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noggin12,064 posts since 26 Jun 2001
Quote:
I hope in addition to the revamp that the NOW TV box resolves the stuttering playback issue.


From what I've read NOW TV - like Chromecast - only outputs at 60Hz. That might explain your stuttering if you're watching anything on iPlayer, which would be 25fps and doesn't go well into 60Hz. Some people just don't notice it, though.


It's on everything, from the Sky News and SSN HQ apps, to the NOW TV streams. Some of the live channels are more noticeable than others. GOLD for example has really bad stuttering ,poor lip sync and a grainy picture, while Sky1 is like watching a 544x576 Freeview picture with a low stream.

The LG set I own appears to have none of these issues as it also NTSC compatible.


I think you are missing the point.

All European TV is 50Hz. That means most streaming services in Europe are 25Hz (The BBC have occasionally provided a 50Hz stream for things like the Strictly 3D special - and have 50Hz streams for some other platforms)

The Now TV is fixed at 60Hz, like Chromecast, and the LCD displays of most laptops, iPhones, iPads etc. This means that 25Hz content is displayed at 60Hz - which means frames have to be repeated asymmetrically and you get motion judder that wouldn't be there if you were able to watch at 50Hz. Some people see this, some people don't (and given the huge number of people who watch 25p content at 60Hz on iPhones, iPads, Laptops etc. it doesn't appear to be an issue for many)

If you are using a Smart TV internal app, then the chances are it will display 25p streamed stuff properly at 50Hz - as the the TV will be perfectly capable of running 50Hz (aka "PAL") for Live TV viewing. (NTSC compatibility it irrelevant in this regard - but all EU "HD TV"s have to be 60Hz compatible to carry the "HDTV", "HD Ready" or similar licensed logos)

The major limitation for me for the NowTV box is the lack of a cabled network connection. If you live in a busy built up area, 2.4GHz Wifi is a non-starter for decent speeds, with 5GHz now often getting quite congested (and lots of things are still 2.4GHz only) All my kit is Ethernet connected with the exception of my iPhone and iPad (which are both 5GHz) and my Laptop (when not on my desk - where it is connected to a cabled network connection)
DVB Cornwall6,604 posts since 4 Dec 2003
Westcountry Spotlight
Your phone and PC are designed to cope with 60Hz content. The NowTV/Roku box has to reformat native 50Hz content to 60Hz and then that is reformatted down by your TV, hence the judder. If the NOWTV box was designed exclusively for the UK market it's clock rate would be adjusted accordingly. It's a stripdown of the US Roku device, so the decision was made to leave the up/down conversion in place.
1
dosxuk3,666 posts since 22 Oct 2005
Yorkshire Look North (Yorkshire)
In that case, why am I more than capable of watching 60Hz content on my phone and PC without motion judder, yet it's on my television?


Because (most) European content isn't 60Hz. The NOWTV box is having to create 10 extra fields of information every second in order to play the files at the refresh rate they chose to display it.
It's spelt AERIAL!
1
noggin12,064 posts since 26 Jun 2001
In that case, why am I more than capable of watching 60Hz content on my phone and PC without motion judder, yet it's on my television?


When I watch 25/50Hz content on my laptop, iPhone and iPad I definitely see motion judder. 50Hz native stuff in particular looks terrible. Try watching DVB-T/T2 off-air stuff de-interlaced properly on a laptop, you definitely see the judder, particularly on things like tickers.

Of course 24/30/60Hz stuff looks better on 60Hz displays - so lots of online content not originated for broadcast (and thus shot 24/30/60) looks much better (though you get the normal 3:2 cadence on 24p stuff at 60Hz - which for me is still difficult to watch)

DVD/Blu-ray players will normally switch between 50 and 60Hz (and 24Hz in some cases) output based on the media they are playing (some will even output Netflix at 24p - which makes it watchable, unlike the 3:2 stuff you get on most solutions which output 60Hz instead)

I watch a lot of stuff using XBMC - and have mine configured to change refresh rate dynamically based on the format of the file(s) I'm playing. With the iPlayer, SVT Play, NRK Nett TV etc. plug-ins it does a pretty good job of auto-frame rate switching.
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davidhorman1,573 posts since 8 Mar 2005
Channel Channel Islands
Quote:
(though you get the normal 3:2 cadence on 24p stuff at 60Hz - which for me is still difficult to watch)


Some (most?) TVs can detect this and undo it, though, because it's so ubiquitous in NTSC-land. Not sure if they switch into a 72Hz refresh rate mode, or something.
DVB Cornwall6,604 posts since 4 Dec 2003
Westcountry Spotlight
Problem is it's guesswork, based on the point of which the digital stream is acquired, which frames are dropped, so you can end up with either a perfect solution, or more likely the judder effect. There's no pretty solution where added frames are identified and can thus be dropped neatly.
noggin12,064 posts since 26 Jun 2001
Quote:
(though you get the normal 3:2 cadence on 24p stuff at 60Hz - which for me is still difficult to watch)


Some (most?) TVs can detect this and undo it, though, because it's so ubiquitous in NTSC-land. Not sure if they switch into a 72Hz refresh rate mode, or something.


Most 3:2 cadence detection is for de-interlacing 60i to 60p. If this 60i contains 24p sourced content you end up with a 60i frame containing fields from two different 24p source frames. You wouldn't want to use this frame as a straight weave (as you could with 60i frames containing fields from the same 24p source frame).

So most 3:2 detection is actually there to de-interlace 60i to 24p (by removing the 3:2 cadence in the FIELD structure) and then convert it to 60p by doing a 3:2 repetition in the FRAME domain.

Most sets which do 24p True Cinema or similar (i.e. display a 24p signal at a nice symmetrical 48, 72, 120Hz refresh with 2:2, 3:3, 5:5 etc.) will only do this when fed a 1080/24p signal (or possibly 720/24p) - they won't do it when fed the same signal embedded in a 1080/60i or 1080/60p signal as that would require re-syncing. Would be a nightmare when watching the News or a Clip show where you had a continous mix of 60i native, 24p native and 30p native content intercut.
noggin12,064 posts since 26 Jun 2001
I've never seen 24 into 60 (23.976 into 59.94) be anything other than very straightforwarded and perfectly predictable 3:2 pulldown, and that's easy to identify after a few frames.


Depends how it is edited. If the 24p content is interlaced to 60i with 3:2 pulldown AND then edited in the video domain you can end up with all sorts of nasty cadences on edit points. Not a problem if you edit in the 24p domain - but historically not everybody did.

And then you have the issues where you can have content which contains both 60i native and 24p native content intercut. Often shot by shot. (Imagine a News report shot 60i but also containing film clips sourced 24p. Absolutely standard for a movie publicity junket shoot)
London Lite6,901 posts since 4 Jan 2003
London London
I've bought a Chromecast for £20 as part of the Black Friday sale at Currys/PC World with a 3 month Entertainment Pass, so will give that a go as well.

However I've largely purchased it for the ability to stream from Chrome to the TV.