16x9 video possible?

[dphirschler]

If I make a 16x9 anamorphic DVD, does it have to be film or can it be video (ie interlaced)? This question came to my mind when I was considering the scaling that a player does for 4:3 TVs. How would a player go about scaling a 16x9 interlaced video for a 4:3 TV?


Darryl

[edDV]

"If I make a 16x9 anamorphic DVD, does it have to be film or can it be video (ie interlaced)? "

can be anything, even a cropped jpeg

"How would a player go about scaling a 16x9 interlaced video for a 4:3 TV? "

it can

1. chop the sides
2. pan and scan (under authoring control)
3. squeeze/squash horizontally

what was your question?

PS: and of course you can letterbox it.

[vhelp]

@ dphirschler (darryl)

I do this all the time w/ my CAM footage.

You can do it 2.35 or 1.85 AR's. I've ben exploring the 1.85 AR's
because the movie, "Deuce Bigalow" is in 1.85 and I was trying to
figure how to obtain this same AR w/ my home footage. It was very
triky to do and fiture out. But, I did get it. (where are my notes)
Anyways.

Yes, as was stated above, you can do it w/ *ANY* video source.
The trick (though I'm sure you know) is in the crop (hehe)

Anyways. Good question.
-vhelp

[guns1inger]

You do risk quality loss, as to creat anamorphic from a non-anamorphic source requires first cropping the footage, then resizing it vertically. If your source footage is non-anamorphic you will get the same outcome, with less rick of quality loss, but a simple letterbox matte.

[alsyed]

i wouldn't even bother with going anamorphic if your source frame size isn't bigger than 720 x 480/576. Because in the end, you are doing 2 resizes - 1 during the encode, and 1 extra while watching it. I live in pal land, so an anamorphic dvd here would be on a 1:1 scale 1024 x 576. The letter box matte is the best solution for non anamorphic content. and interestingly, is the solution most handy cams use too to fool you into thinking you can shoot 16:9.

[edDV]

If you shrink vertically you can loose that amount of vertical resolution quality. Nice thing about DTV is the full vertical resolution is used when the image is letterboxed. The TV scans the same v resolution to a tighter screen area for 4:3 HDTV sets.

Aspect ratio adjustment using pan and scan usually only requires horizontal pans at the same vertical resolution. Only a few difficult scenes need to be zoomed.

As a TV geek, I associate the term "anamorphic" with optical lens corrections done in telecine transfers. I know computer geeks apply the term to aspect ratios. You should see those spherical distortions off a real anamorphic lens.

[dphirschler]

Woops, I think you guys misunderstood the question. We all know when a progressive source is anamorphic, it gets scaled on a 4x3 TV. The player simply resamples the image and adds 60 lines at the top and bottom. Some players do it better than others.

But what if the source is not progressive? Simply scaling it will introduce all kinds of ugly artifacts as the interlaced lines get partially blended together. Does the player first do a bob deinterlace, scale it, and then a weave? Or is it simply illegal to make interlaced 16x9 DVDs?


Darryl

[vhelp]

Then the question is, which AR are you refering to ??

* 1.778 - - 16x9
* 1.85
* 2.35

The 1.85 and 2.35 are the ones that are usually Anamorphic'ized.
These two are the ones that require a crop and resize during a
video conversion.

But, a true 16x9 (1.778 AR) would not. At least not from a
4:3 AR footage.

If I wanted to take my TRV22 cam's footage from tape (interlaced)
and make it 16x9 (1.778 AR) from it's 4:3 mode footage (I don't
use the fake 16x9 mode in my footaging) I would simply just
crop off 60 x 60 - - but that might lead to issues on some
situations like frameserving maybe. I do this all under TMPG
instead, because it's easier when all you do is mask off
the 60 x 60 top/bottom w/out resizing. the Interlace is completely
in tact and no distortion. I then encode this inside TMPG, by
selecting both Interlace options, and turning on 16:9 for a final
finish.

I also Anamoriphisize too.., close to 1.85 or 2.35 (but I'm still
experimenting on a final destination. I can still do this inside
TMPG rather cleverly. Lately, I was working on a 1.85 AR, and I
think I got it right, using my DVD movie "Deuce Bigalow" as a
reference, and dvd2avi v1.85 as the too to gauage with.

If you want to see a sample from my footaging, I'll try and crop
up something real quick for you to D/L. But, I tell you, there
is abosolutely NO distortion. Maybe some slight detail loss, if
you look for them. Otherwise, no quality loss. Remember, with
DV cams, there is no blocks to be found like there is when you
capture something from Satellite. So, DV is much like an original
source w/out blemish.

-vhelp

[dphirschler]

Let me clarify something. When I refer to anamorphic widescreen, I mean 16x9 (1.78:1) footage condensed horizontally to 720x480. When played back on a 16x9 TV, it fills the frame (no matter what the aspect ratio is). When played back on a 4x3 TV, it condenses it vertically and adds 60 black lines at the top and bottom*.

This is easy with progressive material, but interlaced material (ie video) does not scale without first de-interlacing it. So I wonder if the players deinterlace it, scale it, and then re-interlace it. Or is doing 16x9 anamorphic video illegal according to the DVD spec?


Darryl

* NTSC by the way. PAL adds more lines.

[Cornucopia]

I think you answered your own question, in that "some DVD players anamorphic/letterbox resize better than others". Some may do Bob/Weave before resize, some may just average ( ). AFAIK, it is not illiegal in the spec to create anamorphic interlaced material, just not optimal quality and not the most professional practice.

Scott

p.s. I'll check my DVD DeMystified book and other materials about the legality of this.

[FulciLives]

Hold on !!!

You can resize interlaced video without the need to deinterlace it.

