OT: 24(5)p panning judder -I'm lost!

megabit wrote on 9/9/2008, 5:14 AM

I have this huge 50" plasma hooked up as the Windows Secondary Display to my Vegas installation, and I cannot get rid of the jerky motion of my 25p material displayed on it!

Let me make it clear: I'm talking the EX1 HQ 10080/25p, and Vegas Preview Window says it is capable of full 25 fps (to make sure, I switched from Best/Full to Preview/Half - still the same).

No matter how slow my pans/tilts/zooms are, the just cannot play back smoothly full screen - whether I render them out to HD or SD, they will be jerky when played back full screen, and as smooth as silk in a smaller window... (e.g. in WMP or VLC).

I am tending to suspect now that all this "how smooth 24(5)p panning can be" discussion can be boiled down to just "how fast my graphics card is" (or is it the display itself?).

Can those who are using some special cards like e.g. BM Intensity tell me: do you also witness the motion jerkiness when playing back 24(5)p full screen, and smooth motion when reduced to a smaller size (don't even know if the latter is possible with those cards)? Yes I know the Intensity doesn't support 1080p, but really - it doesn't matter; 24(5)p can be displayed both ways (i.e. as 1080p or 1080i), and the results are the same.

Comments

megabit wrote on 9/9/2008, 6:00 AM

Just to bump it up a little, and to reduce my probably somewhat unclear message to these 4 points:

- the source (camera)? - doubt it, as it can play back smoothly in a window, in whatever format you render it to

- the software player? - doubt it, as it's the same with Vegas timeline AND with WMP, VLC, PowerDVD, etc...

- the graphic card? I don't know, as my ATI HD 3870 is not a bad one

- the display? I doubt it, as it plays HD broadcast perfectly smooth!

So, what is the culprit in 24(5)p jerkiness? Opinions welcome!

farss wrote on 9/9/2008, 6:21 AM

Assuming the following:

1) You are not exceeding recommended panning, tracking or zooming speeds.
2) Are not using shutter angle smaller than 180deg.
3) Vegas is feeding 25fps to the display.
4) The refresh rate of your display / graphics card is a multiple of the frame rate.

Then you need to dig further.

1) There's a long list of things in the image that can affect judder.
2) There's a list of things regarding the display and it's environs that can affect judder.
3) The display itself could be to blame also.

Have you tried watching a movie off air on the same display under the same viewing conditions? Our Sony HDTVs when watched in our office display movies as a juddery mess.

Apart from all the more obvious factors even edge detail settings can lead to bad motion rendition.

Bob.

farss wrote on 9/9/2008, 6:24 AM

Well you answered one of my questions.
Just to refine them though. The monitor is connected to the PC via HDMI or DVI right. Therefore the display refresh settings in Windows is driving the monitor's refresh rate, most likely 60Hz. Try changing it to 50Hz if you can.

Bob.

megabit wrote on 9/9/2008, 6:31 AM

Of course I'm outputting at 50 Hz (the ATI Catalyst software can enable this); what's more my display (the Panasonic Viera) refreshes at 100 Hz.

As I said - I personally am tending to blame the graphics card, but am not sure about it...

farss wrote on 9/9/2008, 6:40 AM

I don't see how it COULD be the video card. Vegas writes 25 fps into the video RAM. The video card sends that out the DVI port. It does zero processing. If you were playing a video game where the video card does most of the hard work then it's a totally different scenario.

Bob.

megabit wrote on 9/9/2008, 7:27 AM

Bob,

With the other three potential reasons pretty much excluded, too - that's why I said what I said in this thread topic: I'm lost!

And the most mysterious part is that the window does not have to be really small to handle the 25p motion smoothly; it's enough to play it inside the VLC window, for example (as opposed to Full screen, or Kiosk, mode) - the window itself may be maximized!

The same applies to Vegas: when I use my plasma as the Secondary Windows Display, it's jerky; when I drag the Preview Window to it instead - it's smooth even with the window maximized!

Could it be the DirectDraw Overlay handling by ATI drivers?

megabit wrote on 9/9/2008, 8:26 AM

"Could it be the DirectDraw Overlay handling by ATI drivers?

Well, just tried using the same 24", 1920x1200 monitor that Vegas GUI runs on (instead of the plasma - just changed to it in the "Preview Device Preferences" drop-down list).

Even though it's also full screen, full 1920x1080 - the judder is NOT there! And this is also played back using the DirectDraw Overlay ...

Which again points to the (secondary) DVI ->HDMI -> Panasonic 50" HDTV chain as containing the weak link... Only it plays BluRay movies and/or broadcast HD without any judder!

