letterboxed source, encoded to anamophic... better or worse??

[E-Male]

when i have a letterboxed source, let´s say a capture
i see 2 ways how to encode it to mpeg2 for use on DVDRs

1) crop of the black bars (crop), add them back (addborders) and encode and author it as 4:3 [letterboxed]

2) crop of the black bars (crop), get the right AR [1.7something] (addborders, maybe crop), resize to full resolution (lanczosresize) and encode and author it as 16:9 [anamorphic]

now i´d like your opinions: Which of these should be better?? [at the same bitrate]

CU
E-Male

[FamousPerson]

E-Male:

Unless I'm misunderstanding you, I don't see what the purpose of #1 is at all. You remove the bars, then re-add them, then encode? Why bother removing & re-adding them?

As far as your question "which is better" is concerned, I'd like to know what you mean by "better". If you mean better picture, then I would say it does not matter unless you plan to watch it on a 16x9 TV. If you plan to watch it on a 16x9 TV, then I would re-encode to anamorphic because lanczosresize probably does a better job of resizing to a larger picture than your TV does on the fly. Just a guess though.

Incidentally, the avs script for converting 4x3 LTRBX to anamorphic is:

YourFavoriteResize(720,480,1/3,1/3,0,60,720,360)

for NTSC and

YourFavoriteResize(720,576,1/3,1/3,0,72,720,432)

for PAL

[E-Male]

Originally posted by FamousPerson
E-Male:

Unless I'm misunderstanding you, I don't see what the purpose of #1 is at all. You remove the bars, then re-add them, then encode? Why bother removing & re-adding them?

i just want to change the "something close to black" i capped to "perfect black"

[FamousPerson]

I see. That makes sense.

Well, like I said, if you have a 16x9 TV or plan to get one someday, anamorphic is the way to go.

[E-Male]

and anamorphic also has no downside?
if it´s so, then i´ll use it, "sometimes better, never worse" seems fine to me

[FamousPerson]

Downside? Well, not if the source is originally anamorphic. If you resize your source (larger) to make it anamorphic it won't be as good as if it started out anamorphic, but if watched on a 4x3 TV your DVD player will shrink it back down and add its own black bars anyway, so yes: sometimes better, never worse.

[xmenxmen]

Option 2, I would think.

The last movie that I did like this, I just crop the border to 16:9 and resize using avisync and set it to 16:9 on the dvd and enable letterbox. This way, you will have more space for quality as well as it will look better on a wide screen tv. Watch on a 4:3, the letterbox option will put the black line back.

Why normal 16:9 for me, it was easier to figure out then trying anamorphic.

Either way, no reason to do option 1, as letterbox will give you real black (if you call it that way)

[E-Male]

seems my idea of turnign material into anamorphic is not as dumb as some people want to make me believe

[FamousPerson]

Dumb? Who told you that? I turn everything into anamorphic if it's not already.

I have a 16x9 screen an I like to watch with subtitles on. If you watch a letterboxed 4x3 movie on a 16x9 TV, the subs are cut off.

[jdobbs]

I can see someone telling you not to resize if it will fit without reencoding. But, if you are reencoding anyway (which is almost always the case) -- remove the bars and resize to 16:9 anamorphic. Let your player do the letterboxing until you get a 16:9 TV. You should also use bicubic resize, it does a better job when resizing to a larger picture.

[E-Male]

ok, what exact parameters would you recommend for the bicubicresize?

[jdobbs]

Here's what I use in AVISYNTH

LoadPlugin("C:\PROGRAM FILES\DVD-RIP\AVISYNTH\MPEG2DEC.DLL")
mpeg2source("d:\image2\infile.d2v")
BicubicResize(720,480,1/3,1/3,0,60,720,360)
ResampleAudio(44100)

[E-Male]

THX, i´ll do some experiments with the quality

[FamousPerson]

Pretty much what I said above, no?

[E-Male]

Originally posted by FamousPerson
YourFavoriteResize(720,480,1/3,1/3,0,60,720,360)

for NTSC and

YourFavoriteResize(720,576,1/3,1/3,0,72,720,432)

for PAL

so the resulting resolution (after the player corrected the AR) would be 720,360 for NTSC and 720,432 for PAL,
i thought it would be the same?

[FamousPerson]

No, it would be 720x480 for NTSC and 720x576 for PAL.

[jdobbs]

@FamousPerson,

Sorry - I didn't mean to repeat what you'd said, I guess I need to get some glasses...

[FamousPerson]

that's OK, I prolly got it from you originally anyway :)

[E-Male]

>>so the resulting resolution (after the player corrected the AR) would be 720,360 for NTSC and 720,432 for PAL,
i thought it would be the same?
-----
>No, it would be 720x480 for NTSC and 720x576 for PAL.
---
that would be full resolution
i mean the one before i strech it to full screen [which should be equal to the one that the player/TV will spit out at the end]

[FamousPerson]

well, they all start out the same:

In the case of NTSC, 720x480

Then, if the picture is flagged anamorphic, your DVD player will stretch it out to 853x480. If you have a regular 4x3 TV it will then add black bars.

