lower resolution and artifacts

[jkwarras]

HI,

After reading a lot of discussions on this forums and do some tests, i really don't have clear why should be better a lower resolution that a higher resolution; Let's me explain: if you have a 4:3 TV capture, and you go to a bitrate target like 650-700 kbps doing a compressibility test will "suggest" you to go to something like 320x; You trust it, but the bitrate is low so if you watch it in the real size (in a small window) you see it clear and nice, but you watch it in full screen there's another thing! The artifacts (block and ringing) are very visible; and the edges of things are not very defined, very blurry.

Ok, DivX or XviD can't do miracles at low bitrates, but in fact, i tried with the same TV capture at the "desuggested" 520x and there the quality still the same, but the artifacts are a little less visible, and the edges weren't so pixelated;

So I know it's a mmater of taste, but it's really a lower resolution giving best picture quality, when you are going to watch it at full screen? It's really avoid compression artifacts?

Ivan

[manono]

Hi-

but it's really a lower resolution giving best picture quality?

It's a bit of a tradeoff between compress test percentages and resolution. As you discovered, sometimes to get a good percentage, you have to lower the resolution too much, and then there are other problems. Personally, for wide screen material I won't go below 576*xxx, and for full screen I won't go below 512x384. But different people have different lower limits. But at the very low resolution, such as your 320*xxx, the problems you describe make it unwatchable to me.

So what can you do? You can put the resolution back up and go for 2 CDs, use lower quality audio, and/or start using filters carefully. For example, if the source is noisy (and yours probably is since you said it was a TV capture), a decent Temporal Smoother can raise the percentage by 10% or so. And a combination Temporal/Spatial Smoother such as Convolution3D or FluxSmooth can also work wonders without much image degradation. But if you just use the higher resolution with a low percentage of 30-40%, then that's going to look pretty bad, I think.

[jkwarras]

but it's really a lower resolution giving best picture quality?

Personally, for wide screen material I won't go below 576*xxx, and for full screen I won't go below 512x384.

Thats also the limits i have, 512*xxx for almost 4:3 or 16:9, but i'm thinking of go a little high for 16:9 films; At the beginning i really thign it makes sens, i mean, the compressibility test, and going for a low resolution, but the fact it's that i don't really know if it's avoiding any artifacts or just making the encode looks great into a small window, but what's the reason if you are always going to watch it full screen?

For example, if the source is noisy (and yours probably is since you said it was a TV capture), a decent Temporal Smoother can raise the percentage by 10% or so. And a combination Temporal/Spatial Smoother such as Convolution3D or FluxSmooth can also work wonders without much image degradation.

That's what i do, and most of the noise is gone, but the bad side it's that it blur very much, but there's nothing to do about it if you go for 1 CD, i know; THe question i'm making myself is there's is realy any gains of lowering resolution for ex. for a 16:9 clean DVD film instead of going for 640*xxx, the image will be sharper and don't really know if you're getting more compression artifacts. Not really a simple question i know :)

Ivan