What exactly does ReClock do?

[dansrfe]

What does ReClock do, is it worth it to use it, and what settings are optimal for it? I am sure a lot of people will think I've gone insane because I don't know what reclock is but seriously it's a bit confusing as to the benefits it has versus directsound or something simpler I think. Thanks.

[Razoola]

In the most simple terms it slightly speeds up or slows down video to match your monitors refresh rate. It then resamples audio to keep lipsync with these slight changes in video speed.

[dansrfe]

So if I don't use ReClock then what does all the framerate adjusting and audio resampling? The renderer or decoder? Or does DirectSound "attempt" to do it? Also are there any disadvantages to using ReClock vs. DirectSound?

[burfadel]

Reclock and Directsound are not comparable as they are for different purposes.

Reclock changes the speed of the video, and thefore needs to change the speed of the sound so its not (expletive - ed) :)

Directsound is merely a sound renderer in Windows.

The benefit of reclock is it can make the motion smoother when the refresh rates aren't compatible (for example, 23.976 played through a 100hz monitor). In this case reclock would increase the speed to 25fps and adjust the sound according. Thats around a 4 percent speedup, and although you can notice it when played side to side, its not noticeable if you just watch it! This if the method utilised by tv stations in PAL 50hz countries when playing NTSC based material. It is actually better as it makes the picture silky smooth :).

[adam777]

As a follow up question, considering my screen is a laptop LCD screen with a fixed 60Hz refresh rate, will I benefit anything by using ReClock, as most of the stuff I watch is 24/23.976 fps?

[dansrfe]

^ yep I have the same question.

[leeperry]

considering my screen is a laptop LCD screen with a fixed 60Hz refresh rate, will I benefit anything by using ReClock, as most of the stuff I watch is 24/23.976 fps?
a mixture of Reclock+madVR will make sure that you get a very constant 24fps@60Hz judder...this would be completely unacceptable to someone who watches his movies in a 24Hz multiple, but you might like it better.

and if you have any 29.97fps video, they will be DEAD smooth :)

[Mark_A_W]

The benefit of reclock is it can make the motion smoother when the refresh rates aren't compatible (for example, 23.976 played through a 100hz monitor). In this case reclock would increase the speed to 25fps and adjust the sound according. Thats around a 4 percent speedup, and although you can notice it when played side to side, its not noticeable if you just watch it! This if the method utilised by tv stations in PAL 50hz countries when playing NTSC based material. It is actually better as it makes the picture silky smooth :).


No, that's a later add on feature.

The original (and primary!) purpose of Reclock is smooth playback, at the original speed.


It works well with madVR.

It causes havoc (in my experience) when you try to play 24fps at 60hz.

But it does work very well at converting 25fps movies to 24fps, and I do use it for that.

[dansrfe]

So what can I do for a situation when I'm playing 24fps video on a 60Hz locked display?

[Mark_A_W]

Buy a new display.

[dansrfe]

So basically for anything that isn't a multiple of 59.94Hz, it won't sync perfectly. The only added benefit for reclock in that situation is that it will maintain a more accurate clock and sync at the video's own framerate correct?

[foxyshadis]

Reclock is also much higher precision than older renderers; it used the sound card for frame timing, whereas in XP DShow uses the video card (starting with Vista DShow started using the sound card timer). There's a huge difference in frame timing jitter, the precision of the video interrupt is pretty coarse.

None of that makes a difference in newer windows versions.

Reclock can dynamically adjust your monitor's timing to be a multiple of a video's, btw. It doesn't always work, but when it does, it makes a difference.

[Mark_A_W]

(responding to dansrfe)

You'll have to try it and see.

Last time I tried it created a mess.


I'm idly looking for a cheap 22-24" 1920x1080 LCD that is 24p capable, to use as a preview monitor for the day that I swap my CRT projector to a digital.

[Mark_A_W]

Reclock can dynamically adjust your monitor's timing to be a multiple of a video's, btw. It doesn't always work, but when it does, it makes a difference.

Yes, I have used that, driving powerstrip.

But it won't help with a fixed 60hz display and 24fps material...

[leeperry]

Reclock is also much higher precision than older renderers; it used the sound card for frame timing, whereas in XP DShow uses the video card (starting with Vista DShow started using the sound card timer). There's a huge difference in frame timing jitter, the precision of the video interrupt is pretty coarse.

