1080p/24 vs. 1080p/60

Serendipity

On my HTPC I have the option to choose from 1080p/24Hz or 1080p/60Hz in the display properties menu.

The HTPC is connected to a Epson 1080UB projector, which can sync at both 1080p/24 and 1080p/60.

I am currently using the 1080p/24 output on the HTPC, but would I see a difference in going to 1080p/60? Would this be better or worse?

cheddar

24hz is a HT mode. Movies have a native 24 frame per second cadence and this lends a 'theater' feel to movies rather than a 'video' feel to them. So these movies are ideally seen in either 24hz or a multiple of 24hz to prevent 3:2 pulldown frame copies and introduction of judder.

For non-HT material such as HDTV, 60hz and higher can make for smoother motion especially on fast moving material like sports. However, people have varying sensitivities to motion judder and such and YMMV.

ND13

I've been looking at the Sharps that are 120hz. They have a side by side demo mode that shows the difference between 120 and 24.

JohnLocke88

ND13 wrote: »

I've been looking at the Sharps that are 120hz. They have a side by side demo mode that shows the difference between 120 and 24.

And?

Generally speaking, I use 60Hz on my Samsung when I'm gaming, and 24Hz for movies and such, for reasons stated in the first response post.

vague_notion

Sorry to bring this thread back but I thought it would be good to answer the question in case anyone else stumbles on it.

120Hz is useful because it divides evenly by both 24Hz and 60Hz. So you don't have to switch modes when switching between 24 frame and 60 frame content. Both look normal when displayed at 120Hz.

24 frame/sec content shows each frame 5 times. (24*5=120)
60 frame/sec content shows each frame twice. (60*2=120)

I hope this helps someone.

Conradicles

On my Pioneer Plasma TV I can choose 24, 60, or 72 frames per second. I like them all. The 1080/24 looks most like a true motion picture, but my eyes are most used to 60 fps as that is what most of us have watched our whole lives.

Basically, I am still experimenting and trying to find which one I like the best. Sorry that this post is useless lol.

Squishy Tia

vague_notion wrote: »

Sorry to bring this thread back but I thought it would be good to answer the question in case anyone else stumbles on it.

120Hz is useful because it divides evenly by both 24Hz and 60Hz. So you don't have to switch modes when switching between 24 frame and 60 frame content. Both look normal when displayed at 120Hz.

24 frame/sec content shows each frame 5 times. (24*5=120)
60 frame/sec content shows each frame twice. (60*2=120)

I hope this helps someone.

The 120 Hz modes also introduce about 100ms of input lag. You'll need to adjust your AVR's audio delay to match that. Also, 24 FPS material benefits greatly from 120 Hz modes, but 60 FPS material does not. In fact, 60 FPS material, especially poorly encoded (MPEG) material on both blu-ray and DVD/TV at 60 FPS will have a lot of stutter and dropped frames using a 120 Hz mode hither than the basic (Clear on Samsung TVs) setting.

If you are using PC Mode in addition to a 120 Hz mode, you'll also have an extra 20ms of input lag. Adjust accordingly.

Samsung AMP (AutoMotionPlus 120/240 Hz) modes:

Clear: Use for DVDs. Anything higher and you get stutter. Elmer Fudd stutter or worse. Minimal "soap opera" camera effect. Still shows some of the flicker (pixel transition delays) inherent to non-smoothed video.

Standard: Great for TV and sports. Works excellently on 24 FPS material (Blu-Ray) as well. Has moderate "soap opera" camera effect.

Smooth: Works pretty well for BDs, with the exception being some poorly encoded MPEG-4 video on older Blu-Rays. Most AVC and VC-1 encodes are of high enough quality that you get little to no stutter/frame drops. Has the most significant "soap opera" effect.

NOTE: LED Motion Plus on Samsung LED TVs is a feature that uses LED strobing every 1/60th of a second (the equivalant of adding a single v-blank to each frame). It dims the picture and (theoretically) helps with fast moving scenes to make them appear less incongruent (i.e. as if they don't have flicker). Sadly this mode itself induces flicker due to the LED strobing. If you get headaches from watching video on CRTs due to flicker, don't use this mode.

mystik610

Conradicles wrote: »

On my Pioneer Plasma TV I can choose 24, 60, or 72 frames per second. I like them all. The 1080/24 looks most like a true motion picture, but my eyes are most used to 60 fps as that is what most of us have watched our whole lives.

