Encode at 624x352 vs 640x360

vbimport

#1

When I’m converting various files to DivX format I’ve been using 640 x 360 resolution but I’ve noticed that most files I download are encoded at 624 x 352. I’ve read somewhere that it’s because that resolution is completely divisible by 16x16 blocks while 640x360 will only go to 8x8.

My question is “so what?”

Why is it important to have resolution divisible by 16 x 16? What do I risk using resolutions that only go 8 x 8 such as 640 x 360? Do I risk the file being unplayable somewhere?


#2

Might as well opt for blocks of 16x16.

[I]Video compression uses blocks of 16x16. If the resolution isn’t mod16, it will be padded (internally) to the next mod16 resolution and cropped back at playback time.
Hence you pay bits for parts of the image you’ll never see. So in CRF mode you have to expect a bigger file, in 2-Pass mode you have to expect worse quality at a given bitrate.[/I]

For my Xvid conversions if the source is 720 wide I keep it there.


#3

620x360 has a ratio that’s not correct.

620x360 is 1.72
624x352 is 1.77


#4

[QUOTE=Jedi Master Yoda;2188047]620x360 has a ratio that’s not correct.

620x360 is 1.72
624x352 is 1.77[/QUOTE]
[B]640[/B]x360 is 1.77, is what the OP mentioned.

Re: Encode at 624x352 vs 640x360


#5

My bad, don’t know where I got the 620 from, lol.


#6

My DVD player will play DivX AVI but only at 640 wide or less. It won’t do 720 wide. Anyway I’ll go ahead and start using 624x352 from now on and save a little space. I doubt I’ll see any difference in quality between that and 640x360.

Thanks to all who replied.