[mythtv-users] nvidia card for 4k display

[Andre Newman]

On 15 Sep 2014, at 00:08, Nick Rout <nick.rout at gmail.com> wrote:

> On Sun, Sep 14, 2014 at 10:58 PM, Jean-Yves Avenard <jyavenard at gmail.com> wrote:
>> 
>> 
>> Le dimanche 14 septembre 2014, Nick Rout <nick.rout at gmail.com> a écrit :
>> 
>>> On Sat, Sep 13, 2014 at 7:39 PM, Jean-Yves Avenard <jyavenard at gmail.com>
>>> wrote:
>>>> On 13 September 2014 14:09, Evuraan <evuraan at gmail.com> wrote:
>>>>> Hello list!
>>>>> 
>>>>> I would like to get a 4K display, and wanted to see if any who went
>>>>> that route  would kindly recommend a decent nvidia card capable of 4K.
>>>>> (Most of my content is OTA, >=1080, and currently using a GT430
>>>>> despite a failed fan!)

I have a GT640 which I can confirm will play h264 4k and UHD (3840x2160) at 24fps and 30fps, I don’t have any 4k or UHD videos in h264 at 50fps or 60fps, in fact I don’t think the appropriate H264 levels support the higher frame rate.

I don’t have a 4k monitor (yet) but the card is capable provided you get the version with the correct output port (currently only displayport) playing downscaled to 1080p is actually more work for the card than driving a full resolution display.

You may wish to wait a few weeks and get a second generation Maxwell card as they are supposed to have some acceleration for hevc (h265) and most 4k UHD material will be encoded with hevc. MythTV does not have official support for hevc yet but I saw that the code in ffmpeg is merged in master so hopefully at least software playback will come in the next release, I expect that even if VDPAU gets extended for hevc it will require significant work from MythTV devs to make use of it, especially as it is reputed to be partial support.

Hopefully there will be some second gen Maxwell cards with HDMI 2.0, you must be careful with HDMI 2.0 as there are two implementations (mostly Sony messing around) one is really HDMI1.4 with 2.0 signalling and this is only good for 4k at 30fps or a special UHD at 50 or 60fps with 4:2:0 colour, this is just about ok for TV but very poor for desktop and graphics. You need the full bandwidth HDMI 2.0 to drive a 4k or UHD display at 50fps or 60fps and 4:4:4 colour.

I find that a very serious CPU is needed for hevc 4k/UHD playback at 50fps or 60fps, I have an overclocked i7 4790k and at 4.7Ghz it’s just enough for 50fps. There is frantic development in ffmpeg for hevc performance as many set top box and video monitoring equipment manufacturers make use of it or portions of the code, a couple of them owned up to this to me at the weekend.

It’s a minefield right now, never mind that the UHD/ 4k standards are set at a point which will change rapidly in the next couple of years obsoleting almost all current “4K” TVs and monitors… HDR,maybe BBC system, maybe Phillips, maybe Dolby, HFR I saw UHD at 100fps (2160p100) and even 8k at 120fps from the world cup.

I just came back from IBC the broadcast trade show which is wall to wall UHD TV.

happy to clarify any of the above if needed and I’ll be getting a Maxwell card as soon as they are readily available.

Andre


>>>> 
>>>> I'd love to know what content you have that would fit the > 1080.
>>>> I can understand == 1080, but greater than that?
>>>> 
>>>> At this stage, if the screen is dedicated to mythfrontend, 4K is a total
>>>> waste
>>> 
>>> 
>>> 
>>> So will mythfrontend not pay back 4K material? I understand there have
>>> been transmissions in the UK (World Cup time as I understand).
>>> 
>> 
>> If you have the processor or video card for it, it will of course...
>> Vdpau only supported > 2048 width or height in feature set D and later
> 
> Thanks, I thought that should be the case. For those who aren't aware,
> Feature sets can be found in the nVidia README,, eg
> 
> http://us.download.nvidia.com/XFree86/Linux-x86_64/340.32/README/supportedchips.html
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