I'm afraid I've run short of ideas. Other graphic/video cards users - please chime in !!!

Terry Esslinger wrote on 9/9/2008, 9:36 AM

Just to be clear, does this 'jutter'' happen just on panning shots or also on still shots with something moving rapidly within the scene?

JJKizak wrote on 9/9/2008, 9:42 AM

Could there be something in the Panasonic menu that has to be re-adjusted when inputing from Vegas?
JJK

TheHappyFriar wrote on 9/9/2008, 9:52 AM

so it judders while using the plasma as a preview but not when using the DVI->HDMI converter?

sounds like an interlace issue. The TV either thinks it's supposed to interlace or the adapter is sending interlaced.

megabit wrote on 9/9/2008, 10:12 AM

No, I don't think it's an interlacing-related phenomenon. The plasma reports the input from Vegas (or indeed from Windows secondary display, for that matter) properly, i.e.:

- as 1080p when fed through DVI->HDMI,
- as 1080i when fed through component.

In the ATI Catalyst Control Center, I have de- interlacing set to OFF for both scenarios, as I am using 25p (treated as 25PsF in the latter case).

In both cases, the judder is the same. Also, it affects panned / zoomed scenes as well as quickly moving objects...

TheHappyFriar wrote on 9/9/2008, 10:41 AM

Even if it's not hardware, it really sounds like interlace issues.

Can you use your HD camera & get ~15 seconds of footage looking @ the plasma?

megabit wrote on 9/9/2008, 10:45 AM

Yes, I guess I can do that... not tonight, though.

Thanks for your willingness to help!

John_Cline wrote on 9/9/2008, 1:32 PM

THERE IS NOTHING WRONG WITH YOUR TV SET OR YOUR VIDEO CARD!

24p or 25p IS going to judder during pans and motion. If you don't want that stuttering effect, then shoot at a higher frame rate. It's all about temporal resolution and 24 or 25 frames per second IS NOT fast enough to produce smooth motion.

The 24p frame rate was originally conceived as the slowest film frame rate they could get away with and still have a semblance of motion fluidity. Film was (and is) expensive. The decision was PURELY economic. It's 2008, 24p needs to die!

JJKizak wrote on 9/9/2008, 1:41 PM

Amen!
JJK

megabit wrote on 9/9/2008, 2:02 PM

"THERE IS NOTHING WRONG WITH YOUR TV SET OR YOUR VIDEO CARD! "

Really? So why is that the same material played in a smaller window has no judder?

I mean I'm perfectly aware of 24(5)p shooting technique, and with this thread didn't intend to beat the dead horse again, but try and draw your attention to the playback hardware/software chain as being the judder source.

Interestingly, when I play from Nero Showtime with hardware acceleration OFF, the jerkiness is much less - even in fulll screen. Go figure.

With acceleration on, it seems like the graphics card is unable to change the huge screen content fast enough; parts of the image lag behind as a result...

farss wrote on 9/9/2008, 2:28 PM

What resolution is this big screen being driven in?

Single link DVI pegs out at 1920 x 1200, you need dual link DVI to go beyond that.
Also as Vegas would only be sending 1920x1080 there might be scaling required. That would increase the load on the GPU.

Probably you need to do more in depth diagnosis.

Build a video where each frame has burnt in time code.
Put EX1 into Clearscan and video the display, check video frame by frame to see if the problem is due to dropped frames or something else.
Have you tried turning Off the 100Hz interpolation in the display. I've seen reports indicating that can really mess things up.

Bob.

megabit wrote on 9/10/2008, 12:23 AM

Bob,

Thanks for sound and constructive advice - I'll do the testing soon.

As to the display: it's 1920x1080, so no scaling is required (I have it turned off in the Preview Device Properties). Also, it doesn't do any interpolation - each frame is simply displayed twice in 100 Hz refresh mode (basically, it's a PAL TV, so it operates at 50 Hz; the 100Hz mode is there only to reduce flicker).

Piotr

megabit wrote on 9/12/2008, 4:53 AM

Just to report, that - due to some absolutely unknown reasons - the Secondary Windows Display on my 50" HDTV plasma is now as smooth as silk with the 8.1 64bit Vegas Pro release.

OS / application / graphics memory conflicts with 32 bit version?

Perhaps. Go figure.

PS. So far, the only other advantage of the 64bit version is that - with a couple of Vegas 8.1 instances open - I can switch between them (or use any other Windows app) - without waiting as long as I had to with the 32bit version. Timeline playbeck fps, or rendering speeds, didn't improve noticeably though (well, that's what we expected).