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Re: shooting LED wall - banding and sawtooth artefact

Andy Jarosz
 

Just stumbled across this thread, but may have some input. Refresh rate is not actually as important in LED walls as the scan rate is.

LED panels are capable of a much faster refresh than camera shutter speeds, so as long as you’re genlocked, that will be no problem. However, the scan rate of the panel, expressed as a fraction such as 1/12, 1/16, 1/32 etc. shows what percentage of the screen is lit up at any given time. If this number is too low, the shutter of the camera will catch the screen mid-refresh, and you’ll see artifacts. In general, you want a scan rate of 1/12 or better (1/8 is the best I’ve seen, from Silicon-Core.)

This effect is not necessarily a factor for in person viewing, so the vast majority of LED panels don’t optimize it, and many manufacturers don’t even list it in the specs. It’s also a fundamental relationship between the panel, shutter speed, and camera sensor read speed, which means if you’re stuck with that display, you may be out of luck unfortunately.

-- 
Andy Jarosz
MadlyFX Special Effects & Props
Andy@...
708.420.2639
Chicago, IL


Re: Resolution, was 8K Samsung TVs

Bob Kertesz
 

I'm pretty sure my Mikrotik measured 14 Mbits per sec. Are you saying
Mbytes..? Thats 100-160 Mbit, which is indeed a lot.
That was a typo, or else my spell checker 'helping' me. It was supposed
to be megabits, of course.

-Bob

Bob Kertesz
BlueScreen LLC
Hollywood, California

Engineer, Video Controller, and Live Compositor Extraordinaire.

High quality images for more than four decades - whether you've wanted
them or not.©

* * * * * * * * * *


Re: Resolution, was 8K Samsung TVs

Video Assist Hungary
 


On 2019. Nov 4., at 23:15, Bob Kertesz <bob@...> wrote:
UHD from both Amazon Prime Video and Netflix at between 13 and 20 MB/s, 
I'm pretty sure my Mikrotik measured 14 Mbits per sec. Are you saying Mbytes..? Thats 100-160 Mbit, which is indeed a lot. 

Netflix lists the following on their playback settings:
Low: 0.3GB/hour = 2400 Mbit/hour = 0,66 Mbit/s
Medium: 0.7 GB/hour = 5600 Mbit/hour = 1,55 Mbit/s
High HD: 3GB/hour = 24 000 Mbit/hour = 6,66 Mbit/s
High 4K: 7GB/hour = 56 000 Mbit/hour = 15,55 Mbit/s

I'd guess all the streaming services are around this.

compare the 15,5 Mbps with a Mini @arriraw 4k (1351Mbps) and @prores444 (300 Mbps) 
when I used to do DVDs there were around 5Mbps for SD. a BluRay is 25-50 Mbps for HD. 

those numbers are all with audio.

Balazs Rozgonyi 
CEO Video Assist Hungary


Re: Resolution, was 8K Samsung TVs

Bob Kertesz
 

With HEVC and someone who knows what he or she is doing, they may be
able to send an artifact free stream of UHD at 14mb/s.  Not sure what
the true measured resolution would be.
I use the older 2nd generation Amazon Fire box, and get artifact-free
UHD (with or without various HDR formats and enhanced audio encoding)
from both Amazon Prime Video and Netflix at between 13 and 20 MB/s,
according to the Fire's double secret diagnostics screen. Those are the
two UHD streaming sources I have here.

My LG OLED says the incoming resolution from the Fire box is full UHD
from those sources.

-Bob

Bob Kertesz
BlueScreen LLC
Hollywood, California

Engineer, Video Controller, and Live Compositor Extraordinaire.

High quality images for more than four decades - whether you've wanted
them or not.©

* * * * * * * * * *


Re: Resolution, was 8K Samsung TVs

Video Assist Hungary
 

Maybe Dolby Vision should have some constraints/recommendations on the bitrate and codecs..

Balázs Rozgonyi
CEO
Video Assist Hungary


Re: Resolution, was 8K Samsung TVs

Robert A. Ober
 

Video Assist Hungary wrote on 11/4/19 12:26 PM:


Robert A. Ober wrote:
What device were you using to watch?
The newer AppleTV 4K 

Any idea which codec they are using?
No, but I’d hazard a guess that the aTV has a HEVC hardware decoder. 
––––––––––––––––––––––––––––

Yes it does have HEVC.  I have an AppleTV 4K as well.  With HEVC and someone who knows what he or she is doing, they may be able to send an artifact free stream of UHD at 14mb/s.  Not sure what the true measured resolution would be.

