Minion's image guide for retards

[Pwolf]

you make a point on how it didn't go deep enough. i was depending a bit on the editor's common since.

99% of beginners don't have common sense

Pwolf

[DJ_Izumi]

Okay... *sigh* I'll explain this DPI thing to you since you don't understand it outside of print.

'DPI' means how many dots (or pixels) per inch are represented. Which means the ammount of pixels in the image is a result of two sets of numbers. The DPI value and the physical dimensions value, which is in either inches or centimeters. When we're dealing with digital media however, the physical dimensions in inches or CM don't really exist. It's a made up value using the DPI value and the actual count of pixels. But it has no true physical dimensions because it is not a real object, it's virtual.

A 720x480 image with a DPI of 72 has dimensions of 10" x 6.667"
A 720x480 image with a DPI of 300 has dimensions 2.4" x 1.6"

However, opposite of you claims, if both images are of the same resolution, that is 720x480, they will look EXACTLY the same. Because they are exactly the same. Every pixel is identical in the two images. (Obviously, assuming they are from the same source) In a computer what TRUELY represents an images resolution is the dimensions in terms of pixels, not inches and not dots per inch.

As I said before, if you arn't scanning or doing work for print, DPI has no true meaning here and is entirely irrelevent.

However, I must admit, that this explination assumes you do know what a 'pixel' is and I sadly am not enturely sure you understand this basic element of graphics.

[dokidoki]

So, since my video will be played on a 50-foot screen at Otakon, my 300dpi graphics should be around hmm, carry the three... 270,000x180,000?

Aagh! Out of memory!

(screen may not be 50 feet)

[trythil]

i may accept missleading, as some people may have taken the examples provided as suggestions, but i don't see anything wrong. this is a guide for beginners, and people could get by just fine with my information.
true, a majority of my work is pre-press, but unlike web/print, video/print are similar in the demand for image quality (which i provided good information for)

You said that people should create images at 720x480:


Let's resize this for NTSC 4:3 material:


...and let's resize this for NTSC 16:9 material:


Conclusion:

What you suggest isn't "getting by just fine". It's "totally screwing up", and it isn't acceptable to teach anyone the method you propose, especially when there exists simple mathematics to create images at dimensions that will properly distort when resized.

Simple enough to be taught to a beginner.




There's still some error because the numbers I chose aren't exact, but the error introduced is substantially smaller than the methods you proposed, which I think makes my method far superior.

Or does it? I'd like to see your rebuttal to my statement.

[Minion]

so then make your circle after you resize

[trythil]

so then make your circle after you resize :roll:

That's useless and impossible if the imagery you are creating contains circular elements or anything else that requires maintainance of aspect ratio.

[trythil]

so then make your circle after you resize :roll:

That's useless and impossible if the imagery you are creating contains circular elements or anything else that requires maintainance of aspect ratio.

Additionally, resizing video is not always done as a prerequisite to editing, and indeed does not have to be done that way. Which is why pre-deformation is sometimes useful.

If you resize video before editing, then you can create images at the resized resolution and plop them in. That's also fine.

What's not fine is creating imagery at 720x480, because of the distortion problems I mentioned above.

720x480 is also not a standard resolution on any video system, despite what DVDs do. See http://lipas.uwasa.fi/~f76998/video/conversion/ .

[trythil]

720x480 is also not a standard resolution on any video system, despite what DVDs do. See http://lipas.uwasa.fi/~f76998/video/conversion/ .

That's a little misleading, actually.

720x480 is a DVD standard, but it won't get you a proper 4:3 or 16:9 image frame with any television standard. Actually, none of the "common" formats will, but there are some that are much closer than others.

720x480 is way the hell out there.

[Willen]

The only real reason that DVDs are 720x480, aside from the fact that TV's use rectangular pixels, is that it is a compromise resolution. It does fall between the 640x480 square pixel resolution for 4:3 and the 848x480 square pixel resolution for 16:9. So 4:3 needs a little "squeezing" to look right and 16:9 needs a little "stretching" to look right. But both can be stored on DVDs the exact same way, properly flagged of course, so the player will adjust to the correct display aspect ratio (DAR).

I know EADFAG's section on PAR and DAR, widescreen and 4:3 isn't the best, but it does explain what you need to do to get correct geometry for imported graphics and your final output. Maybe it needs to have the red text

NTSC footage technically has a PAR of 0.911 and PAL has a PAR of 1.094 but we are going to work from the following principle - on a PC monitor, NTSC dvds need resizing to 640x480 to be 4:3 and PAL DVDs need resizing to 768x576. This is a simplified version of the truth but it suits us well enough.

[You may notice that NTSC is downsized and PAL is upsized - this is purely and simply to keep the vertical resolution the same in case someone uses these values on an interlaced source]

blinking and at 50 point size or greater.

[DJ_Izumi]

At least HDTV eliminates the PAR issue. It's not complicated but every noob often needs it explained to them.