Field Order Question..

DVDTom · Post by **DVDTom** » Tue Jun 14, 2005 1:57 am

Hello All,

I want to create a DVD from older VHS tapes and also combine it with newer AVI type files from a digital camcorder. This brings up the question to me that the old analog tapes get captured with "field order B" and newer AVI files get captured with "field order A'.. Can you mix the fields with success and create a video file like this? If not, what is the workaround to create a successful DVD? I'm currently using VS7.

maddrummer3301 · Post by **maddrummer3301** » Tue Jun 14, 2005 6:38 am

I would keep both the video files separate. At lease the ones that
have different fielding order.

In the Share -> create disk module:
Start with nothing on the timeline (perfectly clean timeline).
Then import each video file separately and burn.
Keep them as separate menu items.
MD

DVDTom · Post by **DVDTom** » Tue Jun 14, 2005 7:27 am

Thanks for the response MD - you're suggestion is worth a try.

I also thought about capturing the analog video in "field order A" but I don't know if this will compromise the quality or not...it may not matter as some of this stuff is already 20 years old.

Anybody have thoughts on this?

Thanks again,

Tom

GeorgeW · Post by **GeorgeW** » Tue Jun 14, 2005 10:31 am

how do you plan to capture the older material? If it's going to be through your camcorder (as an anlog-to-dv pass through), then it should be treated as if it were DV, and would be Lower Field first.

jchunter · Post by **jchunter** » Tue Jun 14, 2005 2:13 pm

Regarding analog video capture via digital camcorder, the question is, when it converts Upper Field First to Lower Field First, does this conversion compromise picture resolution?

If Video Studio can't convert field order without reducing resolution, how can we expect a camcorder to do better?

Sombody needs to shoot some analog video of a resolution chart, capture it as UFF via an analog capture device and as LFF via a digital camdorder and compare the resolutions... (BTW, I would expect that different makes and models of camcorder would give different results.)

John

maddrummer3301 · Post by **maddrummer3301** » Tue Jun 14, 2005 6:23 pm

The camcorder passthrough isn't converting upper to lower
with respect to quality.
There's no loss in that respect.
Field Order has to be correct to define 1 complete frame.

The quality is defined by the A/D converters in the video circuitry of
the camcorder. They could be 10bit 54Mhz lower or higher.

MD

jchunter · Post by **jchunter** » Wed Jun 15, 2005 12:58 am

MD,
I've never thought more than skin deep about Field Order, so bear with me, please.

You say that changing FO while converting from an analog video stream does not reduce image quality. But it seems to me that analog to digital conversion has to happen prior to any field manipulation because the video is arriving in real time in an (analog) serial sequence and must be digitized one-"byte"-at-a-time, in order to store it in a buffer memory - first all the lines of the first field, then all the lines of the second. After a whole frame (both interlaced fields) has been received, it seems to me that that is the time to manipulate the FO. But, then, Video Studio could do exactly the same thing with its software during rendering, and even has the luxury of not having to convert in real time.

So, I still don't understand why resolution deteriorates when VS changes field order and does not deteriorate when digital camcorder does the same thing - unless VS has a bad algorithm...

John

GeorgeW · Post by **GeorgeW** » Wed Jun 15, 2005 1:25 am

Why don't we let the original poster answer the question on how the old video will be captured?

My question/comment was to say that if it was through the camcorder's analog-to-dv conversion process, that the video should be treated as lower-field first (or Field A as older Ulead software calls it). We should at least let the OP provide some more info...

DVDTom · Post by **DVDTom** » Wed Jun 15, 2005 3:02 am

Hello - thanks for all the responses.

The question as to how I captured the video is this, the analog VHS tapes were captured through an ADS Tech Instant DVD 2.0 a couple months ago. It only captures in MPEG2 via a USB port.

I shot related video on a Panasonic GS-250 last may that I want to combine with the other video and make a DVD of all the video. That I will capture via Motion Studio DV(software provided with the camcorder), also via USB as I do not have a EEE1394 card installed yet. I have been capturing in AVI files as I understand it is easier to edit than MPEG2.

My original question was prompted when, as a small test, I combined around 5 minutes of the MPEG2 and AVI clips in Share, and tried to create a video file that I would eventually burn to a DVD. I would not render teh file to MPEG2 for burning. I kept getting a field order error message until I finally deleted the older MPEG2 file. It converted and saved the AV file just fine and the test burn was great.

I have a couple of projects this summer that require the mixing of analog and DV and was wondering if there is a way to get this done?

Hope this info helps,

Tom

jchunter · Post by **jchunter** » Wed Jun 15, 2005 4:05 am

George,
Maddrummer already answered Tom's question in his first reply: "Render the different FO video in different video files and combine them only when making the DVD." The IDVD2 analog capture device yields UFF FO. The digital camcorder captures LFF.

Any further analysis of this requires an understanding of field order that few of us in this forum have. But we could all use a bit more knowledge in this area to understand the degredation that many of us have experienced when converting field order.

BTW, I do also deplore the fact that some simple questions result in far more detail than the OP asked for, but that is how we all learn...

John

I found an interesting explaination of FO at www.lurkertech.com/lg/fields/fields.html

GeorgeW · Post by **GeorgeW** » Wed Jun 15, 2005 4:21 am

John,

The OP replied to MD's response by saying he had considered capturing Field-A (Lower Field in old Ulead terms -- they have since gone away from that designation).

I then wanted to know how the analog video was going to be captured (when I posted, I did not know the IDVD was being used -- did you???).

My concern was if the analog-to-dv pass through was being used by the dv camcorder, that capturing Field-B would be BAD because the analog-to-dv would convert to Field-A. So I asked how it would be captured, and just mentioned that the dv cam pass through should be considered as field-a (lower field first).

I have the IDVD (actuallythe DVD Xpress and Instant DVD units from ADS Tech). I also have the A/V Link and several miniDV and D8 camcorders that do analog-to-dv pass through. I only wanted to find out how the OP was going to capture, so that we may offer additional help.

Because I can capture from both devices, and have mixed the captures in final DVD's. I was just curious if the captures were via analog-to-dv or not (because the OP mentioned he was considering capturing them Field A).

sjj1805 · Post by **sjj1805** » Tue Jul 19, 2005 5:49 am

"I want to create a DVD from older VHS tapes and also combine it with newer AVI type files from a digital camcorder. This brings up the question to me that the old analog tapes get captured with "field order B" and newer AVI files get captured with "field order A'.. Can you mix the fields with success and create a video file like this? If not, what is the workaround to create a successful DVD? I'm currently using VS7."

I have a project where I want to join some clips which are MPG and field order B to some AVI files which are field order A.

The MPG files are a photo slide show of my holidays generated with Pro Show Gold. The AVI is camcorder stuff of the same holiday.

I did the following tests which you may wish to try duplicating with your footage.

1. Take a small 1 minute sample of each of your two files (VHS and AVI.)

2. Create 4 MPG files as follows.

a. VHS first then AVI. Use Field Order A
b. VHS first then AVI use field order B.
c. AVI first then VHS use field order A.
d. AVI first then VHS use field order B.

I found the best results were achieved by selecting the correct field order of whichever type of file came first.

(b) and (c) produced the best results.

I might have just been lucky. However it is worth a try and will not take long for you to do a similar experiment.

My clips including lots of movement and several tall reasonably thin upright items like flag poles, plus a man walking across the scren with a "popcorn banner", also quite a bit of zooming in/out. So the clips were ideal for this experiment.