Please advise, anamorphic encoding ...

[Plamen234]

Full resolution anamorphic, after croping only black fields H=426 (for example)
what should we do?

1. crop to H=416
"-" lost material
"+" 0% resizing aspect ratio error (for H, in this case)
"+" more bits for the rest material

2. Lanczos4Resize to 416
"+" no lost material
"-" resizing aspect ratio error (H-error(max)=2.5%)
"+" less H-lines, more bits for the rest material

or
3. Lanczos4Resize to 432
"+" no lost material
"-" less resizing aspect ratio error (H-error(max)=1.4%)
"-" more H-lines, less bits for the rest material

I'd bet on 1.
Thank you for your advice.

p.s.: considering DVD movies, full res anamorphic encode, what about values of W=702 (or 700) and H=430 (or 428)? Should we go for Lanczos4Resize to 704x432 with insignificant aspect ratio error?

[Teegedeck]

Probably the answer you're looking for is '1', but just to make sure:

You crop into the picture to a mod16 resolution because you should under no circumstances leave residual black lines on the borders. You loose some pixels on the borders? Who cares?

You don't, absolutely don't use any resizer because this utterly destroys the idea of leaving the original picture intact.

You don't get any notable aspect ratio error because you use Pixel Aspect Ratio and resizing on playback also works with odd resolutions; it will also resize to 1022x or whatever.

[celtic_druid]

Resizing does have one benifit though. It shifts the original MPEG2 macroblocks.

[Teegedeck]

I'd rather think the loss is bigger than the gain. Especially the loss in compressibility (but also to a minor extent in fidelity). Also, shouldn't cropping 8 pixels from each left and right, as one almost always has to do, have the same effect?

[Plamen234]

Anamorphic encodes VS resized ones (1 DVD9 movie on 1 dvd-r)

Just some thoughts.
I know the recommendations but is it worth (considering only the quality of the final video ready for playing)?

Anamorphic:
"+" keeping the original material
"+" no aspect ratio error (when only croping)
"-" more H-lines = less bits for a frame (or may be I'm wrong???)
"-" realtime resizing done by the player = more calculations load and "-" using the player's build-in resize filter (with MPClassic this filter can be user selected but again ending with a resized image)
"-" the H=16*Y W=16*Y requrement for stand-alone-players compatability = croping the frame

Rezised movie
"-" sometimes little aspect ratio errors, about 1-2% (resizing after croping) and can be even perfect 0%
"+" no H=16*Y W=16*Y requrement for compatability with hardware players (they just play the movie) = no lost material
"+" no realtime resizing done by the player (software or HW) = less calc load during play
"+" less H-lines = more bits for the rest

I'd be glad to see what you think?
Thank you in advance.

[Plamen234]

Thank you for your attention.

So I'll continue only croping to a W=16*X H=16*Y image as close as possible to the ful res.
Although the compression ratio fell to 49.5% for anamorphic 704*416 compared to 77% on 704*298

[Sharktooth]

Anamorphic has one big advantage over resizing: smaller artifacts (blocks and rings)...

[Teegedeck]

Plamen234, I've merged your two threads which are on slightly different aspects of the same subject. Please try to keep a discussion within one thread where possible.

To answer that other question: If it's only the main movie onto one DVD-R you should have more than enough space to stretch the movie before encoding. If you also want to put the extras onto the DVD-R perhaps not. Just my 2 Cents.

[Plamen234]

The movie (no extras, 1x ac3 stream) is about 7GB

[Teegedeck]

Do a compressibility test using Enc (http://forum.doom9.org/showthread.php?s=&threadid=50714) to decide. I'd say, try a filesize prediction with the SixOfNine CQM at constant quant=3 - if the upsized movie is predicted to come out too large at quant=3, I'd go for anamorphic.

[Plamen234]

enc gave these results after 10% analysis: 214% at the desired filesize, CQM HR@q3, anamorphic 16:9, b-frames 1/1.00/1, sensitivity=-3, ME4, VHQ3, Qpel
I'd try UHR@q2 (and 6of9)

uhr@q2 gave 49% compresibility
uhr@q3 - 98%

[Plamen234]

So, for this scenario: 1 movie on 1 dvd-r, anamorphic - we should aim to find the preset that gives video compression in % as close to <100% as possible. Right?

Thank you for your help.

p.s. I know the 3 golden rules
Originally Posted by Teegedeck
If you get undersizing use a higher preset
If you get oversizing use a lower preset
If you get oversizing at the lowest preset, decrease your resolution

[Teegedeck]

Welllll... What happens if you enter your aimed-at filesize and
[...]
Just start up Enc, select your .avs, choose 'compressibility check' and enter the filesize you're aiming for in kilobytes. Then you have to configure XviD. Set it to single-pass, constant quantizer=3. Load the SixOfNine (non-VHS!) CQM and set b-frames to max=2, ratio=1.62, offset=0, ME-precision to 4, VHQ=off, Trellis=on, Turbo=on and no other switches at all. (That means, it'll go damn fast...) Then run Enc. The outcome will be a percentage value. And here are pointers as to how to interpret the result:
<30%: bad luck, decrease resolution
>30%: you can use the 1-2 CD preset
>44%: you can use the 2-3 CD preset
>60%: you can use the 3CD - DVD-R preset
>90%: you can use the DVD-R preset?

P.S. It will be >90% and the DVD-R preset, I'm pretty positive about that.