Basically, I am still experimenting and trying to find which one I like the best. Sorry that this post is useless lol.

A lot of people don't like Blu-ray because it looks 'fake', or 'looks like home video'. We really have gotten used to the juddering that occurs when film (shot at 24fps) is displayed on a screen that refreshes at 60hz. It seems we've associated the juddering itself as the sole characteristic that make movies look like movies.

On the flip-side, video looks like video because it isn't subject to any juddering. Most film is shot in 30 or 60fps, and displays evenly on a 60hz display.

When a blu-ray movie is displayed at 24fps on a 72, 120, or 240hz screen, it eliminates any juddering. The transition between frames is perfectly smooth, causing it to look like video. It might look odd to some, that is how movies are intended to look.

Long-story short. Use the 72hz mode!

Squishy Tia wrote: »

The 120 Hz modes also introduce about 100ms of input lag. You'll need to adjust your AVR's audio delay to match that. Also, 24 FPS material benefits greatly from 120 Hz modes, but 60 FPS material does not. In fact, 60 FPS material, especially poorly encoded (MPEG) material on both blu-ray and DVD/TV at 60 FPS will have a lot of stutter and dropped frames using a 120 Hz mode hither than the basic (Clear on Samsung TVs) setting.

If you are using PC Mode in addition to a 120 Hz mode, you'll also have an extra 20ms of input lag. Adjust accordingly.

Samsung AMP (AutoMotionPlus 120/240 Hz) modes:

Clear: Use for DVDs. Anything higher and you get stutter. Elmer Fudd stutter or worse. Minimal "soap opera" camera effect. Still shows some of the flicker (pixel transition delays) inherent to non-smoothed video.

Standard: Great for TV and sports. Works excellently on 24 FPS material (Blu-Ray) as well. Has moderate "soap opera" camera effect.

Smooth: Works pretty well for BDs, with the exception being some poorly encoded MPEG-4 video on older Blu-Rays. Most AVC and VC-1 encodes are of high enough quality that you get little to no stutter/frame drops. Has the most significant "soap opera" effect.

NOTE: LED Motion Plus on Samsung LED TVs is a feature that uses LED strobing every 1/60th of a second (the equivalant of adding a single v-blank to each frame). It dims the picture and (theoretically) helps with fast moving scenes to make them appear less incongruent (i.e. as if they don't have flicker). Sadly this mode itself induces flicker due to the LED strobing. If you get headaches from watching video on CRTs due to flicker, don't use this mode.

It should be noted that the automotion plus/motionflow/etc etc modes do not disable the 120hz refresh rate. They are not '120hz modes'. Those are frame interpolation modes that are essentially rendering 'transitional frames' between actual frames to smooth out the picture.

You can still benefit from a 120hz refresh rate, 5:5 pull-down, and smoother 24p content with these modes off.

Squishy Tia

Long-story short. Use the 72hz mode!

That'd be great, if the displays supported it. They don't. They max out at 60 Hz. And on that note...

It should be noted that the automotion plus/motionflow/etc etc modes do not disable the 120hz refresh rate. They are not '120hz modes'. Those are frame interpolation modes that are essentially rendering 'transitional frames' between actual frames to smooth out the picture.

You can still benefit from a 120hz refresh rate, 5:5 pull-down, and smoother 24p content with these modes off.

Erm. I hate to break this to ya, but these TVs are not 120 Hz displays. Again, like all computer monitors, they top out at 60 Hz refresh. They do not accept any signal faster than 60 Hz, the internal electronics do the frame transitions and conversion/interpolation, then either inject the frames in between the two key frames (24p/30/60fi), or in the case of true 60 FPS (Hz) video sources, will provide smooth effects, with the catch-22 of having problems with frame sync/stuttering.

The reason for the stutter with AMP and its brethren when used on 60 Hz sources is that unlike 24p (2.5:1), 30p (2:1), and 60 Fi [fields per second - interlaced video] (2:1), 60p/60 Hz is 1:1. What are the ratios? Dead time to actual frames. 24p is 2.5:1 becaues the display is 60 Hz, and 60 ÷ 24 = 2.5. This should help you understand the ratios.

