Best framerate conversion? (eg: 23.97 to 30 fps to avoid judder)

[ionone]

I want to get rid of the judder when i watch DVDs, so i decided to convert my video collection to 30 fps (i have a 60hz refresh rate screen)

What is the best motion compensated conversion out there ?

i'm aware of : Fizick, Depan, MVtools, MotionPerfect, but what is the best visual quality ?

let's make a clear summary on all what exists and what is best...

thanks for help

regards,

[guns1inger]

There is no good way to do this other than to let your TV do the work for you. If it is that bad then your TV isn't doing what is supposed to, or isn't capable of doing it, but forcing a telecine to 29.970 (which at least has precedent, and which your DVD player is probably doing for you anyway), or worse, 30 fps is only going to give you inferior image quality.

[edDV]

Judder is alway present on a 59.94 fps display unless you reinterpolate every frame to 59.94Hz which would be highly lossy. The solution is a 5 x 23.976 = 119.88 fps display which does not require frame rate interpolation.

Since you are in France, normal European technique is to speed 23.976 ~4% to 25.0 fps for 2 x 25 = 50Hz or 4 x 25 = 100Hz display.

[jagabo]

Motion interpolation from 24 fps to 30 fps will get rid of the judder but 30 fps is still a bit jerky. The artifacts introduced by the motion interpolation may be worse than the judder. Motion interpolation to 60 fps will look very smooth but playback can be a problem. And there's still the issue of artifacts.

[BozQ]

ionone

What is your source? If your DVDs are confirmed to be 23.976 and you're playing on a 60Hz TV, then it's normal.
Converting 23.976 to 29.97 is a big no no, and it will result in a much more terrible video quality, wasting a lot of time in the process.

[jagabo]

Converting 23.976 to 29.97 is a big no no, and it will result in a much more terrible video quality

What exactly do you mean by that?

[Cornucopia]

This sounds like a spinoff of that other thread where the guy in ??Brazil?? had an LCD tv that "showed up too much of the slow fps", and then wanted the industry to change to fit his wishes...

Bottom line: You are trying to fit a square peg in a round hole. You're either going to have to...
A. Chop off the corners of the peg (bad)
B. Make new corners for the hole (bad)
C. Shrink the peg/Enlarge the hole so it slips in (bad)
Guess what they're all bad--you just have to pick one (or do nothing and one will already be picked for you)

It doesn't matter so much WHEN you do it (at which point in the steps), but your conversion will need to take place, and you will suffer a little quality from it. My guess is that the stock good progressive player with TC/IVTC control, or the stock conversion in a high-quality TV is gonna be nearly as good as you can get. PLUS, it's in real-time! All those other methods you're thinking of will cost you HOURS. And for how much better? (or "less worse")

Scott

[BozQ]

Converting 23.976 to 29.97 is a big no no, and it will result in a much more terrible video quality

What exactly do you mean by that?

It's unneccessary, as any DVD player will apply pulldown on 23.976 video to correctly display on 60Hz NTSC TV.
Converting the video would usually mean another level of compression done on the video. And if not done correctly, it would go as bad as the Ip Man video clip I recently I uploaded. I'm not sure if you remmebered me posting that.

I suspect something else is wrong somewhere that the original poster may not be aware that made him post for help here. Normally the pulldown performed by DVD players are not that distracting.

[jagabo]

It's unneccessary, as any DVD player will apply pulldown on 23.976 video to correctly display on 60Hz NTSC TV.

But that is exactly the cause of the judder the OP is referring too. Half the frames are displayed for two 60 Hz fields/frames and half are displayed for three 60 Hz fields/frames, alternating between the two. This disparity shows up as judder, especially noticeable on bright panning shots. If you are running a 60 Hz monitor watch this 60 Hz video enlarged to full screen:

24v30v60.avi

The top row is 24 fps with a 3:2 repeat pattern, exactly what you will see on a 60 Hz HDTV. The middle row is 30 fps with a 2:2 repeat pattern. The bottom row is true 60 fps. This sample is pretty much a worst case scenario. Most movies won't be this bad but the problem is noticeable in many shots.

Note that the 30 and 60 fps sections in the above example weren't created from the 24 Hz sample. All three rows were created from a 120 Hz original with decimation to produce the right frames.

Converting the video would usually mean another level of compression done on the video.

No doubt about that. But a good reencode doesn't have to look too bad.

I suspect something else is wrong somewhere that the original poster may not be aware that made him post for help here. Normally the pulldown performed by DVD players are not that distracting.

Given the tools the OP mentioned I think he does know what he's talking about. All those tools synthesize in-between frames by analyzing motion in the existing frames and figuring out what the in-between frames would have looked like. The question is whether the tools work well enough to be worth the time and effort. The new 100/120/200/240 Hz TVs can do this in real time with film sources.

This post:

https://forum.videohelp.com/threads/307004-Best-framerate-conversion-%28eg-23-97-to-30-...=1#post1888926

contains a short clip where the 60 fps motion compensation (MvTools) worked pretty well. (You can find the original 24 fps HD clip earlier in that thread.) Here's one where it worked very badly:

bad60.avi

All those grid lines are supposed to be straight.

