AVI and interleave

Paul Masters wrote on 4/5/2008, 12:02 PM
I am trying to find out who is doing what with AVI and interleave.
I created 3 sample outputs of the same project in Boris RED. 1 upper, 1 lower, 1 none.

When I import them to Vegas the media properties all say the same - Field order: Upper field first.

When I import them back into RED, the field order appears to depend on the setting in the Preferences Input Interpret field order.

I have found some tools on the WEB to look at video files and display information, but none appear to indicate the field order.

I am doing this because I am having problems with a RED project creating some moving text for a DVD menu. The text has ‘lines' in it like the interleave screen door effect while the text is moving. Therefore, I am trying to find out what is causing that as I thought I exported it as progressive but I can't tell for sure.

Another interesting thing, if I change the media properties in Vegas for the clips it appears to make no difference for the upper and lower field first clips. Howveer, if I set the clip that I think is progressive to none, then the interleave effect dissapears.

I am losing what little mind I have left! <g>. Is there a way to tell the field order in an AVI file? And if so, why doesn't Vegas report it?

To add to the confusion, the field order in the project propertise is upper. I rendered with none. The DVD title has the lines, while the Vegas preview doesn't.

Thanks for any pointers.

Paul Masters

Comments

johnmeyer wrote on 4/5/2008, 2:20 PM
Determining field order is simple to do using a trick in the shareware program TMPGEnc. But, I don't know how to do it in Vegas.
John_Cline wrote on 4/5/2008, 2:22 PM
You'd think there would be some sort of simple freeware utility to do this, but there isn't.
johnmeyer wrote on 4/5/2008, 3:07 PM
If you want to download TMPGEnc, I think it still lets you try portions of the program without buying it. For use as a field order detector, I'm sure that any trial version will be perfectly adequate.

Ah, I thought I had described in another thread how to do this. Here it is:

Jerky SD



fausseplanete wrote on 4/6/2008, 2:59 AM
GSpot gives field order and lots more info. Freeware from www.headbands.com/gspot.
johnmeyer wrote on 4/6/2008, 9:13 AM
My bad eyes completely overlooked that little icon (it's in the middle, just below the "pics, frames, fields" boxes).
Paul Masters wrote on 4/6/2008, 10:57 AM
Found GSpot. It gives field order for MPEG but not AVI.

Tried TMPGEnc. It shows the 'upper' clip as upper, the 'lower' clip as lower and the progressive clip as lower.

(Well... It at least shows something. <g>)

Thanks for the suggestions.

Paul Masters
Paul Masters wrote on 4/6/2008, 11:50 AM
I spent a number of hours with Vegas finding out the following. It would have been nice if Sony had told me when I asked them (see another thread of mine here) or if it was in the documentation.

The field order in the media properties appears to have no effect. That is, the clip that is supposted to be progressive previewes with out the interlace effect regardless of the media property field order setting.

Thinking that Vegas would write and read the information correctly, I ensured that the field order in each of the three clips was as I thought it was supposed to be and rendered using AVI - uncompressed with the 'correct' field order in the render template. Importing those back to the time line, the properties were as the original clips had been - all showed upper field.

I did a number of other tests with various settings. Unfortunately I did not write down all the iteratins and the results and, of course, now I can't remember exactly what I did - one of these days I may learn not to do that. <g>

However, in general I found:

In the Project properties, the Deinterlace option only has effect if the field order is set to none.

The render templates seem to set the field order as they wish, which is likely a good thing. But the AVI type with the uncompressed template appears to set field order the same as the Project properties.

Most importantely, if the Project properties field order is set to none and deinterlace is set to interpolate, none of the original clips show interlace artifacts when played back in the time line.

I took the lower clip (with Properties as none and interpolate) and rendered it with AVI - uncompressed once as field none and again as field lower. Importing them back to Vegas, both clips had media properties of upper (nothing new there <g>) and both played back with out the interleave artifacts. Of course I realize that one is procressive and the other is interleaved, but I couldn't tell the difference in the preview window.

However, compairing those two clips, I noticed that while they were the same lentgh, the motion was off by about 1/2 frame. I checked each with the 3 original clips and found that the one rendered as interlaced was the one that was off,

All this is still confusing to me. I am from a world of software where things (settings) work as you set them, not as they feel like it. I realize that from others comments in this thread and another of mine on simular lines, that things could get really messed up if some settings were wrong, but I expect them to do what I tell them to do, right or wrong.

Anyway, I would be interested in anyones comments on my findings. Perhaps I still don't understand something.

One question: Using this 'trick' am I loseing resolution? I can't tell from the preview screen.

Thanks for any remarks.

Paul Masters
John_Cline wrote on 4/6/2008, 12:09 PM
"Found GSpot. It gives field order for MPEG but not AVI."

That's because an MPEG file has a flag for field order, but there is no flag in an .AVI file to tell its field order. GSpot is just reading the flag on the MPEG file, not actually testing the video like TMPGEnc.
johnmeyer wrote on 4/6/2008, 2:05 PM
But the AVI type with the uncompressed template appears to set field order the same as the Project properties.

This probably has no bearing on your problem, but just in case it does, I found that when you choose the uncompressed template for rendering, the original video is passed through without the need to set anything. In other words, you don't need to fool with presets. I used this in my deshaker script to get around the limitations in the Vegas scripting language where it doesn't let you get or set the presets.

However, I also found a bug (or at least that is how I classified it) relating to using uncompressed with PAL footage. What I found is that PAL uncompressed widescreen changes PAR to 4:3, and more importantly for this topic, PAL uncompressed always reverses fields!