Thanks:-)


Re: Resolution, was 8K Samsung TVs

Video Assist Hungary
 


Robert A. Ober wrote:
What device were you using to watch?
The newer AppleTV 4K 

Any idea which codec they are using?
No, but I’d hazard a guess that the aTV has a HEVC hardware decoder. 

 The Apple TV 4K supports H.264, HEVC (H.265), HEVC Dolby Vision, and MPEG-4. As for photos, it can display images in the following formats: HEIF, JPEG, GIF, and TIFF.”

Balázs Rozgonyi
CEO 
Video assist hungary


Re: Resolution, was 8K Samsung TVs

Robert A. Ober
 

Bob Kertesz wrote on 11/1/19 5:49 PM:

I have yet to hear a DP say "Y'know, I'd love to shoot in 8K because
shooting at the current 6.5K just doesn't give the people who deal with
my footage in post nearly enough latitude to fuck up my framing."
LOL

Love some of your posts!

Robert A. Ober

IT Consultant, Vidcaster, & Freelance Preditor(Producer/Editor)
www.infohou.com
Houston, TX



Re: Resolution, was 8K Samsung TVs

Robert A. Ober
 

Video Assist Hungary wrote on 11/1/19 10:00 AM:

Just FYI. I’m watching the today-opened streaming service AppleTV+, in Central Europe, on cabled net. My 4K hdr Dolby vision stream is measured by my Mikrotik router at 14Mbps.
––––––––––––––––––––––––

What device were you using to watch?

Any idea which codec they are using?

Thanks,
Robert

Robert A. Ober
IT Consultant, Vidcaster, & Freelance Preditor(Producer/Editor)
www.infohou.com
Houston, TX


Re: Resolution, was 8K Samsung TVs

Pawel Achtel, ACS
 

Bob Kartesz wrote: “…REC2020 color, for example, the current 4K color space, is woefully lacking in any sort of complete implementation for display and projection…”

 

I would add to this that I’m not aware of any camera that would accurately capture entire REC 2020 either.

Notably, I’m not aware of any 8K motion picture camera that would accurately capture even REC 709 highlighting there is much room for improvement when it comes to wide colour gamut and colour accuracy.

 

Having said that, 8K (and beyond) has its place and it is in Giant Screen productions, replacing 70mm film. For just about anything else, I agree, 4K seems to be perfectly adequate as delivery format.

 

Kind Regards,

 

Pawel Achtel ACS B.Eng.(Hons) M.Sc.

“Sharp to the Edge”

 

ACHTEL PTY LIMITED, ABN 52 134 895 417

Website: www.achtel.com

Mobile: 040 747 2747 (overseas: +61 4 0747 2747)

Mail: PO BOX 557, Rockdale, NSW 2216, Australia

Address: RA 913 Coles Bay Rd., Coles Bay, TAS 7215, Australia

Location: S 42° 0'14.40"S, E 148°14'47.13"

Email: Pawel.Achtel@...

Facebook: facebook.com/PawelAchtel

Twitter: twitter.com/PawelAchtel

Skype: Pawel.Achtel

 


Re: Resolution, was 8K Samsung TVs

Bob Kertesz
 

4K is dead get ready for 8K HDR which is a true 35mm frame.  Once we
are at 8K it’ll calm down a bit.
I suggest about 98% of U.S. consumers, cablecos, streaming services, and
satellite services would heartily disagree with you.

And about 75% (or more) of the production community. Including me.

What would be nice would be if we, as a whole, actually managed to get
4K right (or 'calmed down') before pushing for 8K, which is going to be
an incredible shit show for years.

REC2020 color, for example, the current 4K color space, is woefully
lacking in any sort of complete implementation for display and
projection. Yes, cameras can capture it all, but nothing can currently
show it all, and we're years into 4K. How likely will it be that 8K will
be any better, and how long is that going to take?

And I learned just last week that the only 4K channel being spewed (and
really, really badly) by DirecTV is not 4K at all; it is 1080p60 being
upscaled, compressed to DEATH, and then touted as 4K. How is that helpful?

I have yet to hear a DP say "Y'know, I'd love to shoot in 8K because
shooting at the current 6.5K just doesn't give the people who deal with
my footage in post nearly enough latitude to fuck up my framing."

-Bob

Bob Kertesz
BlueScreen LLC
Hollywood, California

Engineer, Video Controller, and Live Compositor Extraordinaire.

