[Xperia Z General] Shasarak:
Everyone seems to be under the impression that Bravia improves the performance of the display. It doesn't. It has absolutely no effect on that at all - it can't have.

What Bravia does is simply to change the pixel values that are sent to the screen.

The display is 24-bit, so each pixel is has a red brightness, blue brightness and green brightness that varies between 0 and 255. Pure white would be red 255, green 255, blue 255; pure black would be red 0, green 0, blue 0. Suppose you're viewing a photo and there's a pixel in it that is dark grey - perhaps red 16, green 16, blue 16; and suppose there's another pixel in it that is a slightly greyish white - perhaps red 240, green 240, blue 240. What Bravia does is simply to change the dark grey pixel to a black one, and the greyish white pixel to a pure white one. So, instead of telling the screen "display r16g16b16", it tells it to display "r0g0b0"; and instead of telling it to display r240g240b240 it tells it to display r255g255b255.

The effect of this is that the photo appears to have better contrast; but you need to think about what happens if the photo already contains a pure black or pure white pixel. If the pixel is already r0g0b0 then Bravia can't make it any darker - it's already as dark as it can be. Bravia doesn't magically make the screen display black pixels as being darker than it normally would, it simply gets the screen to display dark grey pixels as "black". So, not only is it impossible for Bravia to affect the performance of the screen, it also has side effects. Imagine that you have a pure black pixel (r0g0b0) in the middle of an area of dark shadow that is r16g16b16. Without Bravia you should be able to see that there is an extra-dark spot in the middle of the dark shadow; but with Bravia on, the rest of the shadow gets bumped down to pure black. The dark pixel already is pure black and can't be affected; so what was originally a black pixel in the middle of a dark region becomes a black pixel in the middle of a black region - so you can't actually see it any more: you lose detail in the shadowy areas. And the same thing happens in very bright parts of the picture - there is no longer any visible difference between pure white and slightly greyish white.

Bravia does other things too - for example, if a pixel is (say) a slightly pinkish red (perhaps r240g10b10) it might convert it to a purer red - maybe r255g0b0. That makes the photo's colours seem more saturated. It also does edge enhancement - so if you have an area of dark grey pixels next to an area of pale grey pixels then the dark grey ones right next to the border will be pushed further towards black than the ones that are away from the edge, and the light grey ones right next to the border will be pushed further towards white than the ones that are away from the edge; that makes the edge look sharper. But the important thing to grasp is that all of the things it does involve manipulating the pixels within the image; none of it has the slightest effect on the actual screen. The screen still shows pure black as exactly the same and pure white as exactly the same, and the maximum colour saturation it can achieve is exactly the same; it's simply that the pixels sent to it are pushed further towards the limits of what it can display (with consequent image artefacts).

Those who are hoping for Bravia to be "always on" are also almost certainly in for a dissappointment: Bravia processing is intrinsically part of the process of decoding an image or a video. Asking for Bravia processing to be "on" when you aren't decoding an image or video is a bit like asking for an app that boosts the treble when there isn't any sound - it's not that it can't be done, it's that the request doesn't even make sense.

See, for example, http://developer.sonymobile.com/201...r-viewing-experience-to-the-next-level-video/

(Note that the numbers I'm using here may not be quite realistic: I don't know exactly how bright a pixel has to be before Bravia pushes it up to pure white, for example or how dark it has to be before it comes out black, and in any case that will vary because of edge enhancement; but it changes things in those ways and in those directions).