What tool to use to determine field order?

[dinkob]

If I were to encode something to DVD or SVCD using Interlace encode mode, and if the source is interlaced, how to determine whether I should set Top Field First A or Bottom Field First B (source video setting in tmpgenc).

I had recently encountered a problem with this where I had to encode two separate files in a different way and then they would play properly (even joined) in home DVD player.

Thanks for any input.

d

[daamon]

Hi dinkob,

If your source is from a miniDV cam, it's usually lower field (B field) first.

Also, TMPGEnc should be able to figure out the field order of an interlaced source and so it'll default to the correct one.

As for a tool to use to identify the field order - I'm not aware of one, but that doesn't mean there's not one out there...

[mike909]

I too, would like to know if there is a tool to identify the field order of files. I know DV footage is usually lower, but I am often working with all different kinds of footage and would like an easy way to see what field order I should use. When I export as mpeg2 for dvd production, I often have mixed footage and the final result looks messed up for some of the footage and find for others. My solution would be to convert all files to the same field order, but I can't figure out what that should be.

[dphirschler]

Here's my method.

Load the video into Virtual Dub. Add the deinterlace filter and set it to unfold fields side-by-side. Step through the video and watch the motion. A scene change is easiest if you can find one. If you see the left side change first then it is TFF, otherwise it is BFF.


Darryl

[mike909]

yea, another 'long way' of determining it, is to load it into tmpgenc (thought this doesn't allways work correctly); also, tmpgenc express identifies a different field order (for me anyways) than pre-express versions do (specifically 2.5). I'm surprised that with all the problems that end up being the result of wrong field order selection, there isn't a tool for identification.