[mythtv-users] FE upgrade to support 4k TV

[Andre Newman]

On 17 Nov 2014, at 17:23, Peter Buelow <goballstate at gmail.com> wrote:

> Hello, I've been doing some research about this, and want to know what people think about migrating to a 4k TV, specifically with respect to Myth. Mostly I know there isn't much 4k content yet, but I don't upgrade often, so I want to get something that will be relevant for 7-10 years (assuming the device lasts that long). I see several threads related to this question (some 2 years old), but I can't find anyone who has just asked directly about migrating a Myth setup to 4k and what problems and challenges go with that. It's a basic FE setup, connected to the TV through a fairly new Onkyo receiver (TX-NR616). The receiver claims to support 4k for compat TV's, but I haven't verified/tested that yet. I hope I can reuse my current home theater setup without a lot of changes.
> 
> Specific questions.

I work in sports TV, I work on some UHD transmissions, not 4k of course that’s a Digital Cinema format but some projectors and some TVs can do 4k and UHD, most “4k” TVs are UHDTVs.
> 
> 1. I keep reading in several threads that 4k decoding might be changing before long.

It changed already from 8bit to 10bit, I didn’t see much 10bit until this year. BBC said that most equipment didn’t work properly with 10bit so they broadcast the World Cup tests in 8bit, Commonwealth Games was 8 bit until the last day. Most (all maybe) current TV panels are 8 bit, some are 6 bit with FRC.

I see a lot of changes in what the encoder guys produce, everything is different, every transmission, every month or two. I find that different TV decoders get better or worse with each firmware update and each transmission encoder update, big difference between the manufacturers too.

Kodi (sorry) is keeping up quite well but transmissions from today play with old nightly builds but not current beta, it’s a difficult thing to keep up with. Remux to h265 in mp4 plays ok, 20fps on 2.66Ghz i7 macbook pro, was 6fps with alpha 1.

> Is this an h.265 problem? Will changes to specs mean any 4k TV is hobbled at best in a year or two?

Probably, all the sports broadcasters are saying that p50 is not enough, they want to try p100. None of the current panels can manage more than p60, IMO none can really do even p60 yet, Samsung 9000 series is close. This is just the frame rate there are other aspects, dynamic range, colour space etc.

Where I am working today they have a Sony 900a UHDTV, if you give it a modern h265 stream to decode it reboots, Sony say there is no fix, already this expensive TV is junk.

Japanese recorded two World Cup games in 8k at 120p, it looks pretty good but not much to add over 4k, 120p looks ok not so amazing until you then go watch some 60p or 60i and then you realise how good it looked, same effect at 1080p120 or 720p120. I have see some 1024x768 at p300 and that looked totally stunning, like an open window. 

> Or can decoders be upgraded? They said the same thing about HD changing and screwing early adopters long ago, but that didn't amount to much that I remember.

Ask any early adopter about their UK Sky HD, it stopped working a few months ago. Any early HDTV has only component inputs, only the Thompson Sky box had component out and Sky don’t allow HD channels on that box any more.

> I see ffmpeg work related to this though, so maybe I don't care?
> 2. I know Myth on it's own will work fine in 4k,

For H264 4k works now and maybe H265 in software in 0.28?? Maybe, maybe not. There are no longer any 4k transmissions in H264, even the old test channels have gone. There are 3 channels transmitting FTA in Europe for demos and tests, also one encrypted.

> but do I need bleeding edge Nvidia and new cabling for video playback,

Yes, only 970 & 980 cards have HDMI 2.0 but there are very few reports of success, even in Windows, Linux I don’t know yet. Maybe I will have one soon to test. There are many TVs that say HDMI 2.0 but it’s HDMI 1.4 with HDMI 2.0 signalling so there isn’t enough bandwidth for full frame rate, ok for 24p movies but nothing else, not even for de-interlaced 1080i, you need 50p of 60p for that and full resolution for good scaling quality.

But be warned Nvidia said only partial h265 support in VDPAU you will still need a reasonable CPU for H265, Atom is not a reasonable CPU.

> or can I live with my current card/cables and make all video resolutions work? The setup is currently a GTX 460, AMD 64 bit something or another (at least 5 years old, pry older, see below), and standard HDMI cabling. I watch FOTA TV in HD on it streaming (GbE) from a dedicated BE, plus several hundred of my movies transcoded using Handbrake for easy access streaming from the same BE.
> 3. I'll transcode any new content to 4k (why not?)

Because it’s crazy, that’s why not, h265 encoding is very hard so takes a long time, oss encoding is very poor, closed source encoding is very poor! So probably you will end up with a small space saving and a lower quality after many days CPU time encoding. My 4Ghz Haswell takes a long while to encode...

> if/when Handbrake supports, plus we do a lot of 4k video recording of my daughter because our phones/cameras support it, so mostly this effort is to support that for now. Will Myth have issues, and will I have to build the SW on my own, or should it work out of the box on the latest Fedora using yum (rpmfusion built version)?

If it’s h264 and you have fast enough cpu or vdpau with 6xx card then it works now, mine does, did last time I looked, 0.27 fixes on Ubuntu.

> 
> My plan is to do a wholesale FE update for new capabilities. My current setup is fairly old cause it just works. The only big changes in the last 8 years are a new Nvidia card and a new flash drive. So I'll do a new MB/CPU/RAM/Video(?) but same case (Antec Silver I love). Mostly, I want to see if I can't get another 8-10 years with minimal changes like before.

Then you need to wait until the video standard settles out, the REC2020 proposals cannot be achieved with current display technology, maybe laser projection next year, maybe quantum dot or OLED in a few years, maybe never and we decide to go to DCI P3 instead.

This not like HD, first HD truck was in Brighton in 1988, I got a tour but HD is still not standard yet, UHD development is much quicker and everyone is watching, broadcasters know this. One big sports TV hire company I know just ordered 20 UHD cameras.


> What started this was my wife promised we could buy a new TV for the Super Bowl a year ago, so I think I want to go 4k now as it's not that much more expensive. Plus, we keep our TV's for a long time. The unit being replaced is a 47 inch LG that is almost 8 years old now. And I like the 70" Vizio at Costco a lot.

The Vizio’s are pretty crap but the price is ok for those who want to play, unless something changed they can’t do 50p or 60p so only movies, no sport. You can feed it with 1080p but then there is less benefit.

I find that 55” needs to be viewed from 1m away to see the benefit of the extra resolution. I have a 110” projected 1080p screen at home and I’m not worried about upgrading anytime soon.

The Sony guys say there is a massive benefit watching on a tablet because people hold them close, apparent screen size is better than even 85” TV at normal viewing distances.


> Samsung had one on display at Best Buy as well that I thought was visually outstanding though much more expensive.

The Samsungs are the only ones worth looking at but often you will get a better picture on a 1080p set.

> 
> Thanks for any help and suggestions.

There is a Samsung sponsored concert transmitted Wednesday night from Munich, if the equipment works properly…

Andre

> 
> -- 
> Pete
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