None of that makes a difference in newer windows versions.
Actually, the "slave reference clock to audio" option in Reclock is only here for debugging purposes(and for the bitperfect-obsessed ppl too :D)

Vista/W7 provide native HPET support(that has a much tighter granularity than anything XP will ever be able to offer: http://www.microsoft.com/whdc/system/sysinternals/mm-timer.mspx). Reclock by default will base its timings on HPET on Vista/W7, and the RTC clock on XP...but if you add "/USEPMTIMER" in your boot.ini, XP/Reclock timings will be based on the "ACPI timer"...which is much more accurate/stable and doesn't depend on the (jittery) CPU clock speed. the "PM Clock" is a strong asset to Reclock on XP :cool:

[namaiki]

It causes havoc (in my experience) when you try to play 24fps at 60hz.

Which video renderer in particular?

[adam777]

So basically with 24p and 60Hz I get to make sure my poison is served as it should... nice :)

[Jong]

It causes havoc (in my experience) when you try to play 24fps at 60hz.This should not happen and does not here with an EVR CP, although there may be specific problems with madVR.

In fact playing 29.97 and 23.976 material @60hz was the main original reason for the speedup option in Reclock, if you look at the readme. It pre-dated modern displays and was there to "smooth out" NTSC sources on 60hz monitors.

I would suggest anyone tries it. Normally it should work and give you a perfect 3:2 cadence with a 60Hz display. You must make sure that "guess a better media speed when hardware refresh rate does not match" is ticked (for a while it was not the default, so some old installations may have it unticked).

[namaiki]

This should not happen and does not here with an EVR CP, although there may be specific problems with madVR.

If it helps, on my system, I prefer madVR v0.17 (or maybe v0.16) compared to the newer ones for 24fps@60Hz.

ohohoho~

[oddball]

My main issue with ReClock is with bitstream audio. I don't know if anything has changed but from what I understand ReClock has to chop up the bitstream audio and drop frames to match the video and keep it in sync. This results in audio artifacts (Especially noticeable on music).

[Jong]

It doesn't chop up the audio. For bitstreamed audio it takes the original packets sent from the player and drops/repeats them as needed to keep audio and video in sync. The packets that do make it are completely unaltered. but, yes, it is much less than ideal and "not recommended".

However, the PCM resampling has been dramatically improved over the last year or so, so the best approach is simply to decode in the player and let Reclock resample and output multi-channel PCM for analogue conversion or pass out over HDMI.

But if you really are committed to bitstreaming compressed audio to an AVR Reclock may not be for you.

[Mark_A_W]

I can't remember - I tried this years ago.

It probably would have been Haali or VRM9.

If it works now, please ignore my comment.

[adam777]

OK, did some testing.
It turned out that both ReClock and MadVR report my display as actually running at ~59.8Hz, not 60Hz.
Considering this, will using ReClock benefit my setup in any way? (Watching mostly 23.976/24 fps material).
I may miss the point completely, but It seems that I get no delayed/dropped frames with ReClock either on or off, according to madVR.
Thanks.

[Jong]

I believe Madshi has said that his delayed/dropped counters do not help you in this situation. They tell you if rendering delays lead to a drop not if frames are dropped due to mismatched rates.

In answer to your question, yes, Reclock is absolutely designed to help where refresh rate and frame rate are not exactly compatible, but you really must decode audio on the PC and send Reclock PCM audio for it to work effectively.

[Blue_MiSfit]

I use reclock frequently for watching content that was originally 24p but then "sped-up" to PAL / 25p. The pitch shift is absolutely intolerable to me, so reclock does a very nice job of reversing this brutality :)

I also have a 60hz display, so it supposedly helps things smooth out a bit. I don't really notice that though. I think it's mostly placebo (for me anyway). I know there are mathematically visible improvements, but not so much perceptible to me :D

Derek

[Jong]

I use reclock frequently for watching content that was originally 24p but then "sped-up" to PAL / 25p. The pitch shift is absolutely intolerable to me, so reclock does a very nice job of reversing this brutality :)

I also have a 60hz display, so it supposedly helps things smooth out a bit. I don't really notice that though. I think it's mostly placebo (for me anyway). I know there are mathematically visible improvements, but not so much perceptible to me :D

DerekIt is not just mathematical. Without Reclock your PC will need to repeat a frame once every 1000 frames to keep sync due to the difference in frame rate and refresh rate. There may also be more judder caused by clock disagreements, but they will vary from system to system and may not affect you. All this will cause brief judder. Whether noticeable of course will depend on your sensitivity and what is on screen at the time when it happens. Slow pans are normally the worst for spotting judder. The inevitable 3:2 pulldown judder caused by playing 23.976@59.94Hz or 24@60Hz can also make the extra judder of 23.976@60Hz a little more difficult to spot.