Now the tricky part is the 1:1 ratio, 60p/60 Hz. AMP/MotionFlow, etc still interpolate frame data from 60 Hz material, but there is a hitch: where does that frame get injected when there is a 1:1 ratio between the video source and the display output? The answer? Some of the secondary key frames (the key frame that would normally come after the injected frame from the interpolator) is simply gone. And what this leads to is the "hurry up and wait" situation where AMP/MF/etc. create smoothed, but accelerated looking video (soap opera effect to the max), but reach a certain point where the frame injection timing becomes out of sync and then frames are actually dropped and you get the stutter until the AMP/MF processor re-sync with the video source's frames. Remember that 1:1 ratio? That means there is zero time for the processor to do its work, so it does the work and simply replaces the secondary key frames until it becomes out of sync and just stops. The stop usually lasts about 0.5 seconds - 1 second at the worst.

So why aren't these 120 Hz displays? Two reasons.

1) The back end does not support anything greater than 60 Hz. This can be technically changed should manufacturers have a reason to do so, but currently the only things capable of outputting a 120 Hz DVI/HDMI signal would be PC video cards. No consumer equipement can do so. Yet. It's a bandwidth issue as it requires just under 17 Gbps, which is a far cry more than the 10.2 Gbps maximum throughput of HDMI right now. Give it a couple years and this may change (at least I hope it does).

2) The LCD panels themselves are also limited to 60 Hz. The absolute fastest true response time of any LCD panel on the market is 16.67ms, which is 1/60th of a second (60 Hz). Manufacturers claim 2, 3, and 5ms times, but those are typically grey-to-grey, and not full color rotation transitions. And the GtG transitions vary by panel type and manufacturer. The internal electronics of today's TVs can simulate 120 Hz, but do not actually output it. That's why it's a "feaux 120 Hz" mode.

When the TV is at 24p, it isn't updating the display at 60 Hz. It's only updating the display at 24 FPS. This is why Blu-Ray looks flickery. Film has the same flicker, and you'll easily see it in theaters. If your TV is not flickering somewhat at its stated 24p resolution, then it is not in fact true 24p. The reason TVs drop to 24 Hz (true 24 Hz) is a) to provide exact filmlike video as created from the original source material, and b) to avoid 3:2 pulldown which would occur if the TV operated at 60 Hz output, but 24 Hz internally.

So no, these are not 120 Hz displays. They're 60 Hz displays with electronics that mimic 120 Hz through interpolation and frame injection. A true 120 Hz display would appear smooth (very much so), but without the soap opera effect that AMP/MF cause when in use at anything higher than their basic settings. True "soap opera" video actually has no "accelerated" video feel. It's just smooth with no speed variations. AMP/MF have speed variations, though minor, due to sync issues involved in processing time, getting progressively worse and more stutterific the closer you get to 60 Hz source as opposed to 24 Hz source video.

Once again: There are no 120 Hz displays on the market. They would require a minimum response time of 8.33ms, something current LCD technology outside development prototypes (maybe) can do.

kuntasensei

So if there are no 120Hz displays on the market, how do you explain this?
http://global.epson.com/newsroom/2008/news_20080909.htm

Or were you specifically referring to flat panel displays and not projectors?

Squishy Tia

kuntasensei wrote: »

So if there are no 120Hz displays on the market, how do you explain this?
http://global.epson.com/newsroom/2008/news_20080909.htm

Or were you specifically referring to flat panel displays and not projectors?

These units are panels for projectors, but that part is actually moot since they are LCD technology. The part that is not moot is that these are specially overdriven (by electronics) units that are 0.7 inches in diagonal measurement. To even compare them to full size 22" and larger computer monitors and TVs isn't even remotely realistic.

It's going to be at least a couple years before we see even smaller size LCD panels display a true 120 Hz refresh, and another two or three years after that likely before they're cheap enough to be "mass market" ready outside large corporations' swiss bank funds.

So yes, there are still no LCD panels of realistic size for consumer use on the market. That's like saying that OLED TVs are "on the market for consumer use" when they're clearly still exotic tech and puny, almost worthless sizes.

It'll be interesting to see which actually becomes consumer friendly (in both usability and wallet hit) first, quite honestly. Keep in mind that at 0.7 in. diagonal, the pixels are 8.5 micrometers in size. Market level LCD panels are measured in millimeters in comparison. That's a HUGE difference in physical area that must be manipulated by an electrical current/IC driver.

