ATI AIW Radeon capture field reversal

johnmeyer wrote on 3/5/2005, 6:27 PM
Sometimes I want to capture analog video through my ATI All-in-Wonder Radeon 8500 DV card (when my DV camera is tied up, for instance).
If I do this using ATI's software (that came with the card, updated to latest version) or with VirtualDub, the fields on the captured video are reversed. This is true whether I use the Huffyuv codec or the standalone MainConcept DV codec which I purchased a long time ago.

I have tried selecting the field reversal switch in the Mainconcept encoder setup. The video still "judders" when played back from the Vegas timeline. I have tried using the VirtualDub "swap fields" switch. No luck. I tried the "reverse field dominance" filter for Virtualdub. No luck there either.

I tried capturing directly into Vegas, but that has more problems than I can fit into this post.

I have read the capture guides at doom9.org, videohelp.com, and lordsmurf.com (now called digitalfaq.com), but no luck.

Ultimately, I can still use the captures by selecting the captured events, changing lower to upper field, and then rendering, but this means I have to render every frame of every capture, a real time-waster.

Anyone have any ideas (other than trashing the ATI card)?

Comments

JohnnyRoy wrote on 3/5/2005, 6:42 PM
> Anyone have any ideas (other than trashing the ATI card)?

Actually no. I believe the field order is determine by the capture device. Your card just happens to capture upper filed first (which is very common for analog capture devices) That’s just how the hardware works. If I remember correctly my old Pinnacle DC10+ was the same way. (back then we use to complain our new DV cameras are capturing in the wrong order ;-))

As long as you maintain field order it won’t matter. That means creating a new MPEG rendering template with Upper Field First.

I have an ADS Pyro A/V Link (around $150) and it captures analog with a DV codec lower field first so you can mix analog and digital on the same timeline without any problems.

I could be wrong, but I think the field order is burned into the capture hardware.

~jr
johnmeyer wrote on 3/5/2005, 6:52 PM
As long as you maintain field order it won’t matter. That means creating a new MPEG rendering template with Upper Field First.

Interesting idea. So just render and burn it to a DVD as is?

I'll try that and see what happens. None of this is destined to go back out to DV tape.
TheHappyFriar wrote on 3/5/2005, 7:20 PM
I have an ATI AIW 9600 Pro. It does the same thing for AVI capture (just an FYI-mpeg capture does lower field first).

I just made a special template for ATI AVI projects/rendering. I capture at 704x480, do you (that's the max AVI size I get. Mpeg-2 gets 720x480 no problem)? So, I made a project that is 704x480, upper field first & have no problems (it's called NTSC ATI template). I also have a mpeg-2 encode setting that does the same thing (renders at 704x480 upper field, which is still in the DVD specs).

I found this out last year when I tried to mix DV with the ATI-AIW footage. :) I ended up re-rendering the DV to upper field first. :)
johnmeyer wrote on 3/5/2005, 7:49 PM
I just made a special template for ATI AVI projects/rendering.

That's what I'm doing to. It means, of course, that you can't use the external monitor for previewing, unless you first render, or unless you just ignore the "judder" from the wrong field dominance. Also, it means that every frame must be rendered, even in a cuts-only project. Of course, Sony's codec is excellent, so I am not worried about quality, just about the needless waste of time.

I was hoping there was some way to accomplish the field reversal during capture.
johnmeyer wrote on 3/5/2005, 9:03 PM
Well, I just created several test DVDs. I tried rendering to MPEG-2 with the MPEG-2 template set to lower field first, and the upper field first. I put these into DVDA. DVDA insisted on re-rendering the lower field first MPEG-2 (that's right the lower field first), because it sensed that things were screwed up. I burned and played on my set top DVD player, and the video looked terrible. The field reversal was still there.

I then went back and set the EVENT's properties to upper field first and rendered with the normal DVDA NTSC template (lower field first). I burned the result, and this played just fine.

The problem is, I think, that while it may be true that the DVD player doesn't care about field dominance, you have to feed the fields to the encoder in the right order. Therefore you HAVE to specify upper field first for the event. The field specification in the rendering template doesn't accomplish the same thing.

Thus, I am back to exactly where I started, namely having to render every second of video captured this way, unless I can figure out how to do the field reversal by diddling with the capture driver somehow.
TheHappyFriar wrote on 3/5/2005, 9:55 PM
Yes, the event DOES need the same field order as the render. That's why I render my ATI captured video in upper field.

I don't have DVDA, but does it have a fit about mixing media of different fields in a DVD? I use TMPGenc DVD right now & I've mixed upper & lower no problem.

When I've render "cuts only" from footage capture from my ATI (using Huffy, 704x480, upper, 29.97) to mpeg-2 I've had RT or better then RT speeds (AMD 64 3000+). BUT, I need to keep the settings the same or else it doesn't work.

I also get good preview speeds with project settings matching hte clip settings, but I don't preview on a monitor.