High quality images for more than four decades - whether you've wanted
them or not.©

* * * * * * * * * *


Re: Resolution, was 8K Samsung TVs

Video Assist Hungary
 

Just FYI. I’m watching the today-opened streaming service AppleTV+, in Central Europe, on cabled net. My 4K hdr Dolby vision stream is measured by my Mikrotik router at 14Mbps.

Balázs Rozgonyi
CEO video assist hungary


Re: Resolution, was 8K Samsung TVs

Bob Kertesz
 

I don’t think using an antenna will give you an uncompressed signal.
Not even close, unfortunately.

At best, it's 19.2 Mbits in the U.S.,and often significantly less since
broadcasters are allowed to put an HD and up to four SD 'side channels'
into the space.

If all four side channels are enabled by the broadcaster, the HD signal
can easily drop to below 15 Mbits. When you compare that to the
originating data rate at the camera, it is compressed to death.

And most cable companies and all satellite providers step on the signal
further, bringing the data rate down to 9 Mbits or even lower, which is
why if you're watching a football game and there's a wide shot with
players running down the field, it looks like they're being followed by
a swarm of bees. The compression artifacts are unbearable.

Having said that, a full 19.2 Mbits looks better than it has any right to.

-Bob

Bob Kertesz
BlueScreen LLC
Hollywood, California

Engineer, Video Controller, and Live Compositor Extraordinaire.

High quality images for more than four decades - whether you've wanted
them or not.©

* * * * * * * * * *


Re: Resolution, was 8K Samsung TVs

Video Assist Hungary
 

I don’t think using an antenna will give you an uncompressed signal. I’m not sure about ATSC but in Europe, DVB-T, DVB-S, DVB-C uses the same compression - from the top of my head, mostly Mpeg2 and some MPEG4.
I used to run a small satellite downlink point with my dad. His hobby was to hunt for feeds, and we have a 180cm Andrews dish with a Tandberg DVB-S receiver. That was before HD. Once we caught an uplink directly from an OB van from the Red Bull air race in Rio de Janeiro. It was SD, but it occupied the whole channel, so it was around 50 Mbit mpeg2 4:2:2 if I remember right. It was one of the best ever picture I’ve seen over the air (we had a broadcast Sony monitor and a Sony tv). It easily beaten most HD channels. Now we are cramming 4K in about the same bandwidth.

Balázs Rozgonyi
CEO video assist hungary


Re: Resolution, was 8K Samsung TVs

Jonny Revolt
 

4K is dead get ready for 8K HDR which is a true 35mm frame.  Once we are at 8K it’ll calm down a bit.

Be well,


Jonny Revolt
DIT
Local 600
Santa Monica/Atlanta
IMDB Linkedin
310-409-5795
jevolt888@...

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On Oct 22, 2019, 22:14 -0400, Ganzo <ganzo@...>, wrote:

I only watch broadcast signals using an antennae - no compression, best HD picture I can get on my Panasonic Plasma. As to the streamers, unfortunately my Roku doesn't have an ethernet in, only wireless, so I am captive to whatever Spectrum (TWC) can give me, and my TV is not near my modem so the download is close to pitiful. I think I need to move the modem!
R. Schaefer
New Orleans


Re: Resolution, was 8K Samsung TVs

Roberto Schaefer, ASC, AIC
 

I only watch broadcast signals using an antennae - no compression, best HD picture I can get on my Panasonic Plasma. As to the streamers, unfortunately my Roku doesn't have an ethernet in, only wireless, so I am captive to whatever Spectrum (TWC) can give me, and my TV is not near my modem so the download is close to pitiful. I think I need to move the modem!
R. Schaefer
New Orleans


Re: Resolution, was 8K Samsung TVs

daveblackham@...
 

I think its useful to define the dictionary or things may become confusing. By resolution, Im referring to the number of photo sites on the sensor so 4k would be 4096 8k 8192. Im not referring to resolved line pairs.

From a business perspective we haven't shot 4k for years all of it has been 5.5k or greater and for the last two years usually 8k acquisition. There has been some recent work with Red's Gemini camera to offer higher ISO which has been the only real reason not to shoot 8k. The other salient point is companies contractually request, Raw capture, 4k or greater resolution, and material shot for HDR delivery and that can be to Dolby's spec of 1000 or 4000 NITS. My own view is any camera entering the market now in resolution terms 4k might not be enough. We can argue all we want between ourselves but if the client insists this is the standard they wish to acquire then they are paying the bill and thats what should happen. In reality we have been working in 8k now in camera and post to output a 4k HDR deliverable and it seems to be working quite well.

