704x400 versus 704x396: Does it make a difference?

[comatose]

Originally Posted by Dark Shikari

If a hardware player "didn't support non-mod16", it couldn't play 1080p , because 1920x1080 isn't mod16 either.

But are they encoded as 1080p?

I haven't gotten my hands on a bluray/hddvd iso yet, so I wouldn't know, but I've been thinking that they may have been resized to 1920x1088 and encoded, and then resized in the player to 1920x1080.


Anyway, is there a flag for the AVI container that lets you set the AR/resolution?
For the most part, I use 704x400 only with XviD encodes, which I make for the people who want to play the video on hardware players or have lesser computers... so, does AVI have a flag like this as well?

If I understood correctly, it doesn't, but I need to make sure.

[Dark Shikari]

Originally Posted by comatose

But are they encoded as 1080p?

I haven't gotten my hands on a bluray/hddvd iso yet, so I wouldn't know, but I've been thinking that they may have been resized to 1920x1088 and encoded, and then resized in the player to 1920x1080.

That's exactly what "encoding 1080p" means. If you don't encode mod16, the encoder pads it with a few lines of appropriate color pixels, and leaves a flag in the stream to crop it on playback.

Originally Posted by comatose

Anyway, is there a flag for the AVI container that lets you set the AR/resolution?
For the most part, I use 704x400 only with XviD encodes, which I make for the people who want to play the video on hardware players or have lesser computers... so, does AVI have a flag like this as well?

Yes, but basically nothing supports it.

[TheFluff]

It's also possible, even with ASP codecs like XviD, to set a PAR flag in the bitstream. That should work in most places, I would think (but I've never tested it extensively).

[technomo12]

it differs by a 6 pixel to the square power

thats all hmm maybe???

[guest0815]

Hi, I'm noob and have some noob questions. I hope it's not too much of a bother.

I got a recent japanese capture in 1280x720. No letterboxing or anything so the actual picture's 16:9. I want to try a resize to 704x400 to learn resizing, which brings me to the first question.

Where does that 704x396/400 resolution come from? Why not use 768x432 and be mod16 without distortion or cropping?

So, I understood it like that:

I push the height from 720 down to 396 keeping the width at height*width/height which gets me 704x396. Then I change the height to the next mod16 711.11x400 and crop the excess pixel of the width down to 704 again. I've got a few questions regarding that.

What about the fractional numbers? Will 0,5 be displayed as 0 and 0,6 as 1 and I have to base my cropping on the rounded values? So I'd have to crop 7 pix to get from 711 to 704?

And what would I enter into a resizing avisynth script that's only accepting integers? Would I round down a resolution of xxx,5 pixel myself and introduce a small distortion?

And my last question. I used VD's resize filter to scale 704x396 to 711.11x400. I only constrained it to 16:9 and didn't use any other options like codec friendly sizings or boxing/cropping. Hitting ok the filter output reads 711x400.
BUT if I load the same file into VD through a script using nothing but AVISource ("C:\file.avi") and repeat the exact same steps the filter output will read 710x400 O_O

Any ideas?
I wanted to take the advice and concentrate on scripts but avisynth potentially pushing my error range of 0,5pix (?) up to a max of 1,5 is disheartening T_T

Thanks for reading.

[Dark Shikari]

Originally Posted by guest0815

Hi, I'm noob and have some noob questions. I hope it's not too much of a bother.

I got a recent japanese capture in 1280x720. No letterboxing or anything so the actual picture's 16:9. I want to try resizing to 704x400 to learn resizing, which brings me to the first question.

Where does that 704x396/400 resolution come from? Why not use 768x432 and be mod16 without distortion or cropping?

Because in the past, most sources have been DVD or television or similar, and therefore a native resolution of 720x480 or similar magnitude, and upscaling is bad.

[TheFluff]

Originally Posted by guest0815

What about the fractional numbers? Will 0,5 be displayed as 0 and 0,6 as 1 and I have to base my cropping on the rounded values? So I'd have to crop 7 pix to get from 711 to 704?

you cannot crop to fractional pixels

[edogawaconan]

Originally Posted by guest0815

Any ideas?
I wanted to take the advice and concentrate on scripts but avisynth potentially pushing my error range of 0,5pix (?) up to a max of 1,5 is disheartening T_T

I'm amazed that you can tell the difference. I can't detect any AR errors at less than 10px.

[guest0815]

Haha, of course I can't. It just makes it seem even more redundant to correct for a mere 4 pixel (396-400) when it's not even accurate. Probably just be a problem with the vdgui though.

[jongu]

We need odd numbers like Mod17 or Mod19 (Prime number, even better).
People nowadays getting too fun with the upscaling that they won't be satisfied with multiples of 4 anymore.

[comatose]

That's exactly what "encoding 1080p" means. If you don't encode mod16, the encoder pads it with a few lines of appropriate color pixels, and leaves a flag in the stream to crop it on playback.

Well, this is a very late reply, but actually it isn't.

What I said is maybe it would be better to *resize* (not pad) to a mod16 res, and then on playback, resize again to the appropriate resolution (instead of cropping).

[Dark Shikari]

Originally Posted by comatose

Well, this is a very late reply, but actually it isn't.

What I said is maybe it would be better to *resize* (not pad) to a mod16 res, and then on playback, resize again to the appropriate resolution (instead of cropping).

Resizing unnecessarily for a few pixels is stupid, since resizing in any direction always introduces some form of aliasing and loses some detail.

[comatose]

I figured it would be more efficient since everybody always say you should use those extra pixels instead of leave it at a non-mod16 res...

Besides, resizing up so little and then back down to the original res shouldn't introduce any visible artifacts...

[Littm]

Hm, if we're talking here about resolution now, than I'll ask one interesting question - is there a real reason for fansubbers to making upscales (for example, from 740x480 to 1280x720) ?

[martino]

No, none.

<spacefill>

[Koroku]

Most fansubbers seem to think that if the raw is 1280x720, then of course the source must be as well.


Which of course, it isn't. :>

[edogawaconan]

Originally Posted by Koroku

Most fansubbers seem to think that if the raw is 1280x720, then of course the source must be as well.


Which of course, it isn't. :>

correction: it isn't always the case

[TheFluff]

the broadcasts are almost always 1440x1080, obviously we must release everything as 1080p

[DmonHiro]

Originally Posted by Littm

Hm, if we're talking here about resolution now, than I'll ask one interesting question - is there a real reason for fansubbers to making upscales (for example, from 740x480 to 1280x720) ?

Not really. Fansubbers don't ACTUALLY do the upscaling themselves (I belive), the raws are already upscaled. Itazuka Na Kiss, for example, had upscaled 1200x720 raws. Subbers could either use them like that, or downscale them to 700x400.

Now, I belive you are talking about upscaling DVDs, since you said 740x480. The answer is yes, sometimes there is a reason. For example, the upscales of Kodomo No Jikan (don't remember WHAT group) were actually better then the normal resolution ones. Weather that is because of the upscaling or the fact that all the other raws were not ecoded very well, I do not know. Other times, you end up with the exact same quality, only with a higher resolution, like some Baccano! raws that were around a couple of months ago. Most of the times, however, you end up with bloated pixels, and lost details. So it's really a matter of the original DVDs

[checkers]

you can't add quality by upscaling except in two ways:
1. softsubs overlaid on the video are cripser -- if you even think super crisp subs look objectively better (I don't)
2. you can warpsharp / smooth lines better -- same caveat as above.