On Tuesday, Feb 8, 2005, at 17:27 Europe/Stockholm, John Gay wrote:
Well, I finally figured out how to get POV-Ray to output non-3:4 ratio frames,
so I'm playing around with using Wide screen setting.
For extra resolution, I'm generating 16:9 frames at 2048 X 1152 for scaling
down. The default output setting is:
PNG image data, 2048 x 1152, 8-bit/color RGB, non-interlaced.
Which got me thinking about colour depth again.
POV-Ray says that png and ppm formats can handle upto 16 bit/color RGB. And
the Hollywood standard for movie editing is 32 bit/color RGB.
Where did you get that info?
The "standard" for a long time has been 10 bit log (Cineon/DPX), which is what they scan raw film in for special effects and post processing.
That will give you 10+ stops, which is better than well exposed negs.
32 bit per primary would be an enormous overkill.
But I don't see anything in the how-to or man pages/help pages regarding colour depth?
Can I use 16bit/color RGB png or ppm images?
No. There has been some talk of extending the Y4M format to >8 bits, but today it it 8 bit only.
If you are just compressing the final result, it shouldn't matter, since the output will always be 8 bit because of the DVD standard. More bits is only needed if you have a long and complicated workflow.
I'm also thinking about trying 4196 X 2304 frames to scale down to 1024 X 576.
That is actually not the best way. Render in the final resolution and let the renderer do the subsampling is always best. It can also be very much faster, since the renderer can optimize the subsampling.
Time not being a factor, I prefer max quality, would yuvscaler or y4mscaler be
best for this job? I'd like to keep the maximum image quality right upto the
mpeg encoding stage.
Don't poopoo the rendering time; you might be looking at days per frame at very high resolutions, esp with a raytracer.
I still need to work on my modelling, but there are plenty of POV-Ray models
on the Internet if you know where to look.
Any other comments/suggestions about rendering images for wide screen DVD
resolution would be good on this thread.
Remember to think about non 1:1 pixel aspect ratios, and plan for interlacing. Also remember some RGB colors are invalid Y'CbCr so preview your test renderings in Y'CbCr before the final render.
/Roine
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