When to go with 720p instead of 1080p? Bitrate dependent?

[DMagic1]

Heres my question/problem.....

I have a 1080p source that I am trying to fit on a dvd9 that will be played on a bluray player.
The bitrate to fit will bring it down to 6463 where as it was about 8900.
Would I get a better picture if I went ahead and resized it to to 720p with that same bitrate over keeping it at 1080p with that bitrate?

Thanks

[Snowknight26]

Better (eep!) picture than the 1080p encode? Or compared to the source? Bad comparison. :\

[DMagic1]

I meant after I encode it to the small enough size not compared to the original 1080p source.
Which would have better quality.

[Atak_Snajpera]

Would I get a better picture if I went ahead and resized it to to 720p with that same bitrate over keeping it at 1080p with that bitrate?
I would go for 720p because 6MBps for 1080p is too small in my opinion. Check my post here : http://forum.doom9.org/showthread.php?p=1218450#post1218450
You will see that difference between 720p and 1080p is not that big. Lower resolution + higher bitrate = Less visible compression artifacts.

[DMagic1]

I would go for 720p because 6MBps for 1080p is too small in my opinion. Check my post here : http://forum.doom9.org/showthread.php?p=1218450#post1218450
You will see that difference between 720p and 1080p is not that big. Lower resolution + higher bitrate = Less visible compression artifacts.

Yeah that just what I was thinking. Thanks for the help.

[Sagekilla]

That works two ways though. At higher resolutions, compression artifacts are comparatively smaller to the frame itself. On a 640x480 frame, they're much bigger compared to artifacts present in a 1920x1080.

[Blue_MiSfit]

Yep.

Some 1080p content looks quite good at 3-6mbps, some really needs 12-20 to look awesome.

~MiSfit

[DMagic1]

Guess it comes down to understanding your source. Dark scenes most likely won't look good at such a low rate. Other factors can play a big part in the bitrate requirement also.

[Sagekilla]

For most sources, ~6 mbps on 720p will provide very good quality. A few might require over this for some scenes, but it should look good otherwise. 1080p is tricky though. If you don't plan on watching it from about 4-5 feet away from a large screen, you probably won't notice compression artifacts as much, especially given their relative size to the frames.

I'd still go with 720p @ 6 mbps though, it's faster to encode and you won't have to worry so much that it might come out crappy.

[G_M_C]

[...]If you don't plan on watching it from about 4-5 feet away from a large screen[...]

There is yet another point to make on that subject; In many cases the benifit of 1080p is small if you sit more than 5 feet away from your screen. Simply because your eyes cannot see the higher resolution.

There are graphs on this subject to be found all over the net, i'll give one here;

http://tweakers.net/ext/f/U5oqdaKwq4Dh0j3QdeCq3zuo/full.gif

[DMagic1]

I see