TV buying advice

[Houses4Rent]

Thanks Andy, sounds like a schlepp to get UHD media. Hopefully it wil become easier in the near future.

You mention DSTV and HD, but would ther source not have to be UHD? So UHD is only via Netflix right now it seems.

I probably will get Netflix and I have a 4 Mb/s copper line (rather call it 3.5 Mb/s). Is that fast enough? Just want to test out of curiousity whether the picture is really that much better.

[irneb]

I'm sorry to hear you got bad experiences from Hisense. Personally I've not had problems with them before. Perhaps yours was just some bad batch, or was damaged while it was demo'd in the shop.

Right ... DVD is (at best) standard definition (SD) tending to be around 480p (i.e. 480 lines of dots across the picture).

FHD (full high definition) is 1080p, more than twice the amount of lines of SD. These sorts of things you only get on BlueRay discs, not DVDs. DSTV's "HD" is in fact "half"-HD, i.e. 720p. Most video recorders (e.g. on a smart phone) tends to record at these sorts of resolutions these days. So most likely your "home-videos" would be at 720p/1080p, long gone is the time of those VHS recorders were the limit.

The 4K / UHD (ultra high definition) is a lot more than that. It may be possible to find some BlueRay discs with this sort of resolution, but they'd be even more scarce than full HD discs. Most likely the only place you'd see this in SA is if you get an online-streamed version or some place you download such video source from (e.g. buying such movie through Amazon). Or of course if you produce such yourself using a video recorder / camera with UHD capability.

It's not a "bad" thing to have a TV which is better than the source files / streams you watch, it's just that you don't use it to its very limits. This may mean the TV needs to scale up lower quality video, or you need to change settings so it doesn't just display as a postage stamp in the middle of the screen. Think of it like someone with a Ferrari only staying at the speed limits on the normal roads, by only ever changing up to 3rd.

It seems a "waste", but what would be your alternative? Paying more for something worse? As long as it's nothing extra out of your pocket, I'd say go for the 4K TV. Even if you're never going to use it to its maximum, it's not as if it cannot show even old PAL qualities at 180 lines per screen (i.e. like TV signals in 70s and 80s), so your old DVD player should still work the same on a UHD as it would on a FHD or 1/2 HD or SD capable TV.

It's just that the TV uses 2 or more of its lines to display a single line from the DVD (i.e. it gets scaled up). And because the lines are so close together, it's highly unlikely you'd notice any artefacts due to the scaling process - though I'd likely want to see it first (ask them to play a DVD through it for you).

[Houses4Rent]

Thanks irneb, that makes sense. FYI the TV is in my lounge already and I did not pay extra for the "upgrade". So HISENSE did come to the party in the end.
Its a quantum leap jump for me as I came from a 54cm (yes, cm) CRT to a 50 inch LED flat screen UHD, lol

[irneb]

Thanks Andy, sounds like a schlepp to get UHD media. Hopefully it wil become easier in the near future.

You mention DSTV and HD, but would ther source not have to be UHD? So UHD is only via Netflix right now it seems.

I probably will get Netflix and I have a 4 Mb/s copper line (rather call it 3.5 Mb/s). Is that fast enough? Just want to test out of curiousity whether the picture is really that much better.

For UHD that speed's a bit on the low side. You'd most likely need lots of buffering to get something playing decently across that. Or more likely be able to download the file before you start watching.

You're effectively on the limits for halfHD / interlaced fullHD (i.e. 720p / 1080i), 1080p should be fine over 5Mb/s or higher, though SD (DVD quality) should be quite decent across that (a 1Mb/s is around your bottom limit for such). But for UHD I'd say you require at least 10Mb/s, probably better at 15. Note, these are if the compression techniques used are "decent", e.g. using multi-pass H265 encoding (or something similar, I think NetFlix did say they're going with H265 these days). Else you either need much higher baud-rates or you're going to see block-artefacts, dropped frames, stuttering, etc.

Thanks irneb, that makes sense. FYI the TV is in my lounge already and I did not pay extra for the "upgrade". So HISENSE did come to the party in the end.
Its a quantum leap jump for me as I came from a 54cm (yes, cm) CRT to a 50 inch LED flat screen UHD, lol

You're welcome ... yes it is a leap isn't it! I've also experienced similar myself, I find even my 24" LCD monitor to feel larger (never mind clearer) than my old CRT TV. But the LED TV is simply way beyond what I used to experience (even though it's just FHD).

[AndyD]

Thanks Andy, sounds like a schlepp to get UHD media. Hopefully it wil become easier in the near future.

You mention DSTV and HD, but would ther source not have to be UHD? So UHD is only via Netflix right now it seems.

I probably will get Netflix and I have a 4 Mb/s copper line (rather call it 3.5 Mb/s). Is that fast enough? Just want to test out of curiousity whether the picture is really that much better.

