Very bad results with PCTV and Huffyuv at 720x480

[StephLG]

Hi,

I'm testing different solutions to capture some of my NTSC Laserdiscs with the best possible quality.
I tried to capture under Premiere with a Pinnacle DV500 card but the result is a bit disappointing; the card has it's own proprietary DV codec which is very good for DV capture but results in slightly blockiness video with analog source. I would prefere capturing with the lossless HuffYUV codec but the card doesn't allow to bypass it's DV codec.
So, I tried to capture with a Pinnacle PCTV Rave TV card, under VirtualDub and with HuffYUV codec. Since I want the best quality, I set the resolution (with 'Custom format') to 720x480 YUV2 Interleaved. I manage to capture without frame dropping, disactivating 'Preview' and 'Overlay', but the result is strange. Every oblic (diagonal) line shows scaling/stepping artefacts; like if it missed some antialiasing processing. The DV capture, despite the blockiness aspect, doesn't suffer from such a scaling/stepping problem on oblic lines.
You can see a frame capture to illustrate the problem I'm talking about here:
http://mapage.noos.fr/stephane.leguevel/PCTV.jpg

Do you have an idea for the PCTV problem? Does it come from the resolution choosen? The PCTV normaly allows 640x480 at best; I have to use the 'Custom format' to achieve 720x480. Is there a resizing problem?

Help welcome.

Steph.

[StephLG]

Still no clue? :D

[Pojken Purken]

I can think of three reasons:

1) Make sure you're actually capturing both fields in each frame and not just duplicating one of the fields. Judging from the picture I think this is your problem...

2) The field order (parity) is wrong (top and bottom field switched). The following AVISynth-script will take care of that:

segmentedavisource("capture.avi")
complementparity

3) Phase-shift (bottom field of one frame is captured with top field of the next frame). Correct it with this AVISynth-script:

segmentedavisource("capture.avi")
separatefields
trim(1,0)
weave

Finally it could ofcourse be a mix of 2 and 3... ;)

Regards
PP

[StephLG]

Thank you Pojken Purken for your input.

I'll try your scripts to figure out what's going on.
By the way, do you know where, in VDub (v1.4 for instance), I can tune the fields order? Because the three possible reasons you gave me are related to problem with fields but I can't see where I can take care of it before capturing :confused: I hope something can be done BEFORE capturing and not only AFTER with some avisynth postprocessing :rolleyes:

Thanks,
Steph.

[Pojken Purken]

AFAIK all (budget) analogue capture cards unfortunately suffers from some randomness when it comes to the field order. Sometimes you get a good capture, sometimes you don't. There's no way to deal with this before the capture without spending large amounts of money on professional equipement.
Personally I find AVISynth to be an excellent tool to handle the fieldorder problem. An alternative is Donald Graft's VirtualDub filter "Smart Deinterlacer" which also have options to sort this out. Don't forget to check "Disable motion processing" in that filter if you only want to use the field manipulation tools. You can download the filter from his website http://sauron.mordor.net/dgraft/smart.html

Regards
PP

EDIT:
Just remembered that there is an option in VDub to "swap fields on input". Problem is this only take cares of field parity not phase shift. In practice it's useless though since you don't know beforehand how your capture card is going to mix the fields up.

[hs]

It definitely looks like you are capturing only one frame and duplicate that. And I also agree on all the other points :)

But another idea: did you consider to simply buy the DVDs ? I planned to convert some of my VHS-Tapes but after realizing how much time I had to invest I decided that its better to spend some money - and the quality is also way better.

I know, unfortunately thats not an option for the Star Wars-movies... :)

...HS

[chemmajik]

Also PicVideo mjpeg will allow you to change field order's around also. But I use the built in deinterlacer myself after I have created the first avi, in its final mpeg4 format conversion.

[Zhnujm]

it really looks like a field swapped picture. you can use vdubs field swap filter afterwards to correct the video during encoding.

[StephLG]

Hi guys,

Zhnujm > This is not a swaped fields problem. I tried the VirtualDub option 'swap field' but the result is the same.

I really think it is a duplicated fram issue. Since I'm not able to solve this problem and I'm not really satisfied by the picture quality of the PCTV, I've given up with this solution.
My graphic card is an old one (ATI Xpert@work bought in 1998) so I think of changing it for an Asus 8200T2 Deluxe, with video in/out. I've read it does good analog captures in full res.

Thanks for your help,
Steph.

[Zhnujm]

have you tried the "swap field option" before capturing or the "field swap filter" after capturing ? i would try the second if you havnt done before.

[StephLG]

Zhnujm > I've tried both before and after. But I think the goal of this option is to be activated/deactivated before capturing, when previewing.

[Zhnujm]

well, of course the "swap field OPTION" can only be used before capturing, but the "field swap FILTER" is for use after capturing during compression to whatever format you like.

[StephLG]

Sorry Zhnujm, I had read your post too fast.
Nevertheless, I had already tried the 'swap fields' filter without success.

I bought the Asus 8200 Ti Deluxe today; I'll see how it behaves.

Thanx,
Steph.

[therick]

@StephLG - Only one thing to do. Get rid of the Pinnacle. I had a Hauppage WinTV-Go and upgraded to the Pinnacle PCTV for the S-Video input just to do my Star Wars LDs. Bad move. Here are some of my pictures:

www.clemson.edu/~rlrobbi

I had the same problem with the video looking like the fields were swapped. Swapped the fields. No good. Used AVISynth and Decomb. Still awful. I went back to the Win-TV Go...great quality. The Pinnacle gave me awful color, washed out and grainy captures...it just sucked all around. The Win-TV Go looks better through the COMPOSITE than the Pinnacle did through the S-Video (this goes for my sat captures also). So I would say that it is most definitely the shitty Pinnacle card...take it from someone who wasted hours and hours with it....

[StephLG]

Hi all,

just a few words to say that the results got better with the Asus 8200 card.
I didn't manage to obtain satisfying results with VirtualDub; there are still some strange stepping problems (although less than with the PCTV Rave). I finally used AVI IO v0.3.11 and got something like this:
http://mapage.noos.fr/stephane.leguevel/Asus-8200.jpg

I find this a lot more pleasant. It is a HuffYUV capture, after some AviSynth processing (IVTC, Crop and BicubicResize to obtain an anamorphic video format).
The color still needs improvment but I didn't work on that (not yet).

[Vanos_b]

Did you tried to use RGB24 instead of YUV2 Interleaved? It works for me (I have a Pinnacle PCTV too). Of course you'll have a higher CPU load.
Regards.

[therick]

@Vanos_b - what is your processor speed and what resolution are you capturing?