006 at 23:39.
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Old 8th March 2006, 00:26   #27  |  Link
jmac698
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live recording problem

If it were a repeatable thing, like an old Amiga demo, or the "attract mode" loop at the start of a game, then yes, but I see the real need for live capture here.
I thought of this before; what you need are 3 devices, like VCR, dvd recorder, and computer, or dual tuner cap card and VCR, etc. There is one problem still, the Y needs to be replicated 3 times; you can use a distribution amplifier for this, it only need to be 1 to 3 way composite. Then you can connect all combinations at the same time. I'm worried about how stable the VCR is, though. The dvd recorder can essentially replace one computer with a capcard.
Btw, you can also use two satellite boxes tuned to the same channel - what you get is "collaborative recording", where one person records part of it, someone another part, this can be live, but then you have to share files.
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Old 11th March 2006, 21:02   #28  |  Link
jmac698
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cool discovery

It turns you can view my vyu mode live, on your TV right now, by changing one setting. Check your hidef source that has HDMI/DVI output. See if it has a setting to output RGB or YCC 4:4:4. Change RGB to YCC, and it's the same as my vyu, in other words the screen will look very purple. That's because R and B averages around 128 now.
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Old 10th June 2006, 04:12   #29  |  Link
jmac698
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bump

Bumping this because someone asked if it were possible to record component video.
As for news, nothing has changed due to the inability of avisynth to return the value of a pixel in script.
If the pixelinfo filter is ever finished, it will be possible to create a semi-automatic version of the "component4all" technique, in terms of the calibration proceedure.
Until then, again a summary:
It is possible for ANY capture card to record component video. The benefits of this is at least 1.6 better looking picture, as compared to an svideo picture, this was tested scientifically.
There is a disadvantage in that you need to record the exact video 3 times in a row; each pass is one color of the component.
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Old 5th September 2007, 01:30   #30  |  Link
jmac698
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Just like to mention I wrote a real avisynth compiled filter for this. Might play again with it some day just for fun. I've also captured 480p, though there is a slight problem with some pixels cutoff horizontally. If capturing a pulled down movie, this effect can be compensated exactly, and for general video, you might have to fill in missing strip with standard def image...

Last edited by jmac698; 5th September 2007 at 01:46.
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Old 11th September 2007, 14:02   #31  |  Link
2Bdecided
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Wouldn't the ability to capture 480p depend entirely on your card's ability to find the half-width H-sync in a 480p signal? Some may, and transform two input 480p lines onto one output 480i line - but don't some just give up?

Also, given that 480p requires twice the bandwidth, and a 480i card doesn't have it, you're effectively sampling at 360 pixels per original line, rather than 720.

Still an interesting technique, and good to play around with for 480i/576i component. However, for real time capture, rather than buying 3 PCs and 3 standard capture cards, it would be cheaper to buy one PC and a component capture card.

Cheers,
David.
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