Noise, sharpness and resolution...

[Graeme Nattress]

No because downsampling is a sampling process and hence needs filtering to avoid aliasing conditions. And downsampling is doubly hard because although you can think of it as 4 image planes, it still represents the bayer data so each pixel in each plane isn't really next to it's neighbour but separated by a pixel from the other planes.

You can think of a bayer pattern as 3:1 compression if you like, but I'd suggest you'd get a better image doing traditional 3:2 image compression on the fully demosaiced and downsampled data than by downsampling wile still raw.

So yes, considered, tested and rejected.

Graeme

 

[Jason Tan]

...and this is why I was so baffled by the 200% blow up that looked great. I have no math argument to explain what I saw. And that was "before" sharpening - for those who conveniently overlooked that in my previous post.

Hey Dylan,
I think it's because 720P is about all you need to give the impression of sharpness on a screen that size. I have a 8 ft wide screen at home with a little 720p projector and I can't even see the segmented pixels beyond 8ft feet away. So in a DI when your sitting back 15-20ft (or more) I think you can only see up to around 720p anyway. I'm pulling these numbers out of the air but you know what I mean.

 

[shashbugu]

And I can tell you as much as from my experience, Im not at all impressed of the uncompressed arri raw files, kind of came like a small suprise but the noise we see in low lights on the MX is not so much compression as we might think it's, since on the Arri raw uncompressed it's just as evil, or I would say worse, since the uncompressed look of this sensor noise is something I find looking very digital where as the 3:1 noise is looking more organic. Did not think that that would be my reaction but testing and viewing results is far different from theory.

Keying on underexposed arri raw uncompressed files is quite a challenge, due to this super high per pixel noise.

I must say that my first reaction to Arri Raw on the Alexa Plus when I first bought it was YIKES!!!! where is all this noise coming from? kind of scary I tell ya. I thought it was the Gemini 444 Raw recording that caused the noise. Nobody a Arri has been able to explain the the sensor noise situation in underexposed images. Red Raw science is more forgiving and 5k definitely offers higher resolution and sharper images down scaled to 2k. They both look excellent in all situation even though the Alexa has a slight edge in the filmic look department (whatever that means).

 

[Keith Walters]

Hahahahaha

I know of cinemas occationally screening from pal dvd's and never have had complaints...

...but let's not go there

720 x 576 progressive component video can look a hell of a lot better than most people want to give it credit for, particularly if your DVD player has HDMI out.
What comes out of most DVD players is PAL or NTSC interlaced video.
Video intended to be displayed on an interlaced scan TV has its horizontal and vertical bandwidth reduced by about 33% to avoid interlace flicker. That's one quality hit.
The next quality hit comes from the need to shoehorn the colour information into the same channel as the luminance.
Modern "advanced decoders" can do quite a good job of separating them again, but it's still a quality hit.
With a 35mm film or high quality video source, you can indeed get away with DVD sourced material in a cinema projector, but only if everything is tweaked to perfection.
Most times, it's not....

 

[Steven Caesare]

Ah, makes sense.

Thanks again for the discussion Graeme...

 

[Hugues Wisniewski]

Not to forget the FX guys

Not to forget the FX guys

Noise, sharpness, resolution ... and pulling a key on a 1080p ProRes 4:2:2 is also really not the same story as in full res