If it is not flagged anamorphic, the DVD player will scrunch it to 640x480.

[ronnylov]

At the same bitrate the letterboxed video will have a better quality because less pixels to encode but the same bitrate will get less encoding artifacts. So specially if it's a very long movie the quality difference may be worth the smaller picture size when encoding letterboxed.

[E-Male]

Originally posted by FamousPerson
YourFavoriteResize(720,480,1/3,1/3,0,60,720,360)
for NTSC

but 720:360 would be 2:1, i never heard about that
only about ~1.7:1 and 2.2:1

[jdobbs]

You are not resizing to 720x360. You are resizing FROM 720x360 (the 4:3 letterbox) TO 720x480.

Syntax:

BicubicResize(clip, int target_width, int target_height, float "b", float "c", float "src_left", float "src_top", float "src_width", float "src_height")

Now -- if you are making the point that 720x360 is not correct for the original -- you are forgetting to consider that it is not within a 1:1 domain but a 4:3 domain... so you can't just divide width by height (720:360)...

16:9 = 1.7777777777:1
4:3 = 1.3333333333:1

So to convert from 4:3 to 16:9 you'd use (1.333333/1.7777777) which comes out to .75 --> .75 times 480 = 360

[jdobbs]

At the same bitrate the letterboxed video will have a better quality because less pixels to encode but the same bitrate will get less encoding artifacts. So specially if it's a very long movie the quality difference may be worth the smaller picture size when encoding letterboxed.

My experience leads me believe that to be incorrect. When you resize to a larger picture your are only "pretending" to increase the resolution through interpolation. The nature of the MPEG-2 encoder makes the interpolation have little effect and you will get close to equal compression at a given bitrate.

The only good really good reason not to convert is when you can avoid reencoding -- as there is no such thing as an "equal" second generation encode.

[FamousPerson]

To add yet another kink to all this:

I have actually been using this lately instead:

BicubicResize(682,480,1/3,1/3,0,50,720,380).AddBorders(19,0,19,0)

It will turn 4x3 LBX into anamorphic widescreen, AND it will shrink the picture a little bit while adding small borders to the left & right sides.

The idea is that most TVs "hide" that part of the picture anyway. This way you get to see ALL of the Film. In fact, on my TV, I still can't see the bars on the left and right - just parts of the movie I would have missed.

[bretbowman]

I'm very new to avisynth and the actual script editing process. I have a 4:3 LB movie that I'd like to practice with by trimming the black borders off and encode as anamorphic. What script file to I edit? or If I create a new script file, do I put it in directory with mpeg2dec.dll and how do I tell frameserver to use THAT NEW SCRIPT?

Forgive the newbie questions...but any suggests/help would be greatly appreciated.

[dirk67]

Hi,

a conversion from LB to anamorphic is only suitable for progressive material. I think E-male deals with TV captures, so his material will be interlaced. If you resize interlaced material in the vertical direction, you'll destroy your interlace pattern. Resizing interlaced material is only suitable in the horizontal direction.

Greetings,
Dirk

[Biggles]

Hi i have been using your avsynth script successfully with cce and tmpgenc to convert 4:3 letterbox to anamorphic. But have now hit a snag - i hae been trting to convert a 4:3 ntsc anamorphic video usign the avsyth code but end up with a green line on the right of the screen and cannot get rid of it - any suggestions?

[FamousPerson]

Please post your script.

[Biggles]

Sorry for not including script;

the script i have used is:
Import("D:\MOVIEF~1\RESAMP~1.AVS")
LoadPlugin("C:\PROGRA~1\DVD2SVCD\DVD2SVCD\AVISYN~1\Mpeg2dec\mpeg2dec.dll")
LoadPlugin("C:\PROGRA~1\DVD2SVCD\DVD2SVCD\AVISYN~1\AVISYN~2.DLL")
mpeg2source("D:\MOVIEF~1\DVD2AV~1.D2V")
BicubicResize(682,480,1/3,1/3,0,50,720,380).AddBorders(19,0,19,0)
AvisynthSubtitler("D:\MOVIEF~1\Subs\","permsubs.txt")
ResampleAudio(44100)

When I play the original movie in dvd2avi it seems to be in 4:3 aspect but the title above on the preview says vobxx 704 x 480 and looks letter-box so maybe this means it is not standard size hence the green line on the right when I resize.

Would this mean a
BicubicResize (704,480,1/3,1/3,0,50,704,360.AddBorders(8,0,8,0) would make sense or using the same framework as you have in your 682,480.... series and adding black bars

Not sure about this advice would be welcome.

[Biggles]

I am still having the same problem.

Further information. When the 4:3 aspect source is clipped the actual Picture size is 704x273, the rest of the aspect been black bars.

I woudl be grateful if you could comment on my script and suggest changes as it does not work - a right green bar remains.

Regards

[Biggles]

I am still having the same problem.

Further information. When the 4:3 aspect source is clipped the actual Picture size is 704x273, the rest of the aspect been black bars.

I woudl be grateful if you could comment on my script and suggest changes as it does not work - a right green bar remains.

Regards