4K on 1080 screen - Prime vs iTunes.

[Drooch]

When I stream Amazon Prime 4K UHD movies from my Apple TV to my 1080p plasma it looks AMAZING, I can do direct comparisons of, for example, Ghostbusters II in HD and UHD and the difference is drastic. Clearly it’s downconverting the UHD for my screen, much like my 4K player does.

However, when I play 4K movies bought on iTunes it just plays the old 1080p version, which looks meh. Does anyone know why this is, or if there’s a workaround to get the superior 4K version squeezed down?

Also, if I were to get 4K Netflix, would it stream downconverted 4K UHD versions, or just the inferior HD versions?

Thanks in advance.

[Fiffy]

The Apple TV automatically selects the 1080p stream if you don't have a 4K-capable device connected. The only way to prevent that is to connect something to the HDMI port that can process 4K (and downscale for the display if necessary), like e.g. an AVR or an HDMI splitter with downscaling capability.

I'm suprised that Amazon apparently does not do that. Can you actually select between HD and 4K versions in the Amazon app?

That said, if you see a night-and-day difference, my guess would be that the HD version is based on an older master than the 4K version. Otherwise it should not make such a big difference on a 1080p plasma, given that it cannot utilize HDR, wide color gamut or increased resolution (you'd only benefit from better chroma resolution and potentially better compression of the 4K stream). In many cases the colors of a 4K/HDR image that is downscaled to HD/SDR will look off, since tone mapping and color space mapping have to be performed (which are lossy operations).

[SpaceBlackKnight]

|AppleTV plays a SDR 1080p version of a 4k title, which is almost always based on the same source as the remaster. For Amazon Video, if you have a UHD only title/rental and play it on a non-4k SDR device, it will play a downsampled 1080p version of it.

Vudu is different and kinda a PTA. If it's a brand new release 4k title like say Trolls World Tour, Vudu will tell the device to output the SD/HDX version to non-4k HDR displays. Titles like these always have downconverted SD and HDX versions based directly off it.

However, say if Vudu has an older title that recently added a 4k purchase option, they don't always change out the master for SD/HDX versions with it (unless it's a different cut or new listing entirely, which is extremely rare). The Santa Clause 4k on Vudu only plays the 4k master (which is an edited version, more on this later) on a certified 4k HDR device and display. It has SD and HDX options, but they're definitely not based on the 4k master. Vudu still left them on an older HD master, which has a scene that was edited out of most versions since 1996:

Quote from Wikipedia:

"At one point of the film a brief exchange between Scott and Laura takes place in which Laura hands Scott a piece of paper with Neal's mother's phone number on it. Scott then says "1-800-SPANK-ME. I know that number." In the United States, the exchange was removed from all home media releases of the film except for the VHS releases and most digital downloads starting with the 1999 DVD release after a 1996 incident in which a child from Steilacoom, Washington called the number (which turned out to be an actual, working sex line number) and incurred a phone bill of US$400 (equivalent to $652.07 in 2019).[15"

[Drooch]

Originally Posted by Fiffy

The Apple TV automatically selects the 1080p stream if you don't have a 4K-capable device connected. The only way to prevent that is to connect something to the HDMI port that can process 4K (and downscale for the display if necessary), like e.g. an AVR or an HDMI splitter with downscaling capability.

Thanks, can you give examples of what those things are? Maybe I’ll get hold of one.

I'm suprised that Amazon apparently does not do that. Can you actually select between HD and 4K versions in the Amazon app?

No, you can choose to rent/buy UHD or HD versions. The UHD is a very good downscale (much like my 4K player which does an excellent job of downscaling), the HD is some crappy old master.

[Fiffy]

Originally Posted by Drooch

Thanks, can you give examples of what those things are? Maybe I’ll get hold of one.

Many 4k-capable AVRs can downscale 4k to 1080p. There are also HDMI scalers like this one:

https://sewelldirect.com/products/ec...ler-downscaler

I don't know how good or bad this particular model is in terms of image quality though. I also used to have a 1:2 splitter that could downscale 4K, but can't find it anymore. Just be careful when shopping because many splitters that claim to "downscale" just manipulate the HDMI EDID data to force the source device to downscale, which is not what you want to achieve in this case.

[SpaceBlackKnight]

Originally Posted by Fiffy

Many 4k-capable AVRs can downscale 4k to 1080p.

Do you know which models in particular? Very interesting as I hear the vast majority of receivers just pass through a 4k signal and if your TV isn't 4k, it displays an error message.

[Fiffy]

Originally Posted by SpaceBlackKnight

Do you know which models in particular? Very interesting as I hear the vast majority of receivers just pass through a 4k signal and if your TV isn't 4k, it displays an error message.

E.g. the Yamaha RX-A1080 and up or the RX-V685.