It's not that hard really. Basically you separate the fields ... resize each field ... then weave them back together.

This can be done in AviSynth as well as VirtualDubMod.

So for an NTSC capture of 720x480 you cut 60 from the top and 60 from the bottom (this gives you 720x360) then you resize from 720x360 to 720x480 and you have a 16x9 anamorphic video.

For a PAL capture of 720x576 you cut 72 from the top and 72 from the bottom (this gives you 720x432) then you resize from 720x432 to 720x576 and you have a 16x9 anamorphic video.

Sure this is a trick in that you are converting a 4:3 WS image to a 16x9 WS image so you don't have the "extra" resolution you would expect from a true 16x9 WS video BUT I would think that it would be better to process it like this yourself (while encoding the capture to MPEG-2) than to leave it 4:3 WS and let the TV/DVD player do the conversion.

- John "FulciLives" Coleman

[dphirschler]

Actually the source I had that inspired this thought was HDTV resolution. I had a strong suspiscion that it was interlaced (1080i). I wasn't sure how to get the show off the PVR box in 16x9 anamorphic. I kept getting letterboxed output. Fine, I will deal with that.

But in the mean time I came up with a scheme where I would zoom in on the left half and output that, and then zoom in on the right half and output that. Then I could easily reassemble the image (from the two captures) into 16x9 anamorphic.

The question for me was if it is interlaced, can I still make it anamorphic? And if it was anamorphic and interlaced, how would the player scale it on a 4x3 TV?

I will be very interested to see what DVD Demystified has to say about it (if anything).


Darryl

[FulciLives]

I've taken video captures and did the crop/resize trick to turn it from 4:3 WS to 16x9 WS and left it interlaced. I only have a couple 4:3 televisions so they looked fine to me.

Someone I know with a progressive 16x9 WS TV tried out one of these DVD discs I made in this way and he said it looked just fine and this is someone with a keen eye for video and what to look for.

So I see no issue in making an interlaced 16x9 WS DVD.

However ... I have no idea what crazyness you are up too with split screen HDTV source etc.

- John "FulciLives" Coleman

P.S.
I do have to be carefull when you do the resize on an interlaced source but once you know how to do that (see my first post in this thread) then it ain't no big trick.

[dphirschler]

However ... I have no idea what crazyness you are up too with split screen HDTV source etc.

When I output the HDTV program (from the PVR) via S-video, it either letterboxes the widescreen video or it leaves it full screen but crops the sides off. It was my hope that you could move the "window" to the left and crop the right right only, and then capture again after moving the "window" to the right. Then these two videos could be easily re-assembled in AVIsynth using the layer/overlay command. But the PVR would not allow me to move the view window left or right. It simply left it in the middle and cropped the sides.

That (failed) project got me thinking about 16x9 interlaced video. I am sure many music concert DVDs are shot on video. There's also anamorphic lenses for video cameras. So 16x9 video is possible. But the DVD player definately has to handle it differently when scaling for a 4x3 TV.


Darryl

[Cornucopia]

A reading of DVD DeMystified, showed that you can have either interlaced or progressive anamorphic 16:9 video conent authored on a DVD.
It's mainly up to the player manufacturers to decide how to treat it:

1. Some drop every 4th line (not good for interlace)
2. Some do unweighted average (less interlace problems, but blurrier)
3. Some do weighted average (less blurry, small interlace problems)

My guess is that some nicer ones also do:
4. DeInterlace-->Resize-->ReInterlace (probably a little better than #3)

So it sounds like it's not "illegal" accd. to the spec. You just won't know what you'll end up with in the end--depends alot upon the player.

Hollywood guys get around this by doing it naturally in progressive and 16:9 (or more), so they don't lose anything in the encoding.

***
Have you tried fooling your PVR into thinking that you actually have a 16:9 TV? Then it should retain the anamorphic style which you could cap and down-convert to SD/DVD rez.

Wait a minute! Did you say that it may be a 1080i HD signal?
That's not anamorphic, it's just naturally 16:9 (all HD formats are), and square PAR. What model is the PVR? Maybe you can hack it to get files over to a reg. computer and do a software downconvert. That way you can make it interlaced or progressive, etc. And if you're coming from 1080i, I wouldn't worry too much about interlace artifacts, they're minimal compared to SD interlacing.

[dphirschler]

...So it sounds like it's not "illegal" accd. to the spec. You just won't know what you'll end up with in the end--depends alot upon the player.

Thanks for looking that up Cornucopia.

Have you tried fooling your PVR into thinking that you actually have a 16:9 TV? Then it should retain the anamorphic style which you could cap and down-convert to SD/DVD rez.

That was exactly what I did, and I still got letterboxed output from the PVR! I am confused by this as you can imagine. Perhaps it sent the proper image over the component video cables. I could only hook up via S-video.

Wait a minute! Did you say that it may be a 1080i HD signal?
That's not anamorphic, it's just naturally 16:9 (all HD formats are), and square PAR. What model is the PVR? Maybe you can hack it to get files over to a reg. computer and do a software downconvert. That way you can make it interlaced or progressive, etc. And if you're coming from 1080i, I wouldn't worry too much about interlace artifacts, they're minimal compared to SD interlacing.

Right, it's naturally 16x9, but I intend to encode an anamorphic DVD unless I can only get the letterboxed image out of the PVR. At this point I am going the "hacking" route. It's not really a hack, but just connecting a laptop via firewire to the PVR and recording the stream as I play the show. My first attempt failed because the laptop was not fast enough. The second laptop is a 2.6GHZ machine so hopefully it will get it no problem. The PVR is the new Motorolla 6412 I believe. It's the dual tuner model.


Darryl