resolution for pal - opinions

[blinkimage]

Just a thread to see who renders what for PAL DVD, both standard and widescreen.

I find the whole issue of resolution, pixel aspect ratios, image aspect ratios and field rendering mighty confusing. Does anyone have any real experience here? I find snippets of info here there and everywhere, but they all seem to conflict in some way.

My understanding, for PAL at any rate, is:

PAL 4:3
pixel aspect ratio 59:54
frame size 720x576

PAL 16:9
pixel aspect ratio 118:81
frame size 720x576

I need 'buttery smooth' qualities here.

[marco]

PAL rendering

Hi,

We do a lot of rendering for PAL DVD applications.

PAL D-1 (720x576) is a squeezed version of PAL (768x576) hence the pixelaspectratio of 1.067
PAL D-1 (720x576 pa=1.067) is the standard in videocamera's etc.
When people are talking of PAL ,99% of the time they mean PAL D-1

PAL 16:9 was introduced to support the 16:9 widescreens televisions with the same input signal......
PAL 16:9 is in fact is a very bad trick in order to make a fake 16:9 signal out of the standard 4:3 PAL resolution.The only thing to do is squeeze the 16:9 to a 4:3 frame with the same pixelheight (576)
So in order to get 16:9 with 576 height you have to get a width of 1024 pixels,squeeze these 1024 pixels to "720" and you get a pixelaspect of 1024/720=1.4222
This means that with standard PAL (720x576)resolution a 16:9 screen will stretch the image to 1024x576 ,as you can imagine this will decrease image quality quite a bit.
HDTV signal is the best direct input for a 16:9 screen since this is a "real" 16:9 signal

Also when rendering for televisionscreens (and widescreens) use field-rendering.
This improves animation smoothness a lot (most noticeable with horizontaly moving objects or camera's)

We use the following PAL definitions and settings:

PAL 4:3: 720x576 pixelaspect=1.067 (=768/720)
PAL 16:9 720x576 pixelaspect=1.422 (=1024/720)


regards,
Marco

[blinkimage]

Thanks Marco - very useful. I shall give it a go with your settings.

Most DVD players and modern TVs apparently playback NTSC signals. I myself import DVDs from the states due to price/features/availability etc. Does this mean that I could equally well create NTSC animations if they are going onto DVD, or should we stick to PAL?

What do you consider to be the advantages?

Thanks again

[blinkimage]

...and another spanner in the works...

what about plasma screens. Should these be treated differently? A lot of our animation work will be used in marketing suites, and plasma screens are becoming increasingly popular presentation format.

What settings are recommended for these?

[marco]

blinkimage,

the NTSC format is not very common in europe,the main disadvantage of NTSC is that it carries less information (PAL 720x576, NTSC 720x480) on the other hand NTSC uses a playback framerate of 30 fps against 25 fps for PAL (higher fps means smoother motion)

If your artwork is going to be displayed in europe I would definitely use PAL.

About the plasma-screen:
At work,we have a large plasma screen for testing purposes (donated by our main customer Philips)
After some extensive testing we concluded that you should treat this plasma-screen just like a normal tv-screen when displaying DVD's

Note that plasma-screens I've seen are 16:9 format,so you should be rendering to PAL 16:9 720x576 pixelaspect 1.4222 or 1024x576 square pixels and squeeze down to 720x576 in after-editing.(note that 720x576 pa1.4222 renders aproxx. 40% faster then 1024x576 with the same endresult on PAL DVD.

Also use field rendering,I'm not sure if a plasma-screen uses (electronically controlled,no electron beam) interlacing to create an image but :
1) The screen is optimized to work with standard PAL input wich does use field interlacing.....
2) Some simple tests have shown us that an animation with field rendering displays much,much smoother than one without fields.

Make sure you render with the same field order as your after editing software uses,otherwise you get very ugly artifacts......

regards,
Marco

[blinkimage]

thanks again marco. What do you use for your post production software. Premiere/After Effects/Combustion?

[marco]

I,m a 3D-modeler/animator.
For post-processing we mainly use Finalcut-PRO on a dual G5 Mac,and occasionally After Effects/Combustion for 3D compositing.

Marco

[ZepSOFD]

Marco,

For my own benefit what would be the advantages/disadvantages of rendering a 16:9 frame at 720xwhatever w/pa1.0? wouldn't this render even faster then pa1.4222? and just be easier to deal with in post.

tom

[ZepSOFD]

Could anyone help with this question?

Thanks,
tom

[roppin]

what is your filtering settins for pal television display. I have tryed the video filter but I think it get´s to blury

Daniel

[theo]

what would be the advantages/disadvantages of rendering a 16:9 frame at 720xwhatever w/pa1.0? wouldn't this render even faster then pa1.4222?

changing pixel aspect won't change a second to your rendering speed
if resolution stays the same.

btw rendering at 720x576/pa 1.0 is 3:4 and not 16:9 you'll obviously get a stretched picture trying to fit your 16:9 format with it.
take the time to understand what mario wrote ..
it was pretty clear pal+ 16:9 is 720x576 pixelaspect 1.4222
or 1024x576 pixelaspect 1.0

[ZepSOFD]

Theo,

It seems to me that my mis-understanding is that the height of the frame is actually driving all the math, I was thinking the width was. So, that if I wanted to render 16:9 I would render frames at 720x506 pa1.0 which would render faster than 720x576 pa1.42. Then for me to do this correctly I need to know which frame height to use (NTSC, PAL) then which format (4:3, 16:9) then adjust pa as needed to make a circle round on the target display, does this sound like an appropriate general rule.

thanks,
tom

[marco]

Roppin,

Yes,the video filter is to blurry
I always use the default Area filter with VRay anti-alias settings on fixed-rate 3 (renderfarm will do the rendering,and definitely no AA-artifacts afterwards......)



Tom,

correct,but don't forget the framerate at which you render your animation (PAL 25 fps NTSC 30 fps)



Marco