resizing, I'm confused!!!

[nalooti]

Hi,

I used to encode in Divx my family videos out of my digicam Canon Powershot S80 which gives Mjpeg format at 1024x768 resolution. When encoding, I resize (with the codec not with VirtualDub) at 640x480 resolution with square pixels. Please note that these two resolutions have 4/3 i.e. 1.33 aspect.
Since my Standalone player (Philips DVP5500) supports up to 720x576 resolution, i wanted to try other resolutions bigger than 640x480. And here come the results and my confusion:
1-custom size: 720x576 (1.25): Deformed
2-Square pixels at 720 width: produces 720x544 (1.32): almost OK
3-PAL at 720 width: produces 720x496 (1.45): Deformed
4-PAL at 640 width: produces 640x448 (1.43): Deformed

I understand that any aspect different than 1.33 would produce deformed videos; the only acceptable one is number 2 above.

But i don't understand why for example number 2 produces 720x544 (square pix) and number 3 produces 720x496.

What is square pixels and why it appears this is what i should use ?

Which resolution should I use? Should I stick with 640x480 at the first place or go for number 2 above?

I got another LCD HDTV connected to my PC. I wanted to try square pixels at 1024 width but VirtualDub gives me an error message (code -2) saying the "source image format not acceptable". What's the problem ? Vdub or the codec ? and how could i resolve the problem ?
Please note that PAL at 1024 width works good (gives 1024x704) and also custom 1024x720 works but i'm unable to do it at the original 1024x768 because the codec doesn't accept it. Why ?

Thanks for your help
nalooti

[MarcioAB]

Use your option 1 (square pixels for input and output) with a custom resize of 720x540.

Your source is 1024x768 resolution with aspect ratio (AR) of 4:3.
With these numbers your source has the pixel aspect ratio (PAR) of 1:1 (square).

A different example could be if your source had the same 1024x768 resolution but with AR of 16:9.
With these numbers your source had a PAR of 4:3 (non-square).

So, with a PAR of 1:1 and AR of 4:3 as your source is and limiting horizontal resolution to 720 the resulted vertical resolution is 540

(1024:768) = (720:540) = (4:3) * (1:1) = (AR) * (PAR)

[vlada]

nalooti
I would suggest you to use resize in VirtualDub. It will have better quality and much more options. Any resolution which results in 4:3 AR is fine: 720x540, 704x528 etc.

I don't understand your confusion...

[prof_unto]

If you have LCD, Plasma TV etc with progessive output then use Square pixels for the best result.

For 1024x768 try High Def mode

[DJ Bobo]

@ nalooti
I would stick to 704x528 square if I were you, because:
1) This is the highest perfect 4:3 resolution after 640x480
2) 528 is perfectly divisible by 16, which will guarantee optimal compression (if you choose 720x540, 540 is not divisible by 16, and if you adjust to 720x544, you won't have perfect 4:3 anymore)

[Sagekilla]

Accidental double post. Disregard this.

[Sagekilla]

You can try using anamorphic, with 720x576.. Simply set it to stretch back to 768x576 in the container you're using. I know mp4 and mkv supports this, but I don't know if divx does. But, avi won't work with anamorphic stretch at all.

This way, you can encode to the highest possible resolution allowed by your player (which is 720x576) and have it stretch to 768x576 for proper aspect ratio. This is how PAL and NTSC DVDs work for that matter, since they're encoded @ 720x576 or 720x480 respectively, and get stretched depending on what AR they are.

[DJ Bobo]

@ Sagekilla
He said, his player won't play AVIs w/ embedded AR right. MKVs and MP4s are no options, he needs standalone compatibility.