How to know if a video is interlaced?

[JLGUT]

To encode in one way or another I need to know if the video (a vob from a commercial DVD) is interlaced or not. Have you experienced any tool that will give me that information? Thank you.

[jagabo]

Open it with VirtualDubMod (not VirtualDub) and look at frames where there is motion. Do you see comb artifacts? Then it's interlaced.

Using tools that report interlaced/progressive will only tell you how the encoder was set to encode the video. Progressive frames can be encoded as if they are interlaced and interlaced frames can be encoded as if they were progressive. A commercial source would never do the latter though.

[filmboss80]

I always use GSpot to analyze the video file. At around midpoint in the right (Video) column are little indicators to tell you whether your video is progressive (PROG) or interlaced (I/L), and if it is the latter, whether it is top field first (TFF) or bottom field first (BFF).

GSpot is free, downloadable from the Tools section of this site.

[Safesurfer]

MediaInfo

[manono]

Both GSpot and MediaInfo will only tell you how it was encoded and nothing about the presence or absence of interlacing (as jagabo clearly explained). The only sure way to tell is with your eyes. This is especially important for PAL people whose movies are progressive but are almost always encoded as interlaced.

[Noahtuck]

What jagabo & manono stated, the only way to be 100% certain is with your eyes
I think a couple of us went around about this once before 8)

[JLGUT]

Thank you very much everybody. I hope that my eyes become accustomed to seeing these artifacts. I'm writing from Spain (PAL).

[AlanHK]

Thank you very much everybody. I hope that my eyes become accustomed to seeing these artifacts.

Some examples might be helpful.
See
http://www.doom9.org/ivtc-tut.htm
http://www.100fps.com/

[blackmatt]

i understand the difference between the orginal interlacing of a clip, and whether it was later interlaced in conversion to dvd mpeg2. the latter is what gspot can tell us. so if i want to deinterlace mpeg2 clips (eg to progressive avi) which are currently interlaced, then i can follow what gspot says , right?

[jagabo]

No, you ignore what Gspot tells you. Look at the video. If you see comb artifacts you probably want to deinterlace or IVTC for Divx/Xvid AVI or for upload to online video sites like Youtube. If it there are no comb artifacts treat it as progressive.