[ionone]

So tu sum up, there is no way to get rid of the judder (with high quality as possible) using conversion ?

Only reclocking can remove judder ?

[jagabo]

I'm not sure what you mean by reclocking. The newer 120 Hz TVs can eliminate judder buy displaying each film frame for the same amount of time, 5/120 second each (60 Hz TVs alternate between 2/60 and 3/60 of a second). That leaves you with the inherent jerkiness of 24 fps film. Which they can smooth out with frames synthesized via motion analysis.

[ionone]

I'm not sure what you mean by reclocking. The newer 120 Hz TVs can eliminate judder buy displaying each film frame for the same amount of time, 5/120 second each (60 Hz TVs alternate between 2/60 and 3/60 of a second). That leaves you with the inherent jerkiness of 24 fps film. Which they can smooth out with frames synthesized via motion analysis.

reclock is a little directshow plugin (an audio driver actually) that simply plays the video faster or slower to remove judder

example : on a 75hz monitor, 23.976fps videos plays with judder. Reclock simply plays the video and audio faster to achieve 25fps to be in sync with the refresh speed.

http://reclock.free.fr/

but with a 60 hz screen on my laptop (which is stupidly locked at 60hz whereas the LCD could produce virtually any refresh rate) i can't play 23.976 video at 30fps (too fast) or 20 fps (too slow!) so reclock is useless for 60 hz screen rates.

of course a 120hz TV solves everything, but i was trying to find a solution for 60 hz screens

[Cornucopia]

OK, now I see what's going on...

This is simply a plug for this DS filter. SPAM, plain and simple. Look at the readme, it reads just like the OP's posts (either it's him or he's believed the developer whole hog and is quoting).

Plus, who'd want to use VIDEO as the clock source? You're doing a major disservice to the audio this way. Ever hear of "wow & flutter". It's an old analog term referring to variations in playback speed/pitch, and the pont was to have as little as possible (zero if you could get it). Major slow variations were "wow", minor fast variations were "flutter". So this developer (and the OP, if they ARE one and the same or of like mind) wants to bring back analog flutter just so he can get what he thinks is a better picture. There are better ways to do this, but they require locking the video source to a central clock throughout the chain. This is what's known as "GENLOCK", and the best studios do this, but it's expensive. And most of those central clocks are based around an AUDIO high MHz superclock generator. Get a look at the ones Digidesign makes, or Alesis. The point of those devices is HIGH PRECISION, LITTLE DRIFT.

But that's probably not the problem with most systems, since there's really more of a need for this when there are MULTIPLE sources needing to be synced together. Most playback is only 1 source to 1 output (although, obviously Audio+Video). The fault with the developer's inference is that the display device's timing is gospel. It isn't. It may be teling the system it's displaying/refreshing at one rate, but actually be refreshing at another rate. Even more likely, it probably DRIFTS, as it's going by it's own clock which is not built to the highest precision. That's another reason why studios use display devices that are built with connectivity to an external source to genlock with.

Face it. You've got a Consumer problem here, because of Consumer-level equipment. The only real solution is to get Pro-level equipment, not throw a Consumer-level workaround at it.

Scott

[ionone]

Interesting post but let's stay focused please.

i'm trying to find a way to avoid judder with 23.976 fps movies on a 60hz refresh rate LCD, either live or with conversion.

tell us if you have an idea

[jagabo]

Plus, who'd want to use VIDEO as the clock source? You're doing a major disservice to the audio this way. Ever hear of "wow & flutter". It's an old analog term referring to variations in playback speed/pitch, and the pont was to have as little as possible (zero if you could get it). Major slow variations were "wow", minor fast variations were "flutter". So this developer (and the OP, if they ARE one and the same or of like mind) wants to bring back analog flutter just so he can get what he thinks is a better picture.

No. The audio sample rate is simply increased or decreased to match the new frame rate. For example, to play a 23.976 fps video at 25 fps to get 3x frame repeats on a 75 Hz display, the sound card would be told that a 48,000 Hz audio source is 50,050 Hz (48000 * 25 / 23.976). You will simply get a slight pitch increase and shorter audio and video. I guess you could call this in infinite period wow but it's pretty much the same thing that is done on most PAL DVD releases (obviously, the resample the audio rather than change the playback rate).

There are better ways to do this, but they require locking the video source to a central clock throughout the chain. This is what's known as "GENLOCK", and the best studios do this, but it's expensive. And most of those central clocks are based around an AUDIO high MHz superclock generator. Get a look at the ones Digidesign makes, or Alesis. The point of those devices is HIGH PRECISION, LITTLE DRIFT.

A genlock would be totally useless for eliminating judder from frame rate mismatches.

[Cornucopia]

Yeah, jagabo, after mulling over what I wrote, I gathered that it had more to do with ITVC and FRC than the red herring that was brought up with reclock. (I understood the futility of using a genlock in that situation, which is why I wrote the bit at the end)

Anyway, I have tech suggestions for the OP but I can tell he's not gonna like 'em, so I'll just quit for now.

Scott

[pandy]

There is http://www.svp-team.com/ - you can try at least, perhaps it can hide most of artifacts...