Geoff's point is very relevant though it isn't all resolution it also has to be DR and colour too, they have to come hand in hand or we are wasting our time.

The other point is given the 6k and 8k camera systems deployed, glass hasn't been mentioned yet and thats critical in this discussion too.

For any one interested, Ive been asked to assist with the design of a 16k HDR cinema for research purposes, and it really has to deliver that on screen, so I think the resolution/HDR/colour game is far from over.

Dave Blackham
Esprit Film and Television
UK


Re: Resolution, was 8K Samsung TVs

RICHARD ROEPNACK
 

On the other hand, it’s heartening to know that they finally have compressors that go all the way up to 11.

Richard Roepnack

Man With A Movie Camera LLc

New York 



Richard Roepnack

Richard Roepnack Motion Pictures LLC

New York 917 655 5790

On Oct 21, 2019, at 2:04 PM, Bob Kertesz <bob@...> wrote:


But in terms of what's deployed focus is always on the mass market,
which typically means a television or box potentially only hooked up
via WiFi to deliver 4K streaming content from the usual suspects and
often w/ shared connections. Which is why the target really is sub-20Mbps.
What concerns me is that in the effort to deliver 4K and sooner or later
8K, we are going to have a years-long repeat of how badly HD was rolled
out by satellite and cable in the U.S., how utterly horrible and
compressed to death it was.

Which is to say, both cable companies and satellite companies will
undoubtedly do their best to squeeze 20 lbs. of shit into a 5 lb.
container with the same horrendous attitude of "We need to put this into
the same space as a currently highly compressed HD channel. So let's
turn the compressor up to '11'."

And of course the current mantra of "No one will notice anyway - for one
thing, they're watching on 7" screens."

It's not like that's not the exact history of how things have gone. And
if the 4K feed from DirecTV I saw just a few weeks ago is any
indication, it's going to suck hugely. Just jaw-droppingly awful
compressed to death trash.

Netflix and Amazon don't have to worry about putting more and more
channels that pay for carriage onto the service, nor do they have to
deal with launching satellites or building out physical infrastructure,
a very labor intensive endeavor. It's just simpler for satellite and
cable to compress the image harder, and it's what they are used to doing
for two decades now.

-Bob

Bob Kertesz
BlueScreen LLC
Hollywood, California

Engineer, Video Controller, and Live Compositor Extraordinaire.

High quality images for more than four decades - whether you've wanted
them or not.©

* * * * * * * * * *


Re: Resolution, was 8K Samsung TVs

Video Assist Hungary
 

That’s pretty crazy.
Hungary (Central-Europe) has about 90% 4G coverage. Sitting in my home I get about 15/15 up/down on my wired provider, and 50/50 on my phone.

Balazs Rozgonyi
CEO video assist hungary


Re: Resolution, was 8K Samsung TVs

Robert A. Ober
 

Philip Holland wrote on 10/21/19 1:26 AM:

It's frustrating in the US, but improving in areas that are obviously key markets.  Part of the difficulty is the size of the land itself and servicing about 300 million people spread out pretty massively.  As well as the expense and red tape that hinders quicker deployment of newer technologies.  That's a common theme out here.

Early gigabit and 5G were deployed in smaller lower risk markets, but that's finally expanding to places like Los Angeles.  California alone is about 40 million people. South Korea where much of my "tech forward work" comes from is about 50 mil.  As is England for that matter.

––––––––––––––––––––––––

I laugh at all the ruckus over 5G.  4G has never been properly rolled out to some of us.

I'm on the west side of Houston, TX.  Houston is the 4th largest US city in population, third largest in area. 

My neighborhood is middle class and was built in 1965.  Using Verizon 4G I'm lucky to get 3mb/sec inside or out.  I have called them several times.  Upload is around .6 mb/sec.  Fortunately I have a wired connection that is around 55 down and 11 up.  I usually have no problems with Netflix UHD (let's use the correct term, it is NOT 4K.) delivered via an Apple TV box to a Sony XBR.

My word to telecom providers would be, let's fix the current problems before promising another technology that you can't deliver.

Y'all take care,
Robert

Robert A. Ober
IT Consultant, Vidcaster, & Freelance Preditor(Producer/Editor)
www.infohou.com
Houston, TX


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