Don't get me wrong, I'm glad Epson's got something going. But we're talking effective prototype that is barely ready for production. And it's in Japan only (note its tech is D7, the successor to D5, Japan's SD/HD connection format)

If a consumer can't buy this without taking out a second mortgage, I'd say it's fair to assume this isn't "on the market" outside the most upper echelon of moneygrubbers.

kuntasensei

Uh... Double Speed D7 panels aren't prototypes. They have been IN projectors since last year. My Epson 8500UB is 120Hz at the LCD panel. For 60fps sources, it doubles or frame interpolates to 120Hz... for 24fps, it runs at 96Hz with 4:4 or you can FI to 120Hz. No one would have to take a second mortgage for that... You can get a projector with D7 panels at 120Hz for less than $2k.

I understand what you mean about them not necessarily being 120Hz displays, since I doubt even my projector would accept 120Hz from a video card and do 1:1 display of it. But to say that LCD panels are limited to 60Hz seems erroneous to me. Viewsonic has had 120Hz displays out since 2008 that will accept 120Hz signals... and also do 60Hz stereoscopic with shutter glasses. Plus, how do you reconcile what you're saying with the newer 240Hz LCD displays with 2ms GTG? That's not "faux 240Hz" - the panel actually has to display at that rate. Sure, there's no content that runs at 240Hz, making it unnecessary other than to reduce panel-induced motion blur or to use MEMC... but the panel itself does actually refresh at that rate.

I guess I'm just confused by what you're trying to say.

Squishy Tia

I understand what you mean about them not necessarily being 120Hz displays, since I doubt even my projector would accept 120Hz from a video card and do 1:1 display of it.

Assuming the video card can indeed produce the 120 Hz signal (as in it has the bandwidth to do so on the LDVS/TMDS channels), and there is no preprocessing going on, the unit you have should be able to accept a pure 120 Hz signal at 1:1 with no issues (this also assumes your unit accepts 120 Hz signals and the 17Gbps worth of bandwidth necessary for such a signal).

But to say that LCD panels are limited to 60Hz seems erroneous to me. Viewsonic has had 120Hz displays out since 2008 that will accept 120Hz signals

Are you referring to say, this Viewsonic monitor? If so, it's using some pretty obvious tactics to reach anything near 120 Hz. Let's go through them, shall we?

1) Its resolution is 1680x1050. Not even full HD. Yet it requires a Dual Link DVI cable to run at 120 Hz. This is the bandwidth issues I've mentioned before. It's using what would normally go to increased resolution to instead go toward increased bandwidth. Single link HDMI/DVI has a current top throughput of 10.2 Gbps. This monitor looks to be running at about 14 Gbps, hence the need for dual link DVI for such a low resolution.

2) It's a TN Panel. TNs are fast. Very fast. Gamers prefer them for their low response time. Problem is, there are almost no true 8-bit TN panels. It may have crisp imagery, but that's something TNs are known for anyway.

3) Response time listings of "GtG" are worthless. Those are simple response curves from one level of grey to the next within the panel's available native colorspace. What we're looking for is partially given by Viewsonic in its measurements. They give Black to White typical response (avg) of 5ms. But what's most important is a full rotation - BtWtB or WtBtW. Ideally you take both of those measurements (which can be very different) and average them to get the real response curve you should expect. In this case, assuming that the 5ms BtW response time is identical going back as WtB, you get 10ms, 1.66ms slower than the 8.33ms minimum response time for a true 120 Hz. This explains why CNET had ghosting apparent on such a fast display, and a TN panel at that (TN panels are typically known for NOT ghosting, while PVA/IPS are due to increased response time/lag).

4) Trickery. Remember that nvidia stereoscopic 3D gaming kit? The shutter glasses tech? Now remember that 60 Hz stereoscopic 3D you mentioned? The reason it can do so is that the monitor is utilizing dual link DVI to supply two independent single link 60 Hz signals. The shutter glasses themselves have nothing to do with 120 Hz, as they are external. The reason CNET can't get movies to play back at all in 120 Hz, is because the monitor is using the trickery of two single link DVI connections simultaneously to achieve 120 Hz, and not one component in the consumer market can even send a signal that's compatible with being interleaved like that yet.

This monitor is more of a hack than a truism, but it's a very nifty approach to it. TN panels like this will likely be the first (and cheapest) solution for 120 Hz, while it will take some time longer to get PVA and especially the lagtastic IPS panels up to this speed.

One more thing on this monitor - remember I called it trickery in #4? You aren't getting a true 120 Hz signal via DVI. DVI tops out at 75 Hz, with 60 Hz being the most common. The monitor uses two 60 Hz signals to create a 120 Hz signal, but is not receiving a 120 Hz signal (it's a thin line they're crossing there in terms of marketing claims). It's a grand effort, but it isn't true 120 Hz.

