AV Chat

[Owen Smith]

Well, for the vast majority: no. There might be just a few people who can perceive some jerkiness in fast action at p25, but that pretty much disappears by using interlacing - you get a low-res image every 1/50s, which integrates over two frames to produce a full-res image.

Cinema (using film, not digital) is effectively progressive scan (the whole image changes each time), and is 24fps. Do you have a problem with jerky action at the movies? Do you think they would have standardised on 24fps if that wasn't fast enough??

24fps is not fast enough, viewers in cinema could see the flicker caused by the shutter on the projectors. The film advances to the next frame only when the shutter is closed to avoid blur, the shutter opens to project the image, the shutter closes again, and the film advances to the next frame. To avoid problems caused by 24fps flicker, the shutter opens and closes twice per film frame. So there are only 24 frames per second, but the flicker from the projector shutter opening and closing is at 48Hz.

This causes problems. In 2001 Kubrick found that if the camera panned too quickly across a starfield, the viewers saw each star split into two. So pans had to be kept below a certain speed to avoid this.

On CRT monitors on computers I needed about 100Hz refresh rate when I got a 19" monitor. Any less and I got headaches and eyestrain. Before that on 17" monitors I needed 70Hz, and on 14" high persistence green screen monitors 50Hz refresh was fine. The problem is based on persistence of the phosphor (which got shorter over time as gamers demanded faster and faster response times), angle subtended at the eye (so bigger monitors or sitting nearer saw more flicker) and refresh rate.

LCDs are completely different. They operate on a "sample and hold" basis. So even if refreshed at 10 frames per second there would be no flicker, only jerky motion. So the refresh rate on LCDs only determines how quickly any update is seen on screen. My CRT flicker problems have gone away completely with LCDs. I used to be constantly fiddling trying to get faster refresh rates to relieve my eyestrain. With LCD monitors on computers I just turn them on and use them with default settings.

 

[Deleted member 473]

I don't think there is any case to be made for interleaving now, is there?

I thought BH was talking of the filming rate, or the frame rate on the final version, not having to be over 24fps. You can always introduce extra frames in the cinema by means of a spinning shutter with 2 or 3 blades.

Far worse is the judder caused by converting 24fps to 25 or 30fps and vice versa.

I know it is complicated by people filming at 24fps in a country like ours where the mains lighting is driven at 50Hz.

 

[grahamlthompson]

24fps is not fast enough, viewers in cinema could see the flicker caused by the shutter on the projectors. The film advances to the next frame only when the shutter is closed to avoid blur, the shutter opens to project the image, the shutter closes again, and the film advances to the next frame. To avoid problems caused by 24fps flicker, the shutter opens and closes twice per film frame. So there are only 24 frames per second, but the flicker from the projector shutter opening and closing is at 48Hz.

This causes problems. In 2001 Kubrick found that if the camera panned too quickly across a starfield, the viewers saw each star split into two. So pans had to be kept below a certain speed to avoid this.

On CRT monitors on computers I needed about 100Hz refresh rate when I got a 19" monitor. Any less and I got headaches and eyestrain. Before that on 17" monitors I needed 70Hz, and on 14" high persistence green screen monitors 50Hz refresh was fine. The problem is based on persistence of the phosphor (which got shorter over time as gamers demanded faster and faster response times), angle subtended at the eye (so bigger monitors or sitting nearer saw more flicker) and refresh rate.

LCDs are completely different. They operate on a "sample and hold" basis. So even if refreshed at 10 frames per second there would be no flicker, only jerky motion. So the refresh rate on LCDs only determines how quickly any update is seen on screen. My CRT flicker problems have gone away completely with LCDs. I used to be constantly fiddling trying to get faster refresh rates to relieve my eyestrain. With LCD monitors on computers I just turn them on and use them with default settings.

Strange that blueray only supports 1080p at 24 fps. To get 50 you need to reduce the resolution to 720p (1280 x 720). You do of course need a TV that can actually synch at 24Hz, Your post indicates the strong possibility that yours cannot do so,

Not noticed anyone unhappy with bluray playback with a suitable TV.

Basically you need a display that can display one frame for every frame at the exact framerate of the source.


A good example is a plex client on a 4K firestick.