I'm not even remotely clued up about DSTV, I've not been a subscriber since they told me there was some kinda charge to have it suspended and reconnected during and after some building work at home so I told them they could shove it and I never looked back. They do have some info about HD channels on their website

A 4 meg line might be a problem for HD streaming, I'd do some real life speed tests on the line before taking the plunge. Also make sure it's unshaped and unthrottled etc.

[AndyD]

For UHD that speed's a bit on the low side. You'd most likely need lots of buffering to get something playing decently across that. Or more likely be able to download the file before you start watching.

You're effectively on the limits for halfHD / interlaced fullHD (i.e. 720p / 1080i), 1080p should be fine over 5Mb/s or higher, though SD (DVD quality) should be quite decent across that (a 1Mb/s is around your bottom limit for such). But for UHD I'd say you require at least 10Mb/s, probably better at 15. Note, these are if the compression techniques used are "decent", e.g. using multi-pass H265 encoding (or something similar, I think NetFlix did say they're going with H265 these days). Else you either need much higher baud-rates or you're going to see block-artefacts, dropped frames, stuttering, etc.

The terms HD and UHD are nasty and misleading. HD refers to anything that's 1080p resolution, the problem is even a movie that's been 'upscaled' to 1080p from a 720p source would still qualify as HD even though the quality will be poor. Likewise the term HD takes no account of the bitrate of encode so you will find mkv containered HD 1080p movies that range between 1.6 gigs and 50gigs in size and again the playback quality will be poorer for the small file even though both are technically 1080p resolution.

I'm not sure what standard netflix encodes follow or what filesizes HD and UHD movies would be so I can't comment on ADSL speed requirements. They do have a guide on their website though.

[irneb]

The terms HD and UHD are nasty and misleading. HD refers to anything that's 1080p resolution, the problem is even a movie that's been 'upscaled' to 1080p from a 720p source would still qualify as HD even though the quality will be poor. Likewise the term HD takes no account of the bitrate of encode so you will find mkv containered HD 1080p movies that range between 1.6 gigs and 50gigs in size and again the playback quality will be poorer for the small file even though both are technically 1080p resolution. But down scaling from UHD to FHD (or even lower) isn't a bad idea at all.

I'm not sure what standard netflix encodes follow or what filesizes HD and UHD movies would be so I can't comment on ADSL speed requirements. They do have a guide on their website though.

You're right about upscaled being a "silly" idea. You cannot make something better than it used to be by increasing its resolution. So if the movie wasn't recorded at FHD (usually they're recorded in RAW uncompressed format, these days at typical 4K resolutions at anywhere between 24 and 60 fps - meaning multi-TB files), then turning it into FHD is a futile exercise.

And yes, the smaller file is probably worse than the larger. All other things being equal. However, a smaller file with a better compression codec might even be better than a larger file with a less optimized codec. It all comes down to the amount of loss in the lossy compression used in the codec. E.g. some would throw away certain colour shifts which human eyes cannot distinguish, others may combine similar pixels, yet more may combine portions of consecutive frames which they deem not to change, and some of the later versions also try to figure out movements from frame to frame. It's usually a bad idea to push these to their limits.

Personally, I've done some re-encodings myself. And what I've found is best results (both minimum file size and best quality) tend to come from using the better variants of compression codecs (used to be xvid, though these days VP8/H265 give even better results), using a multi-pass encoding (checking how much loss will happen and reducing the loss to acceptable levels in final pass), and never use a constant bitrate encoding scheme (rather allow increased bitrate for scenes where it's needed and reduced where it's not). Unfortunately, this means a 2h movie of 1080p@24fps could be fine at 2GB, while another of similar length, resolution and framerate may start to show artefacts at 5GB. It is usually a factor of how much movement and complex shapes are changing between frames. Increasing the resolution tends to mean a multiplicative increase in size as well, e.g. 1080 to 2160 is not just twice as large, but rather 4 times (i.e. the pixel count is the effect, not the height) - though that's also an inexact measurement due to the actual compression algorithm. It's possible to derive the statistics of how much an encoded file deviates from the original, and this is where multi-pass encodings comes in, it uses such statistics to figure out which parts of the movie requires higher bitrates and which can be made even lower. My own investigations showed that best results is obtained by using a constant quality limit with multiple pass encoding and a variable bitrate, as soon as a constant bitrate is forced the quality suffers.

I'm not exactly sure just how NetFlix encodes their FHD/UHD movies, or others for that matter. They tend to keep the exact "science" behind these a secret (from each other at least). The trouble is bitrate on its own (i.e. the size of the file delivered) is only a part of the story. The compression algorithm and how it's applied tends to have a bigger effect on the quality than the file size, and the actual raw material (i.e. the original recording) has the greatest effect. Some reading material:

http://www.imore.com/netflix-increasing-compression-so-why-isnt-apple

http://mdp-labs.co/netflix-leads-with-superior-compression-algorithms/

https://donmelton.com/2015/12/21/what-the-new-video-compression-strategy-from-netflix-means-for-apple-and-amazon/

http://variety.com/2015/digital/news/netflix-better-streaming-quality-1201661116/