PCTV, Vdub, btwincap drivers -major jaggies with fast motion

[hokie91]

OK, I finally got the sound in Vdub working, now for those jaggies as I heard someone else call them...



I get this in low resolution 320x240. I can cap up to and over 640x480, but the jaggies are the same all the time. When the characters slow down, res is really great. I have tried different compression, YUY2, Huffy, Pic video, different color depths, but nothing I do seems to have an effect + or - on those jaggies. They are also always horizontal. The source that I am using is just the cable video in, but my eventual goal is my video camera. Will be easy once I get this fixed.

I have also tried increasing the buffer limits.

P4 1.6
384 MB
20GB, 7200 RPM
Win XP

Assistance greatly appreciated!

[deadpac]

What settings are you capturing with in Virtual Dub?

Are you capturing with Overlay or Preview on while you cap?

Have you tried "Swap Fields" option in Vdub while capping?

......etc

[hokie91]

I've tried preview and overlay - no difference. I never have dropped frames (actually I think I wlways lose 1 when it starts, but that's it.

I change compression which shows up in the info window while capping, but the only thing I notice is file size difference.

I have played with frame rates 15 and 29, no difference. Still get those horizontal line distortions whenthere is a lot of motion. It also seems to be worse for white colors.

It is great that we have this forum. Even though I am not an expert, I have been able to help some who are worse off than me!

[pacoreguenga]

Try "deinterlace" on your settings. Standard video signals are interlaced (except for low end tape formats) but often video gear treats every video signal as interlaced. Thus resulting in a flickering image when you record it again to video using an interlaced resolution. i.e. 720 x 480.
Computer displayable video does not need interlacing, as computer displays are uninterlaced. When you capture an interlaced signal (720 x 480) and stretch it to a lower resolution (320 x 240) you get this "jaggies".
At professional postproduction facilities we sometimes forget the interlaced nature of the signal and the pulldown issues when it comes to image compositing. When we do so, results are really tragical.
So, before doing heavy compositing jobs, we often remove pulldown (a process where a 24fps film footage gets converted to 30fps video and leaves you with 3 steady frames and 2 jittered ones and so on through all your video) to have clear frames all the way, and if the sources come with different field dominance (I swear it happens here in Mexico all the time) we have to deinterlace the signals. Not everyone uses this approach, as people is very lazy. Many just load the EDL, assemble it, and compose every layer as is, taking no care at all, which can be noticed in transitions and PIP compositions.
When we have cristal clear still images, we procceed to compositing.
This jaggies are more noticeable with high motion footage.
If this happens at pro facilities, imagine what can happen at a non- time base corrected home studio setup.

So, if your target is VCD or VHS, get rid of the jaggies from the begining by deinterlacing at capture time.

[hokie91]

Wow, that was a great response. You must do this alot. I took the informatio and did a lot of reading. And I think I know understand the problem.. However, how do you go about deinterlacing the video while capturing the video stream? Is thi sin Vdub? I looked but did not see any settings. Is it a command line type function?

My input source in an 8mm video camera, wired to a vcr input (audio and video RCA type), cable out to capture input (RG6). I'm sure you chuckle thinking about all the signal loss from all those connections. But the actual quality on my monitor is pretty good. Now to get it to a file.

[therick]

@hokie91- if you are capturing in RGB, you can enable RGB filtering under video and use any of the filters that VDub has. NOTE : any filter you use as you capture will take up more CPU power...so watch out for drops.

I would suggest you do an area based deinterlace in postprocessing (frameserving) in VDub or AVISynth.

If your source is film the best way to deinterlace is to do an inverse telecine...

[deadpac]

It is great that we have this forum. Even though I am not an expert, I have been able to help some who are worse off than me!

WHO DID YOU HELP? ................NOBODY

I was asking some general questions to try and get a better feel for what YOUR PROBLEM was.

I have no problem capturing in Virtual Dub at 352x240 -> 704x576


p4 2.53ghz, AthlonXp +2100 [1734mhz OC'd at 1839mhz], and a stock AthlonXP +2200. One water rig and two HSF'd rigs. NO PROBLEMS

Just because you weren't willing to do some trial and error runs on your DV experience don't take some little punk attitude with me.

Grow up little boy, obviously you deinterlace after the capture and when you are frameserving to your MPEG Encoder, well atleast for people like you who can't capture with RGB with filters in realtime. I could set up a dual processor AthlonMP 2000 box right now and have no problems capturing RGB 24bit at 704x576 WITH FILTERS and have no problems with.

-major jaggies with fast motion

Where in my post did I say I was worse off than you, I initially LAUGHED MY A$$ off at your post felt sorry for you so I tried to start up a two way to see what you had done, BEING VAGUE in your initial post is what causes people to ask questions, they are NOT saying they are in the same boat with you!

[therick]

whoa, you need to calm down

[hokie91]

deadpac,
I was very appreciative of your suggestions and am working through some of your ideas now. I'm sorry you misunderstood my post and apologize if you were offended.

I was actually poking fun at myself. I still have some big problems.

It is great that we have this forum. Even though I am not an expert, I have been able to help some who are worse off than me!

