Shayne Lebrun
Screenwriter
- Joined
- Jun 17, 1999
- Messages
- 1,086
So I'm one of the blessed who has the DVD early. Watching it on me non-anamorphic DVD I notice tons and tons of aliasing artifacts. Real notable; when Anakin's taking out his podracer, watch the lines that it's being dragged by. One example of many.
But that got me thinking. The aliasing was only on the CGI stuff, reminded me alot of Starship Troopers. Same effect; the ships have a lot of stair-stepping when they move diagnoally across the screen. But the NON cgi stuff, was fine. For example, the Naboo Royal ship thingy is flying over a forest; the forest is fine, but the ship is aliased.
Now, my setup is a HTPC; I've a DXR3 card. So I switch the display over to my monitor, which the player goes into anamorphic mode for, popped it fullscreen, and sure enough, no aliasing. Looks great.
Now it's a fact that MPEG-2 encoding doesn't deal well with geometrically straight lines; and such things don't exist in nature. I can therefore conclude that the aliasing you see is because the CGI is too detailed; there is a black line on the ship, and that's that. There's no fading, no blending; the ship has an edge, and that's that. So when it's compressed, you get a stair step. This makes sense, when you think that one of the anti-aliasing tricks that's popular is to render a scene several times, then put them all together, so instead of getting
0
0
0
0
0
you might get
0
o0
o0o
o0oo
oo0oo
oo0ooo
which, when viewed at pixel size, gives you the gradiation between object and not-object that nature tends to produce.
Also, you get the problem that the CGI was probably done at film speed, which means you don't get the motion blur inherent to film; again, it doesn't look right, and doesn't leave a lot of 'analog' to cover up such things.
I'm going to try the same scene on me laptop tomorrow; I've got WinDVD and the Intervideo decoder built in. Both software. I can post screen caps if y'all would like.
But the long and short is, the aliasing appears to be a downconversion artifact that is made worse by the high level of 'difficult to encode, then difficult to downconvert' elements in this film.
But that got me thinking. The aliasing was only on the CGI stuff, reminded me alot of Starship Troopers. Same effect; the ships have a lot of stair-stepping when they move diagnoally across the screen. But the NON cgi stuff, was fine. For example, the Naboo Royal ship thingy is flying over a forest; the forest is fine, but the ship is aliased.
Now, my setup is a HTPC; I've a DXR3 card. So I switch the display over to my monitor, which the player goes into anamorphic mode for, popped it fullscreen, and sure enough, no aliasing. Looks great.
Now it's a fact that MPEG-2 encoding doesn't deal well with geometrically straight lines; and such things don't exist in nature. I can therefore conclude that the aliasing you see is because the CGI is too detailed; there is a black line on the ship, and that's that. There's no fading, no blending; the ship has an edge, and that's that. So when it's compressed, you get a stair step. This makes sense, when you think that one of the anti-aliasing tricks that's popular is to render a scene several times, then put them all together, so instead of getting
0
0
0
0
0
you might get
0
o0
o0o
o0oo
oo0oo
oo0ooo
which, when viewed at pixel size, gives you the gradiation between object and not-object that nature tends to produce.
Also, you get the problem that the CGI was probably done at film speed, which means you don't get the motion blur inherent to film; again, it doesn't look right, and doesn't leave a lot of 'analog' to cover up such things.
I'm going to try the same scene on me laptop tomorrow; I've got WinDVD and the Intervideo decoder built in. Both software. I can post screen caps if y'all would like.
But the long and short is, the aliasing appears to be a downconversion artifact that is made worse by the high level of 'difficult to encode, then difficult to downconvert' elements in this film.