Explanation of the new Frame Rate Matching feature on the Amazon Fire TV and how it works

Software update version 6.2.5.3 to the Amazon Fire TV has added the ability to configure the media player so that it adjusts your TVs refresh rate to match the frame rate of the video content being played.

www.aftvnews.com

 

[Owen Smith]

Strange that blueray only supports 1080p at 24 fps. To get 50 you need to reduce the resolution to 720p (1280 x 720). You do of course need a TV that can actually synch at 24Hz, Your post indicates the strong possibility that yours cannot do so,

My TV can do 1080p 24fps, and does so when playing blu rays with my Oppo 95 player. It looks fine to me.

When discussing CRTs and high refresh rates that was at work with my computer monitor. But it is a demonstration of flicker issues, and that LCD with its "sample and hold" behaviour is completely. It still has frame rate issues with motion smoothness, but the flicker from phosphor persistence is completely gone with LCD.

 

[Black Hole]

Flicker is not the same as the refresh rate required for smooth motion. Some people are more sensitive to flicker than others. Modern TV displays do not flicker.

 

[Owen Smith]

Flicker is not the same as the refresh rate required for smooth motion. Some people are more sensitive to flicker than others. Modern TV displays do not flicker.

Which is almost exactly what I said. But you insist on having the last word as ever.

 

[Deleted member 473]

playing blu rays with my Oppo 95 player.

Wow, what extra features do you get from a bdp that retailed at £900?

 

[Black Hole]

Which is almost exactly what I said. But you insist on having the last word as ever.

Sorry, I didn't realise people are banned from making their own independent comments.

 

[Owen Smith]

Wow, what extra features do you get from a bdp that retailed at £900?

Zero features compared to the Oppo 93, the digital sections are identical. What I get is high quality 7.1 multi channel analogue outputs from a separate audio board using two ESS Sabre DACs, which I feed into my older AV amp which doesn't support HDMI audio. I've done a comparison with the Oppo 93 and I can hear the difference.

 

[sine24]

For 900 squids you could have bought 3 hdmi amplifiers. And get some change for a 4k B-ray

 

[trog]

And you get 3 mopeds and change for a bicycle instead of buying a Harley

 

[Owen Smith]

I don't want to part with my Arcam AVR350 AV amp, and even if I did I sincerely doubt a £300 AV amp would match it for sound quality. I'd have to spend considerably more than that to replace it. And besides, I'm tight for space and newer AV amps have got taller and won't fit where the AVR350 does.

 

[Deleted member 473]

I don't want to part with my Arcam AVR350 AV amp, and even if I did I sincerely doubt a £300 AV amp would match it for sound quality. I'd have to spend considerably more than that to replace it. And besides, I'm tight for space and newer AV amps have got taller and won't fit where the AVR350 does.

?

 

[Owen Smith]

?

Connected to the previous posts about £900 buying three HDMI amps and a bicycle with the spare change.

 

[Black Hole]

Wow, what extra features do you get from a bdp that retailed at £900?

I've done a comparison with the Oppo 93 and I can hear the difference.

Frankly, I'm with OS here. I doubt I would be able to hear a difference, or care very much even if I could, but if that's what floats his boat - why not? I might raise my eyebrows a bit if large amounts were being spent on always having the latest and greatest on a six-month cycle, but again that's none of my business, and if he can afford it why not?

It's not like I spend a lot less on my own pursuits (in normal times, probably a lot more), and have you seen the price of a football season ticket, or golf club membership (not that I do either of those)?

 

[Deleted member 473]

Connected to the previous posts about £900 buying three HDMI amps and a bicycle with the spare change.

Sorry, still can't find it.

 

[Deleted member 473]

Frankly, I'm with OS here.

I am with Owen too. I was merely checking what you got for that money. Of 3 bd players I have, 2 were free and one was part of a hdd recorder. His clearly has extra features on top of just decoding a digital recording and passing it on to the amp. Which is all mine do.

 

[Black Hole]

just decoding a digital recording and passing it on to the amp. Which is all mine do.

Mine don't even do that. I suspect OS wouldn't want to take up residence here!

Sorry, still can't find it.

And you get 3 mopeds and change for a bicycle instead of buying a Harley

 

[Deleted member 473]

Ah, on ignore!

 

[Deleted member 473]

Mine don't even do that. I suspect OS wouldn't want to take up residence here!

I have great respect for those who take audio seriously. I can't persuade my scratlets to accept old speakers rather than use the TV ones or a soundbar. It transforms viewing. What a shame terrestrial uses 2.0 DD on HD rather than even 5.1.

Is anything on terrestrial broadcast in 5.1?