Jerky Panning

AnnaMayBelle · Post by **AnnaMayBelle** » Sun Mar 05, 2006 9:12 am

I finally completed the remastering of an AMV now that I've read Ermac and Absolute Destiny's guide. Unfortunately, I've noticed a problem in the opening scene... The opening scene is a horizontal pan, and while the rest of the video is perfect, the pan is slightly but steadily jerky.

I'm told that this has to do with the way TV screens and monitors refresh and draw each line, but on the other hand, the original, lower quality version of the AMV did not have this jerkiness.

The footage is progressive (originally interlaced), edited in 24fps and later converted to 23.976.

Any solutions would be much appreciated.

Zarxrax · Post by **Zarxrax** » Sun Mar 05, 2006 12:57 pm

Ok, there are a number of things that could cause this. The most obvious is, have you adjusted the speed of the clip in your editing program? This would definately cause jerkiness.

If thats not the case, then its an issue with how you have prepared your source. Some DVDs are hybrid, which means that they have some 30fps parts and some 24 fps parts. The openings and closings of anime, and sometimes specific shots in the anime such as pans, are done at 30 fps. When you decimate down to 24fps, this would cause jerkiness on such scenes.

One possibility is to make a new avisynth script without the decimation, and see if it looks jerky there. If it looks fine, then just add the line AssumeFPS(23.976) [or 24, whichever you are using] after it, and then use that clip for the specific section of your amv.

AnnaMayBelle · Post by **AnnaMayBelle** » Sun Mar 05, 2006 6:59 pm

It seems all of the Wolf's Rain chapters, regardless of scene, run at 29.970... This of course includes my jerky pan, and all of the rest of the footage that's smooth-as-silk. I followed your instructions about AssumeFPS without decimation, and I still end up with jerky footage...

When I watch the scene on DVD, I feel that even in the original it is very slightly jerky, though not as much so as my my ripped, deinterlaced version.

TaranT · Post by **TaranT** » Mon Mar 06, 2006 12:10 am

This is very common in my experience and - as you noticed - shows up even when you're watching the original DVD material on a TV.

Suggestion: put the clip on the timeline (or use vdub) and take some still pics from the start and end of the panned scene. Take pics from the middle if you need them. Try to capture the best quality pics you can. Then use the panorama stitching function of a photo editor to glue those pics into a large, wide (or tall) picture. Clean up the joins if necessary. Then put that large pic back on your timeline and use motion settings to generate the pan.

AnnaMayBelle · Post by **AnnaMayBelle** » Mon Mar 06, 2006 1:02 am

TaranT, I appreciate the suggestion, it had actually occoured to me. But unfortunately, the horizontal pan has snow falling vertically throughout the scene.

Thus, stitching the pictures together to make a new panorama is impossible.

Strangely, when I render it in Indeo just to see how it looks, it's considerably smoother... It's when I make an uncompressed and convert it to MPEG2 that I have a problem. I'd like to just be able to find a codec that most conventions will accept... And unfortunately the first con I plan to enter this is a very small con and they've had compatability issues in the past. Last year a friend of mine had to help them get their computers to play mpgs!

Does anyone have any other common codec suggestions?

Zarxrax · Post by **Zarxrax** » Mon Mar 06, 2006 12:39 pm

The codec that you use has absolutely no effect on smoothness. There is likely some framerate conversion happening somewhere that causes it.

You say you have the problem when you export uncompressed and convert to mpeg2...

Does the uncompressed video itself have the problem? If you step through frame by frame in virtualdub, do you see all the frames?

AnnaMayBelle · Post by **AnnaMayBelle** » Mon Mar 06, 2006 8:40 pm

I just went through the uncompressed video, frame by frame in VirtualDub, and it's smooth as silk... not a single jump.

Zarxrax · Post by **Zarxrax** » Mon Mar 06, 2006 9:37 pm

Ok, so your uncompressed file is 23.976 fps, and plays fine? I assume you are encoding the mpeg2 at 23.976fps as well, with 3:2 pulldown on playback?

Maybe your pc just has issues playing the mpeg. Try loading it up through avisynth and go through it frame by frame in virtualdub and see if all the frames are there. I know it sounds strange, but weirder things have happened.

AnnaMayBelle · Post by **AnnaMayBelle** » Mon Mar 06, 2006 9:45 pm

All the frames appear to be there in VirtualDub.

Ever since installing AMVapp on my computer, I haven't been able to get MPEG2s to play. They're just black screen with no audio. In addition, thumbnails of HuffYUV files make Windows Explorer crash. So, I've had to do all of my MPEG2 watching on either Ma Belle's computer, or my dad's computer. Ma's computer is slower than mine, while dad's computer is faster and has a FAR better video card. Both of them experience the jerkiness in the video, but not in any other MPEG2s we've watched, and even in the video in question, it's only on the opening pan shot. The rest of the video is smooth as silk.

Scintilla · Post by **Scintilla** » Tue Mar 07, 2006 1:59 am

AnnaMayBelle wrote:Ever since installing AMVapp on my computer, I haven't been able to get MPEG2s to play. They're just black screen with no audio. In addition, thumbnails of HuffYUV files make Windows Explorer crash.

Try disabling ffdshow's support for HuffYUV and MPEG-2. That often solves this kind of problem, it seems.