Detect Field says "Lower", but actually "Uppe

[mmtbb]

I have a ATI AIW 7500. I detect the field which says it is Lower field order. I recorded 4 hours of video only to find severe flickering in the final product. I went back and recorded in upper field, and everything is fine. What's up with that? This could make a lot of people mad if they didn't know they were recording with the wrong field, even though Ulead says it is the right field.

[LGO]

ATI AIW 7500? Are you capturing from an analog source? If so, you do need to set the field to "upper." "Lower" is used for DV source.

Yes, I had problems learning to select the correct field. Some people call it the "learning experience." I call it B.S., but I do it anyway.

[gordon_fan_24]

I don't have this device, but I assume he is talking about the automatic detection of the field order by the software. of course I could be wrong.

[gordon_fan_24]

I don't have this device, but I assume he is talking about the automatic detection of the field order by the software. of course I could be wrong.u

[gordon_fan_24]

I don't have this device, but I assume he is talking about the automatic detection of the field order by the software. of course I could be wrong.

[THoff]

I don't think anyone doubts that the correct field order is upper field first, as with most analog devices, and now you are aware of that and can avoid future fieldorder-related problems.

The question is why the order was detected incorrectly, and whether this is a repeatable problem.

It could be that the sample video that UVS captured when it determined the field order had sync problems (or an embedded Macrovision subsignal). Also, there are hardcoded field orders specific to some capture devices in an INI file I cannot currently recall, and since I'm at the office, I can't check, but this would likely override anything that UVS tried to deduce from the video capture.

[gordon_fan_24]

I don't have this device, but I assume he is talking about the automatic detection of the field order by the software. of course I could be wrong.

oops, I triple posted

[Ken Berry]

Gordon -- re the triple posting. I occasionally get a bug in this Board where it appears to have difficulty posting a message from me. Instead, I get a time-out and debug message. The first time this happened, I simply sent the message again, but then found the original post had in fact appeared. So it appears the bug report is itself buggy! But instead of keeping trying to send the message, just see if one of them comes up. And if more than one appears, then you can always delete the extras (just as you can edit after posting).

[rcurzon]

THoff, yes VS8 has a field detect capability in Options, and yes it screws up.

I have a WinFast TV2000, I wasted the first 10 days thinking that couldn't be the problem, must be something else... but it was.

[rwernyei]

I made this post awhile back, I found it in the archives:

Thanks to Jerry Jones, this reply says it all.

The concept of Field Order sometimes confuses beginners. The basics are as follows:


OHCI compliant IEEE 1394 (Firewire) PCI capture cards always specify Field Order A (Lower Field First);


USB and analog capture devices generally specify Field Order B (Upper Field First);


MPEG-2 video recorded by Panasonic, Hitachi, and Toshiba DVD camcorders and DVD player/recorders is always Field Order B (Upper Field First).


Let's assume you are using an OHCI compliant IEEE 1394 (Firewire) PCI card to capture directly to the DV .avi file format. In this circumstance, you don't have to worry about the option to choose Field Order during capture because all such Firewire cards automatically capture Field A (Lower Field First) DV .avi video. If you use an IEEE 1394 card to capture directly to the MPEG file format, then you should choose the Field A (Lower Field First) option in your MPEG capture settings. On the other hand, let's assume you're using an analog or USB capture device. In most cases, these types of devices give you the option to choose Field Order during capture. With these devices, you should first try the Field B (Upper Field First) option. Whether you are capturing, editing, or authoring, adjust your project settings to match the precise video/audio properties of your source media. This allows Ulead's Smart Render technology to work - under many circumstances - to preserve the quality of your source media.


Field Order in Ulead software hinges on the specific type of capture/acquisition device used to create your source media. Check the documentation of your capture device for details.

[daniel]

For info, I use a Pana miniDV camcorder and VS' autodetect always returns Upper field first....

Nevertheless I always capture and process lower first (FireWire) following what I read here. Looks OK, but the auto detect still makes me insecure about it... and I'd REALLY like a definitive test to check it.

[GeorgeW]

daniel, are you PAL or NTSC (out of curiosity)

[johnpr98]

Butting in

Field order with basic 1394 captured DV footage is not affected by PAL ot NTSC.
Exception, some Matrox capture cards

Regards

[GeorgeW]

Hi John

Yep, I would agree that DV via firewire is going to be Lower Field first (regardless of PAL or NTSC -- maybe an exception with some cards as you noted).

However, either I misread some recent posts (in other forums, or am showing signs of memory aging), recent threads seem to suggest that PAL DV is actually upper field, and then converted to lower field during transfer (but I don't know that to be true).

I was wondering if that might be causing the Auto-detect to see the video as Upper. Nothing concrete (and probably just a wild goose chase), I was just curious if the camcorder was a PAL cam

[johnpr98]

Hi George

Exception, some Matrox capture cards

covers any Upper Field Issues with PAL DV AFAIK

DV Footage is Lower Field, PAL or NTSC

Don't believe everything you read on the internet (Including this )

Regards