How do I determine if interlaced video is interlaced?

[Anakunda]

Hello, I wanted to know some opinions about when do I have to use some deinterlacer and when not to for recorded TV streams or DVD video. Although the stream is always(DVD mostly) flagged as interlaced, I can see the interlacing is missing when stepping through frames of faster motion. There I don't really know if the interlacing is present and whether I can afford to omit yadif.

Is telecine possible on PAL video and if so, how do I identfy the video is telecined and not interlaced?

Thank you.

[Groucho2004]

I find this info (http://neuron2.net/faq.html) quite useful.

[manono]

Although the stream is always(DVD mostly) flagged as interlaced, I can see the interlacing is missing when stepping through frames of faster motion.
If you don't see interlacing, it's not interlaced. There's a big difference between a video being encoded as interlaced and it coming from an interlaced source. And applying a deinterlacer unnecessarliy can be very bad for progressive video.
Is telecine possible on PAL video...
No, not standard 3:2 pulldown anyway. Although I did see it once on a 20fps silent film when hard telecine was used to bring it up to 25fps.

[mbcd]

But maybe only some special parts are interlaced.

Mostly normal film-scenes are progressive, but some scenes where special effects appear are interlaced. So the movie is flagged as interlaced, but mostly progressive, thats possible too.

I have such a movie here. Its almost film, but scenes with digital effects are quite interlaced.

[Anakunda]

But maybe only some special parts are interlaced.

Mostly normal film-scenes are progressive, but some scenes where special effects appear are interlaced. So the movie is flagged as interlaced, but mostly progressive, thats possible too.

I have such a movie here. Its almost film, but scenes with digital effects are quite interlaced.

I 've seen this on DVD Stanley Kubrick A Life In Pictures, although the VOBs were flagged as progressive, some mostly B&W archive scenes had evidently the interlacing stripes. I assume this was because such document was put together from materials coming from different sources. Then question is whether to use some deinterlacer on such a DVD or not.

[Asmodian]

I think you would have to run some tests, as Manono said deinterlacing progressive material isn't good. The best way to handle it is to only deinterlace the interlaced parts. This is of course more complicated in avisynth but isn't too hard. See Trim()

If you don't mind the interlaced parts (maybe the interlacing keeps the "old video" look) you can just compress them as progressive, this also doesn't look as good as compressing them as interlaced but that isn't as good for the progressive parts.

It is very annoying that the people mastering videos often mix different kinds of video (30fps native+3:2 pulldown isn't easy also).

The answer to your original post is that the parts where you notice interlacing are interlaced and the parts where you do not aren't. How you deal with that gets complicated.

[Ghitulescu]

I 've seen this on DVD Stanley Kubrick A Life In Pictures, although the VOBs were flagged as progressive, some mostly B&W archive scenes had evidently the interlacing stripes. I assume this was because such document was put together from materials coming from different sources. Then question is whether to use some deinterlacer on such a DVD or not.

What makes you think that VOBs would have distinct interlaced/non-interlaced parts? Maybe they did the interlacing/deinterlacing step during the editing ... I've seen this quite often.