Be careful about using the "time stretching" code in Reclock. If you use Reclock to slow down PAL media to 24fps that is good. The audio will be resampled to the correct pitch and nothing nasty happens. However, if you use "time stretching" to play @50Hz but with pitch "corrected" audio the 3D qualities of a 5.1+ soundtrack are destroyed by the process. The audio is literally cut up into chunks and each pair of speakers processed separately. this not only introduces artifacts at the point of the cuts but destroys the "phase coherence" between the front, rear, center and sub speakers. You may not notice the "cuts", the effects are quite subtle, but even if the "quality" of each channel in isolation sounds perfect you will not be able properly locate sounds in a 3D space. It is like having your speakers out of phase only the phase will vary in and out over time! It really is not a good idea.

[THX-UltraII]

James (ReClock author) says that the only purpose of ReClock is to avoid the chipmunk effect but I am a bitstream believer (I want my high end Marantz reciever to do the DTS-MA/True-HD/DTS/DD decoding) so it is not possible to do PAL-speeddown. Some guys on the Slysoft forum believe that you still benefit from ReClock when bitstreaming. What do you guys think about this?
for the information: I use a perfect matching display/source setup; my display device (JVC HD750 projector) can handle all profiles I made with ATI (23,976Hz for non-EU HD movies, 50Hz for EU HD movies and 59,976 for TV material).

[Mark_A_W]

The purpose of reclock is to reclock the audio to match the video, to get smooth playback.

This can be done with bitstreaming (but PCM is BETTER). With bitstreaming you will get dropped or repeated packets.


While madVR has made big strides, it's basically impossible to get smooth playback on a PC due to the multiple clocks involved, without Reclock.

[THX-UltraII]

The purpose of reclock is to reclock the audio to match the video, to get smooth playback.

This can be done with bitstreaming (but PCM is BETTER). With bitstreaming you will get dropped or repeated packets.


While madVR has made big strides, it's basically impossible to get smooth playback on a PC due to the multiple clocks involved, without Reclock.

But isn t it so that when I bitstream and you own a high-end dedicated HT-receiver, you will have a result of better AQ?
And if I bitstream and I use a perfect matching output (1920x1080@23,976 with ATI CCC) and input that accepts this signal (my projector) I get judder free and perfect smooth playback?

[Mark_A_W]

No. The audio clocks and video clocks run at different speeds. You will get jerks and jumps. It is inevitable.

Did you read the Read Me file that comes with Reclock?


But yes, you could argue that unmolested audio is better. I have a pretty high end fully active Focal driver based audio system and I can't tell if Reclock is running, but you might have ears like leeperry...


See how you go with madVR. But madVR and Reclock is better. Nothing is perfect so far.

[THX-UltraII]

No. The audio clocks and video clocks run at different speeds. You will get jerks and jumps. It is inevitable.

Did you read the Read Me file that comes with Reclock?


But yes, you could argue that unmolested audio is better. I have a pretty high end fully active Focal driver based audio system and I can't tell if Reclock is running, but you might have ears like leeperry...


See how you go with madVR. But madVR and Reclock is better. Nothing is perfect so far.

But I ve looked so closely during a movie but can t find any jumps or jerks at all when bitstreaming.

[namaiki]

If your monitor's refresh rate is *perfect* it could be possible.

[THX-UltraII]

btw, what about a combination of Bitstreaming AND using ReClock? (checking the option enable bitstreaming op ReClock which isn t recommended by James :)) Wouldnt you get both the benefit of perfect sync AND bitstreaming? The only thing you wouldn t have than is PAL-speeddown

[THX-UltraII]

If your monitor's refresh rate is *perfect* it could be possible.

But when do you know it s perfect/how do you check your monitors detailed refresh rate?

[namaiki]

But when do you know it s perfect/how do you check your monitors detailed refresh rate?

What does Reclock filter properties report for "Refresh rate"?
e.g. for me, it reports 59.600Hz (DDR)

btw, what about a combination of Bitstreaming AND using ReClock? (checking the option enable bitstreaming op ReClock which isn t recommended by James :)) Wouldnt you get both the benefit of perfect sync AND bitstreaming?
If it's not perfect, the sound might stutter. As said above, "With bitstreaming you will get dropped or repeated packets."

[THX-UltraII]

Ok, I m going to give PC-decoding another try tonight. It s been a while since I configured my system for this. Can you guys help me on my way? I use ffdshow as audio decoder.

[janos666]

I am using FFDShow and MPC-HC with MadVR 0.23 and I am considering to use ReClock with these softwares.

