How to interlace an progressive video

[swtrse]

Maybe it's a stupid question but I found tonns of deinterlacing howtwos but no interlacing howtwo.

Can someone give me an Avisynthscript that does interlacing an progresive Video?

I want to do this because I am tryint to RIP an movie to my IPAQ as you can imagine size is important.
My idea is that an interlaced movie needs less space than an progressive and you can use an lower fps rate what should save extra space. Thats what I think.

[kingmob]

There are two positives for interlacing as far as i know it. The first is, that it is easier/cheaper for a camera to obtain a decent fps this way, one full frame needs a more expensive CCD than 2 fields.
The next advantage is that movements probably will look a bit smoother with interlaced footage on a TV.
But if you have progressive footage, neither of these apply and so you'd not win anything by interlacing. So in short, i would not do it.

If you still want to do it, you'd have to double the framerate and create fields out of the frames. This would give you duplicate fields unless you interpolate between frames. The only advantage i'd see in this, is that possibly you can get away with a lower bitrate, But i do not know that for sure.

ps. I'm far from an expert, but i want to contribute ;). All of this i just made up.

[Boulder]

Originally posted by swtrse
My idea is that an interlaced movie needs less space than an progressive and you can use an lower fps rate what should save extra space.

It's the other way around. Interlaced material requires more bits for the same quality than progressive.

[swtrse]

Originally posted by kingmob
There are two positives for interlacing as far as i know it. The first is, that it is easier/cheaper for a camera to obtain a decent fps this way, one full frame needs a more expensive CCD than 2 fields.
The next advantage is that movements probably will look a bit smoother with interlaced footage on a TV.
But if you have progressive footage, neither of these apply and so you'd not win anything by interlacing. So in short, i would not do it.

If you still want to do it, you'd have to double the framerate and create fields out of the frames. This would give you duplicate fields unless you interpolate between frames. The only advantage i'd see in this, is that possibly you can get away with a lower bitrate, But i do not know that for sure.

ps. I'm far from an expert, but i want to contribute ;). All of this i just made up.

So what I have to do is.
1) create Fields (2 movies with half the height of the original)
2) merge the 2 Fields to one movie File.

The question is how to tell the codec that the merged movie file is interlaced?

@Boulder: Maybe, but I think that an progessive movie (for Example 800x600 24fps) is bigger than an interlaced movie (800x300 24fps) or I missunderstood something about interlaced.

I'll will try it for sure so I will also post the results and maybe an guide to make real small ipaq movies ^^.

[Kika]

This might be the easiest Way to do this, but it's pointless:

separatefields().Trim(1,0).Weave()

[scharfis_brain]

@swtrse: if you want to save space and intend to playback the voideo on an portable decive, interlacing is EVIL!

first, we need some parameters of your source video:
framerate, size (pixels), duration

and your desired destimation format...

[swtrse]

Destination Format:
* wmv
* max. Resolution of the Screen is 320x240.

Source Format:
*720x576
*25fps progressive
*High-Quality Audiostream

[Mug Funky]

hmm... best option there is just to scale it down or deinterlace first. assuming you're using NTSC, 240 = half of 480, so your fields will be blended together. this gives kinda excessive motion-blur and maybe ghosting (if shutter is less than 1/60), but WMV will probably love it. either than or deinterlace by field-discarding, giving you 720x240 which can be resized easily to 320x240.

interlacing in 320x240 would make a big mess, especially considering what WMV does to interlace (interlace + non-interlace aware inloop filter = crap, inflated filesize).

does the ipaq play anything other than WMV? it's an ugly format, but ii guess it's your choice :)

[stickboy]

Originally posted by Kika
This might be the easiest Way to do this, but it's pointless:

separatefields().Trim(1,0).Weave() LOL. :p

[swtrse]

Originally posted by Mug Funky
hmm... best option there is just to scale it down or deinterlace first. assuming you're using NTSC, 240 = half of 480, so your fields will be blended together. this gives kinda excessive motion-blur and maybe ghosting (if shutter is less than 1/60), but WMV will probably love it. either than or deinterlace by field-discarding, giving you 720x240 which can be resized easily to 320x240.

interlacing in 320x240 would make a big mess, especially considering what WMV does to interlace (interlace + non-interlace aware inloop filter = crap, inflated filesize).

does the ipaq play anything other than WMV? it's an ugly format, but ii guess it's your choice :)

WMV ist the only Format that is supported by my ipaq

[kingmob]

I have a player which plays divx, xvid and mpeg1/2 also on my ipaq. It's called PocketMVP. There's also a mpegplayer called PocketTV.

[swtrse]

thanks that player is relay great ^^.

So what would be the best format for my problem?

divx, ogm, ...?
Has anyone ever tryed it?

[kingmob]

I use xvid, it's the best at such low bitrates imo.

[babyray-uk]

Hi Guys

You should take a look at

http://betaplayer.corecodec.org/

Supports B-Frames as well...

Speak Soon

BabyRaY