How good is HD supposed to be?

Sat Apr 30 09:38:55 PDT 2016

Vieras are nice. Perhaps your panel is doing frame rate interpolation, 
where it upconverts low frame rate source material to high frame rate for 
display. This is something panels which can operate at higher refresh rates 
offer (100 Hz, 120 Hz, 200 Hz etc).

This is also something I immediately turn off if I'm ever setting up a 
screen, because it makes everything look like a soap opera and annoys me 
after a while (unless it's true high frame rate source material, like The 
Hobbit HFR).

Check in your options for something like 'True Motion', 'Cinema Smoother', 
Motion Estimation / Motion Compensation... And turn it off. Manufacturers 
call it various nonsense marketing names including 'Truemotion Plus', 'Auto 
Motion Plus', 'ClearFrame' etc. Essentially it's pulldown, and it's not the 
original picture, and I don't like it. ;)

Often the chipset doesn't get it quite right, or it gets confused with 
picture content, and you can end up with the option smoothing suddenly 
stopping - or kicking in - midway through a camera pan or actor moving 
slowly in a scene, which is incredibly jarring.

Also (depending on your panel options) set local dimming off, turn 
brightness down to about halfway, turn contrast to about 3/4 and set your 
colour balance or screen temperature to 'warm' or 'warm 1' (usually much 
closer to the calibrated D65 reference white used in broadcast). Almost 
every TV I've ever seen is FAR too blue out of the box on its defaults. Set 
Sharpness to as low as possible, on almost all screens this is ADDITIONAL 
sharpness and makes everything look foul. Your eyes will thank you!

Cheers
Chris

On 30 April 2016 2:23:40 p.m. "Simon Morgan" <s.morgan at skm.org.uk> wrote:

> Thanks for your helpful explanation. Demystified a few points for me. I have
> a new Panasonic Viera (is this "high end"?) and I find the 25fps from my GiP
> downloads more than adequate - perhaps because I know no better!
> RGds
> Simon Morgan
>
> -----Original Message-----
> From: get_iplayer [mailto:get_iplayer-bounces at lists.infradead.org] On Behalf
> Of Christopher Woods
> Sent: 29 April 2016 20:42
> To: Dave Lambley; Dave Liquorice
> Cc: Get_iplayer List
> Subject: Re: How good is HD supposed to be?
>
> "Upscaling" is a misnomer in this context. That implies a change of picture
> resolution, when there's no resizing going on. What iPlayer does for the 50p
> streams is double frame rate deinterlacing, using what looks like a bob
> deinterlace technique.
>
> If you watch content originated in 25i, you will (once the stream steps up
> to 720p50) see the deinterlaced 50p content and you'll notice immediately
> how fluidic motion is - "just like TV", because that's exactly what CRTs
> used to do.
>
> 25 interlaced frames per second yields 50 interlaced fields per second (due
> to odd and even line scanning), with the resultant persistence of vision
> effect inducing a pseudo 50 frames per second on viewing as each field's
> worth of capture by the camera sensor 'sees' a slightly different point in
> time. This renders as smoother motion, with a slight loss of sharpness due
> to the low overall temporal resolution, but as it overall appears more
> lifelike the eye prefers it.
>
> 25psf (progressive segmented frames) is the "filmic" look, where there's
> only 25 distinct 'captures' of motion per second; the video simply
> 'transported' as interlaced. Each field 'sees' its half of the same source
> frame. When decoded properly, you get 100% progressive output. However as
> this gives you half the temporal resolution, motion is visibly less fluid.
>
> Modern flat panels all deinterlace all interlaced source material to display
> a progressive image, but only the higher end panels do quality deinterlacing
> (Yadif or similar) Cheaper screens will usually bob deinterlace
> (computationally less demanding) and porbably convert to 60p as their panels
> and processing will be running internally at 60Hz.
>
> You can even spot some cheap screens doing this as they'll add or duplicate
> frames periodically to equal 60 fps from 50 fps source material, or they'll
> do weird interpolation which can result in jumpy credits or news ticker
> scrolling artifacts.
>
> For an example of 720p50 iPlayer content, watch any episode of EastEnders
> (be sure to enable HD), full screen it and wait for the bandwidth to step up
> to max - you'll need 5 megabits per second minimum to stream (... Or just dl
> it with gip).
>
> For an example of progressive scan material, just about any documentary
> (e.g. Horizon) or episode of Click will do. The latest Horizon about dating
> is 25 PsF: you can see the deinterlacing 'interline twitter' on high
> contrast edges during the programme - an example being the leaves of the pot
> plant moving on the windowsill at around 22 minute mark.
>
>
> On 29 April 2016 12:44:31 p.m. Dave Lambley <dave at lambley.me.uk> wrote:
>
>> On 29 April 2016 at 00:57, Dave Liquorice <allsorts at howhill.com> wrote:
>>> On Thu, 28 Apr 2016 07:07:33 -0500, artisticforge . wrote:
>>>
>>>
>>>>>> NB hvfhd DOES NOT OFFER HIGHER RESOLUTION (CLARITY), only doubled
>>>>>> framerate (25FPS x2), which results in smoother scenes where
>>>>>> motion is involved!
>>>>>
>>>>> How does repeating frames improve smoothness of movement? Or does
>>>>> this encode upscale each field(*) and encode that to increase the
>>>>> temporal resolution?
>>>>
>>>> It is the frames per second that provide the human eye with the
>>>> persistence of vision, the illusion of motion.
>>>
>>> I could show you 100 fps but if there where only 4 different images
>>> displayed the illusion of motion would be no smoother than 25 fps.
>>> You only get smoother movement by increasing the number of different
>>> images displayed.
>>>
>>> So if this hvfhd only repeats each frame to get a higher frame there
>>> is no increase in smoothness. How ever if they take each field,
>>> upscale it and encode as a frame that would inrease the smoothness.
>>
>> I believe the frame repeating idea is a red herring. Real 50 frame/s
>> computer video is a thing which exists. If your browser's up to it you
>> can see for yourself here, https://www.youtube.com/watch?v=PmNapQdWFKg
>>
>> You'll need to choose one of the "p50" resolutions on the Quality menu.
>>
>> Dave
>>
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>
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