Field order issue -

[Spektre]

I have always captured with a Hauppauge device which was known for setting its field order flag wrong. Rendering DVDs without correcting for this in the authoring process caused jerky video.

I now have a brand new workflow. ATI 600 USB device capturing to AVI with virtualdub.

I pull the resulting AVI into Sony Vegas for editing and encoding to MPG, and finally authored with Sony Architect. I have verified the Sony chain is all set to BFF.

Sure enough, the video looks jerky with what I suspect is a field problem.

What's the virtualdub's default capturing order? Is there anyway teo verify whast order I have in the avi before encoding?

Thanks

[jagabo]

VirtualDub doesn't control the field order. The capture device (or driver) does. You can verify the field order in VirtualDub. Add the Bob Doubler filter, set to TFF or BFF. If motion is jerky as you step through frames you guessed wrong.

[Spektre]

Many thanks for the method of checking jagabo and let me say...dude (or dudette) you are awesome. I do try to give back here occasionally when I find a topic I am knowledgeable on, but you have been a fountain of help on this project.

So...I guessed wrong and the video captured from the ATI USB 600 is TFF.

Any ideas on how to fix this without recapturing? (I don't have access to the source tape any more.)

I am going to try setting my Vegas project up as a TFF project and then ask it to render BFF and see if that works.

Thanks again.

[Spektre]

Telling Vegas the source file was TFF and that I wanted to render BFF did nothing, the resulting DVD still looks like it was shot in an earth quake. Will have to try some more tomorrow.

[hech54]

I have always captured with a Hauppauge device which was known for setting its field order flag wrong

Never had that problem. I own two Hauppauge devices.

[Spektre]

The venerable PVR-150 was known to set the field flag wrong. I used to burn the compliant PG2 streams with Nero and always had to reverse the field ordering.

As to the original problem, it appears if I set up the entire Sony workflow to be TFF (UFF) I can use the captured footage without judder. I can do some more studying to find out why Vegas is not converting the field order when it is being set correctly manually later, but at least I think I can use the captured video I have.

[jagabo]

it appears if I set up the entire Sony workflow to be TFF (UFF) I can use the captured footage without judder.

Yes, generally, there's no need to change the field order. Tell Vegas your video is TFF, encode TFF.

I can do some more studying to find out why Vegas is not converting the field order when it is being set correctly manually later, but at least I think I can use the captured video I have.

I don't know Vegas but are you sure that setting changes the video's field order, not just the flagged field order?

There are two ways you can convert the video's field order. You can shift the frame up or down by one scan line. Or you can separate the fields, throw the first field away (or insert an extra field at the start), then recombine the fields into frames.

An interlaced analog signal is a series of alternating top and bottom fields. A capture device can start with a top field, then add the next field (a bottom field) to complete the frame, creating a top field first video. Or it can start with a bottom field, then add the next field (a top field), creating bottom field first frames. At playback the player has to know which of the two fields to display first, hence the field order flag.

[LightWeightProducer]

The venerable PVR-150 was known to set the field flag wrong..

Interesting comment. I have a PVR-150 and have recorded more hours [PAL] than I care to recall using it and never saw the indicated field order out of the card be anything but how it had encoded the video, TFF.

[The_Doman]

The venerable PVR-150 was known to set the field flag wrong..

Interesting comment. I have a PVR-150 and have recorded more hours [PAL] than I care to recall using it and never saw the indicated field order out of the card be anything but how it had encoded the video, TFF.

Same here, sure the card had it's issue's but with my PVR 150's (PAL) i never had problems with the field order in my recordings. Burning the recorded MPEG2 streams directly to DVD always working fine without playback problems

[fvisagie]

Any ideas on how to fix this without recapturing? (I don't have access to the source tape any more.)

When I had this problem in the past (MPGs with incorrect field order issue), Restream fixed them for me. I only needed to redo authoring, i.e. not even re-encoding was needed.

I can't remember for certain though whether my problem was due to incorrect field order, or incorrectly flagged field order as mentioned by jagabo. However, I thought I'd mention this experience in case it's of some use to you.

Cheers,
Francois