Meaning that thanks to you guys I am learning, and am also tyring to help others as well. Isn't it hard to believe that I (am obvious newcomer) could actually help someone else?

I have tried to help a couple people in a simialar boat with the same card and OS. Pinnacle cripples the software when you do an install with XP home and you can only cap at low res with their software. (This is my experience).

As for the incompatability of the Pinnacle drivers with Vdub, I had an error (device in use or something) with no other apps running. Then I switched to the btwincap drivers and vbud worked well (aside form the interlacing issue). I had a different question about the btwincap drivers and sent off an email to the author (also relating my other experiences)and he told me that vdub and the Pinnacle drivers were incompatabile. Since that was also my experience, I assumed that was the case. That's great if yours works.

Now I've got some more woork to do. Thanks all for your help and patients. It is greatly appreciated.

[tmcmvd]

Hmmm...now that that has been cleared up....lets see what we can do about it.

What is wrong with your picture is hard to tell by the info you supplied.

First, have you tried compressing a small part of your clip to MPEG 2 and created an SVCD with f.a. Nero ? Play this SVCD in a standalone player on a regular TV set. Maybe at your neighbours house if you don't have the equipment. Use a 480 x480 capture for this purpose, so you don't have to resize. Use TMPGenc to create the MPEG and use Nero to burn. How to do this exactly is found elsewhere on this site. Use a 1 to 5 minute clip with some panning/movement and encode CBR 2300 KBPS, not for quality, but for max DVD player compatibility.

If the clip plays normal to perfectly on a standalone DVD player (capable of SVCD, again see this site !) you really don't have a problem at all.
What you are seeing here is a simple Interlaced movie clip. Displayed on a PC monitor gives interlaced-lines...the jaggies you were talking about.

Each Frame (30 per second NTSC) consists of 2 fields who are on a tv set displayed rapidly after eachother, for the eye creating a double resolution picture. Your TV set first displays the even lines = field 1 and then the odd lines = field 2. 60 Hz is 60 times refresh per second = 60 fields = 30 frames per second (50Hz, 25 frames for PAL).

When displayed on a non interlaced monitor like your pc monitor a complete frame is created out of 2 fields. Problem is that each field is a unique moment in time, and so in moving scenes you seen 2 fields, two moments in time together in one frame. An object is displayed in position one and 1/60 second later. The faster the motion, the greater the distance between field one and two, the more jaggies you will see. When the image is not moving/panning the 2 fields are almost identical and therefore almost perfectly displayed. This is a very basic and maybe incomplete picture of what happens, search for interlacing explanation for more details.

To solve an Interlaced problem on a pc, you can either use a program to play the movie and deinterlace in real time like most commercial DVD playersoftware does. Your movie must be mainly in MPEG 2 format then.

The other option is deinterlacing the movie in virtualdub. The deinterlacing option in virtualdub is a filter (use BOB deinterlacing for best results) which you can select somewhere. Use Virtualdub's help system for info on filters. Process the output to an other file (preview in virtualdub for direct checking is possible). Now when playing in mediaplayer you won't see the lines, you will see some atifacts though becouse the 2 fields are blended together.

If your goal is an SVCD of a DVD then don't do this. When coded into MPEG 2 the problems solves itself when watched on a TV.

Now when you still have jerky playback on television after making the SVCD you might also have a field ordering problem. What happens is that some capture hard/software change the fieldorder of the movie, so the first 1/60th af a second gets swapped around with the second 1/60th of a second. So your movie continuously switches 1/60 second back in time, then 1/30th forward and 1/60 back and so on. This also displays very bad on tv , in MPEG2 it is even worse. Deinterlacing for PC playback won't work becouse the fields are blended together in the wrong order.

Field ordering problem is easy solvable with the Virtualdub Filter Swap Fields and can even be done during capture without quality loss.

Just take a small clip, don't bother about the sound and experiment as long as it takes to get it perfect. Further more read-read-read-read-read-read anything you can find on the topic...there is more to a perfect capture.

If you can capture HUFFYUV without speedproblems, hdd space problems or dropped frames, do so, it's the best quality you can get. Otherwise use MJPEG codec...with high quality settings. Use TMPG for MPEG2 encoding. Don't start messing with higher resolutions and better sound till you figure out how to solve these problems. After that you can use full PAL/NTSC resolution and PCM sound for creating a perfect X-S-VCD (30 minutes on 800 mb cd) or future DVD burning.

Hope you found this (not perfect) lecture helpfull..

For more questions...just reply.

greetz.

[Barnabas]

What you are seeing is normal. It's just interlacing. Once you convert it in TMPGenc to a VCD or SVCD and play it on your stand alone DVD player you will not see the "jaggies". You can also view your final product in Power DVD, and you will not see the "jaggies".

[hokie91]

Wow, now I really have some homework. I have been using Vdub, and the mjpeg codec (great compression) and capping at SVCD resolution so I did not have to reencode and burn with NERO. I have an APEX DVD player which recognizes the SVCD, but the videos looked the same on the PC monitor as they did on the TV. I still have much to learn, read and experiment wuth thanks to you guys.

Thanks again and I really appreciate your support.