640x480 or 720x480?

[Bear]

From your point of view, do you prefer 640x480 or 720x480 resolution? Assume the video quality are the same.

[Didée]

768*576

[unmei]

640x480 plays on this computer :)

i sometimes also encode 768x432 16:9 or 768x576 4:3 but then also use he-aac as i already know it will not play well on slowers comps and accept i can only watch it on the faster box.

I really don't know why 720 ..because a PAL DVD has 720 ? well actually is 704 plus 2x8 black border. I haven't seen yet one that uses the full 720 and i bet a player would cut it off and resize only 704 to the actual display resolution..

[mf]

896x672 :D

Anyways, 720x480 is just as crazy as 720x576. Both have screwed up aspect ratio. But they're nice to upsample to 768x576 from :rolleyes:.

[r6d2]

IMHO, a 720x480 source is best cropped 8 pix from sides and encoded like this:

704x480 if destination is MPEG-2 (you can play it on you PC or TV)
640x480 if destination is MPEG-4 (for PC DivX/XviD playback)

If you use this, and play on your PC on a 1:1 pixel aspect ratio resolution, like 640x480, 1024x768, etc, resizing at playback time will produce the less artifacts.

/Add:
For the theory behind this, as well as for the PAL case, this (http://www.uwasa.fi/~f76998/video/conversion/) page may be useful.

[mf]

Originally posted by r6d2
/Add:
For the theory behind this, as well as for the PAL case, this (http://www.uwasa.fi/~f76998/video/conversion/) page may be useful.
That page has totally ruined its credibility for me:
Shocking, isn't it? 768×576, 720×576, 704×576, 720×480, 704×480, 640×480... none of them is exactly 4:3 or 16:9; not even the ones you may conventionally think as "square-pixel" resolutions
Nice BS he's selling :). At square pixel aspect, 768x576 and 640x480 are certainly 4:3. So much for trying to clear up the confusion.

[Wilbert]

Nice BS he's selling :). At square pixel aspect, 768x576 and 640x480 are certainly 4:3. So much for trying to clear up the confusion.
Not necessarily ... It all depends on your active capture window (one of the threads in capturing forum). Of course, we are talking about analogue -> digital here.

If your capture window is 53.333 mus, and you are able to capture at 768x576 (I don't know any card what can do this). Then the image is not 4x3.
If your capture window is 52 mus, and you are able to capture at 768x576. Then the image is exactly 4x3.
If your capture window is smaller than 52 mus, and you are able to capture at 768x576. Then the image is not 4x3.

[r6d2]

Originally posted by mf
That page has totally ruined its credibility for me:

Nice BS he's selling :). At square pixel aspect, 768x576 and 640x480 are certainly 4:3.Well, seems you did not get to this part:
As for my calculations; feel free to prove them wrong.:)

The answer to your question may be further below, almost at the bottom of the page.:
4.8 Why does your table list two slightly different definitions for square pixels?
"Square pixels", as digitized by a TV tuner or an M-JPEG card, are not exactly square. The "industry standard" sampling rates used in square-pixel video equipment actually give out pixels that are almost square, but not exactly. As you can see for yourself in the table, the difference is very small - for all practical purposes insignificant - but it is still useful to know that sampled "video" square-pixels differ a bit from ideal "computer" square pixels.

Converting "computer" square pixels to "video" square pixels is a futile effort. You will not see the difference, anyway, and probably only lose some quality in the interpolation process

[mf]

Well ok, but formulating it that way isn't going to clear things up too well :).

[RadicalEd]

I've found that the most error-free way is to not deal with resizing in preprocess at all, but instead to use anamorphic encoding with the exact PAR. Otherwise you have to jump through loops to make sure the AR is perfect, or just accept a slight error.
crop(8,0,-8,-0).lanczosresize(640,480) is an approximation.
The uwasa page is actually extremely useful for really understanding AR.

[r6d2]

Originally posted by RadicalEd
crop(8,0,-8,-0).lanczosresize(640,480) is an approximation.This should be as close to perfection as you can get:crop(9,0,-9,-0).lanczosresize(640,480)0.03% aspect error.

[RadicalEd]

YV12 can't be cropped to < mod4 resolutions, so if you're going to convert colorspaces, may as well go RGB and crop to 711x480, resize to 648x480, and crop to 640x480. That will give exactly 0% AR error. Assuming the source is actually perfect ;)

As long as you're staying mod4, 704x480 is the best estimate at about 0.25% error. Though, I just calculated, and resizing directly to 656x480 and cropping to 640x480 will give an error of only 0.03%.

I maintain my stance that flags are nicer :P

[Selur]

yup, anamorph encoding should be the way to go :)

[ChristianHJW]

Resizing Filter = EVUL !!

Just crop to mod8 and use a better container, allowing AR correction on playback ....

[scharfis_brain]

instead of using crop(9,0,-9,0) use crop(10,0,-8,0) and you'll receive no probs with YV12. the slight horizontal offset is hardly noticable!

EDIT: neither using 720x480 nor using 640x480. I am a PAL-User.

[mf]

Ignorance is bliss. I accept small AR errors, like cropping off black borders on a 640x480 source and re-expanding it to 640x480. Am I Evil? Yes I Am!

[LordDethstar]

Originally posted by mf
Ignorance is bliss. I accept small AR errors, like cropping off black borders on a 640x480 source and re-expanding it to 640x480. Am I Evil? Yes I Am!

Finally, another normal person. I usually encode my movies at 640x480 for 4:3 and 720x304 for 2.35:1, after cropping away any black or fuzzy borders. Nobody would ever notice such a small aspect ratio error.

[Soulhunter]

Originally posted by mf
...Am I Evil? Yes I Am! [/i] Thought all evil guys would wear a moustache... :D :D :D

[r6d2]

Originally posted by LordDethstar
Finally, another normal person.Well, for the rest of us subnormals Jukka Aho has an answer too: :D
4.10 I think you're just nit-picking. No-one will ever notice if I consider all "4:3" video formats just 4:3, without doing any complicated aspect ratio or "active image area" calculations.
Feel free to process your video just the way you like it. But there are still many people who would like to get as close to the ideal aspect ratio correctness as possible, instead of only using rough "ballpark figures" in their video work.

[mf]

Nitpicking isn't a bad thing! I'm a master nitpicking in pixels. I'm just not good with numbers and lazy to boot so that's why I prefer not to care about aspect ratio too much.

[RadicalEd]

Originally posted by scharfis_brain
instead of using crop(9,0,-9,0) use crop(10,0,-8,0) and you'll receive no probs with YV12.

When I tried that last night, it said that the non-mod4 resolution (702x480) couldn't be processed in yv12 or yuy2 :|