... and also do 60Hz stereoscopic with shutter glasses.

Shutter glasses have nothing to do with 120 Hz. They're external and separate to the LCD panel itself.

Plus, how do you reconcile what you're saying with the newer 240Hz LCD displays with 2ms GTG? That's not "faux 240Hz" - the panel actually has to display at that rate. Sure, there's no content that runs at 240Hz, making it unnecessary other than to reduce panel-induced motion blur or to use MEMC... but the panel itself does actually refresh at that rate.

Again, GtG is worthless for the reason I stated above. 240 Hz displays must be capable of a full color rotation in 4.16ms or less. These displays are not. The internal electronics can simulate 240 Hz via frame interpolation, creating very smooth video, but it is not 240 Hz video. It's yet another marketing gimmick, same as the AMP 120 Hz mode in my Samsung TV is. AMP can interpolate frames and inject them to smooth out video making it appear as if the display is truly outputting at 120 Hz, but the panel is still outputting at 60 Hz. It's very clever frame manipulation that gives the effect of increased refresh rate. But the bandwidth just is not there for it. True 240 Hz displays would require twice the bandwidth of a true 120 Hz display, and four times the bandwidth (and TMDS clock) of a 60 Hz display. And at 1920x1080, that's 34 Gbps. The TV might be able to handle that internally, but the display and back and certainly cannot. That's like HDMI 1.4 having the claim of 4k x 2k video. Except that in order to achieve that high a resolution using HDMI/DVI, the refresh rate is cut in half compared to 1920x1080 (the 4k x 2k resolution is actually 3840x2160).

And that is why these are all tricks. Bandwidth doesn't come magically out of nowhere. Video cards most certainly can achieve the bandwidth needed, but the displays themselves cannot yet, at least not in all three of the parts of a display (back end/inputs, processor, and output panel). When all three are capable of 120 Hz without tricks, then it's true 120 Hz.

Serendipity

kuntasensei wrote: »

Uh... Double Speed D7 panels aren't prototypes. They have been IN projectors since last year. My Epson 8500UB is 120Hz at the LCD panel. For 60fps sources, it doubles or frame interpolates to 120Hz... for 24fps, it runs at 96Hz with 4:4 or you can FI to 120Hz. No one would have to take a second mortgage for that... You can get a projector with D7 panels at 120Hz for less than $2k.

Looking at a new projector...

Would the new panels in the Epson 8700UB be a significant upgrade?

I'm currently running the Home Cinema 1080UB.

mrbigbluelight

You know what ? A person can really learn some stuff at this place.

TouchOfEvil

Sounds like some good information but dang my head hurts now lol.

dragon1952

mrbigbluelight wrote: »

You know what ? A person can really learn some stuff at this place.

If you can comprehend what's being explained :frown:

Tony M

Thank you for bringing this back up.

Older guys like me need a refresher explanation every so often. Keep em coming and maybe I'll be able to get THE Most that my components have to offer. I fell like I could use 5 - 8hr days with somebody like my old friend Chris "my menu man" who I think understands this compex problems when we marry one Tv to another brand AVR. with over 100 pages of instuctions to read, I get frusrtated real fast and mosely walk away and come back again somemetime in a week or so..LOL.

Chris was my savior 6months ago or longer and did what he thought should be done. I'm happy with all of it but I want to understand the formats choices I can have. It's got to be simple if I start early in the morning and absorb this newfangled techs knowledge and limits or cons.

Just like me wanting to learn crossovers before a year passes.

But anybody that needs help on mateting this blu-ray to huge thin flatscreens should ask and that will educate somemore of us who happen to be slow minded with all this tech coming at us more than we can remember.

Thanks

DON73

Old guys like me just need a couple Advil.
When the experts disagree as some have in this post I lose interest because I don't know which bit of information is accurate.
I'm going on over to the Vintage Speaker forum where all Vintage members (over 70) belong.

inspiredsports

post #20 by promobank6 reported as spam for removal

Tony M

DON73 wrote: »

Old guys like me just need a couple Advil.
When the experts disagree as some have in this post I lose interest because I don't know which bit of information is accurate.
I'm going on over to the Vintage Speaker forum where all Vintage members (over 70) belong.

I'm afraid technology is leaving us behind no matter how hard we try to keep up....:redface::biggrin: