Do blu-ray players really differ in picture quality?

[torarin]

Usually tests claim that this or that player has a "razor-sharp" picture or "minimal distortion in moving scenes" in comparison to other, cheaper players.
This makes no sense to me.
I don't want players to "sharpen" the image and I thought deblocking algorithms were written in stone in the h264 and VC-1 standards.
Does anyone get this?

[nurbs]

They should all give exactly the same picture (at least for AVC and VC-1; not sure about Mpeg-2) unless they use some kind of postprocessing. If they do then I hope you can turn it off, because I've had some negative experiences with the "image improvement" filters that my new TV set had on by default. The default settings on this thing completely killed all details in the picture.

[torarin]

Yes! :) That's exactly what I'm thinking. If they do "picture enhancement" the reviewers shouldn't be bragging about it. That's what is so strange. Mpeg-2 will still need player-defined deblocking of course.

[setarip_old]

@torarin

The advertising you've quoted sounds more like what you read about TVs and/or monitors - and some players' upconverting capabilities regarding standard DVDs...

[Blue_MiSfit]

Well, there are some small subtle differences, assuming you're using HDMI.

Basically HDMI doesn't allow carrying YV12 (4:2:0). So, the player must upconvert to 4:2:2 or 4:4:4 - OR RGB in some cases. This involves outputting higher than 8 bits per channel, and then dithering back to 8 bits, since "deep color" HDMI isn't supported by many TVs. There are many algorithms to do this, some better than most.

Honestly, the differences are quite small, and most folks (even well trained videophiles that usually hang out here) would be hard pressed to notice them.

For interlaced content, it's another story entirely. Deinterlacing is an extremely complicated problem, and there are many many ways of doing it, each with their own advantages. This is the biggest thing differentiating BluRay / DVD players. Of course, you can output a 1080i signal and let the TV deinterlace, but that can sometimes be bad news as well.

The same holds true for DVD playback, with the added complication of upscaling. Anything from simple bilinear / bicubic interpolation can be used, or in the better players, some form of edge-directed interpolation.

The very best solution is to have a dedicated (expensive) video scaler which adaptively chooses between several high quality algorithms (with manual override possible, of course) to perform deinterlacing and color conversion.

To sum it up though - 90% of people interested in BluRay would be quite happy (picture-quality wise) with the cheapest BluRay player they can get their hands on! Leave the uber expensive stuff to those with deep pockets who don't mind spending a ton to get that extra 10% of image quality ;)

~MiSfit

[torarin]

Thanks, you are right about interlacing and DVD upscaling.
So regarding AVC and VC-1, only the quality of the color upscaling depends on the player?

[thewebchat]

As far as chroma upsampling goes, even something as trivial as bilinear scaling is more than enough, seeing as humans are pretty much colorblind anyway.

[Blue_MiSfit]

Yeah. The various decoders (damned well better) give identical output.

So, if you're talking usual 1080p content, without any silly processing, you won't see much if any difference between different BluRay players.

Now, UI and overall performance is a big factor for me. I'd suggest you try out some BluRay players to see how the menu systems / remote work. Nothing worse than good hardware handicapped by a half-baked interface or laggy input!!

~MiSfit