Does ReClock have any benefit for 23,976fps materials and a display which reports 59.95Hz (MadVR says...)? ReClock would speed up the video to 24.000fps.
Another option is to set the display to 24.000Hz and let ReClock to speed up the playback to 24.000fps. But my display has a fixed 60Hz LCD panel (I am not sure about the exact number. It can be either 60.000 or 59.95 as welll...). So, this 1080p24 mode is only virtual, any the internal processor will do the frame rate conversion. (It is a Dell U2410, by the way.)
I can't see any real differences between these settings. Which is theoretically better?

But I can see some weird things in ReClock CP during playback:
Video Stream: 23.976 fps, 1920x1080p, YV12 12 bits

This is a Blu-Ray video, decoded by FFDShow. Shouldn't it be YV12 8 bits?

I guess it would be a better Audio renderer either with or without using the speed controls. Isn't it?

[nurbs]

YV12 is 12 bits per pixel and that's what basically all available video (DVD, Blu-Ray, online video,...) uses, so I don't see a problem there.

[leeperry]

This is a Blu-Ray video, decoded by FFDShow. Shouldn't it be YV12 8 bits?
8bit in YCrCb doesn't equal 8bit in RGB

see it as converting 32/64bit float audio to 16/24 bit integer, there's a million ways to do it: http://en.wikipedia.org/wiki/Dither#Different_types

[janos666]

Ok. So, it is not a problem.

Does anyone have a good 23.976fps tearing test video?
Reclock has a tearing test but it doesn't work when you do not change the media speed. So, it is useless for comparison.
MPC-HC has another one but it doesn't work with madVR.

The tearing test in ReClock (with 24.000fps speedup from 23.976fps) shows me that the 1080p24 display mode is better than the 1200p60 mode. (Even though the panel is fixed to 60Hz, so the internal processor will do FRC.)

[Blue_MiSfit]

I think it's really important to point out that playback jitter is a huge deal to some, and a non issue to others.

I'm not someone who minds a skipped / duplicated frame every 1000. In fact, I'd be quite hard pressed to even notice it. Do I like the idea of it not happening? Of course :p

But, there are plenty of folks who are quite sensitive, so I'm glad there are tools like this and MadVR to smooth things over for them.

[dansrfe]

The best solution of course is to playback the video on a display with a refresh rate that is a multiple of the fps. Do the Panasonic plasma 3D tv's have adjustable refresh rates? Like 120Hz for film speeds and 100Hz for PAL speeds?

[Mark_A_W]

I dunno about the 3D ones, but my Panasonic Plasma runs 1920x1080 at 24p (displayed at 48hz), 50p and 60p.

[oddball]

Yes I am trying to run it at 50p/Hz with 25p sources. I have fixed the constant judder (I had to force secondary monitor as it was syncing to the 60Hz PC monitor instead of the HDTV. I turned off vsync presentation in MPC-HC and set ReClock for vsync. I get much smoother video playback now on PAL sources and checking the EVR-Sync stats I get 0 dropped frames, it presents at close to 100% 25FPS and stats shows a near perfectly smooth red vsync line.

HOWEVER.

While I have these stats up on screen I still see the odd jerk/pause/glitch in video playback. At 24p/Hz I don't get this at all (Unless some background process interferes or I do something else like browse a webpage during playback).

It's just the odd video pause even though there are 0 dropped frames and vsync looks fine. Most peculiar.

EDIT: I just tried that problematic source I linked a sample to above again and the red and green line spike up and down all over the place and it still plays back all jerky and out of sync. I think that source is just a bad source though as other sources seem a lot smoother (But not perfectly smooth).

I think I will just stick to slowing down PAL sources where I can as I don't come across much 'native' PAL stuff anyhow. Slowing down native PAL to timestretch it is just as bad as speeding up Non-PAL with incorrect pitch in some ways (I tried it on a native PAL source the other day and it was like time had slowed down. Which it had obviously. Even though the video played smooth and the audio was the correct pitch. It just felt 'wrong').

[Mark_A_W]

Try madVR instead of EVR-Sync.

[oddball]

MadVR gives me problems on certain sources. It turns into a slideshow. My G210 is not quite up to the job or something.

[namaiki]

MadVR gives me problems on certain sources. It turns into a slideshow. My G210 is not quite up to the job or something.

I wouldn't be surprised. My GeForce 9600M GT is only just up to scratch for 30fps 1080p playback using madVR.

[TinTime]

MadVR gives me problems on certain sources. It turns into a slideshow. My G210 is not quite up to the job or something.

Have you tried using bilinear scaling with madVR? That shouldn't be too taxing.

[nogo]

Bookmarking

[amayra]

i hope i see 64bit reclock in the future