"Ghosting" in the machine...

24Peter wrote on 4/6/2010, 3:56 PM
Any help would be appreciated...

I'm shooting with a 5DII. I'm transcoding the native .mov files in Vegas Pro 8 c using the Sony MXF HD EX 1920X1080 35Mbps template. I use the .mxf files to edit in Vegas and output to .mp4. I'm using a MainConcept AVC/AAC custom template - 1920X1080 23.976 (I'm using the new 24p framerate for my 5DII though I had similar issues with 30p) VRB (NOT two pass) 8M max 3.5Mbps avg. "Best" video quality.

The issue is: there is pretty bad ghosting on moving objects in the frame. In the most recent instance, it's kids swinging on a swing. Other than the ghosting, I'm quite happy with the codec - it actually looks quite good (slower movement is fine, but fast movement in the frame has really bad ghosting.)

I don't think the issue is 24p as I had the same problem with 30p files before the new firmware (and yes, I was matching the framerates with the 30p .mxf transcoded files and .mp4 final output files.) (I also owned a DVX-100 and HV20 and shot 24p with both for years so am familiar with the limitations of that framerate.) BTW - just to be clear, the camera is stationary - it's my subject that is moving within the frame.

The original .mov files show some ghosting but it is definitely worse in the final .mp4 output. On the other hand, when I render to mpeg-2 for SD DVD, the DVD's look quite good on my TV = ghosting is minimized. So it is viewing the .mp4 files on a computer that is the problem.

I tried rendering my .mp4's using the Sony AVC .mp4 codec, but it didn't help the ghosting issue and the rest of the output looked worse.

I'm shooting with 1/50th shutter speed on the camera. I would be happy with blurred movement as opposed to the ghosting/lagging latent image I'm getting. It's almost nausea inducing.

Any ideas?

Comments

Laurence wrote on 4/6/2010, 7:43 PM
Ghosting is almost always a result of not quite getting the framerate right. For example, choosing a 24p template when the actual frame rate is 23.976 or 29.97 framerate when the footage is actually exactly 30fps. This is one of the things (along with color range) that Cineform Neo Scene or Neo HD corrects when it is converting the raw footage into it's intermediate format.
24Peter wrote on 4/7/2010, 6:52 AM
Well as I said, I was careful about matching framerates... Has anyone else had ghosting issues either going from .mov to .mxf or .mxf to .mp4?
Ivan Lietaert wrote on 4/7/2010, 7:12 AM
Forgive me if I state the obvious, but have you 'disabled resample' on each clip?
farss wrote on 4/7/2010, 7:16 AM
"The original .mov files show some ghosting but it is definitely worse in the final .mp4 output. On the other hand, when I render to mpeg-2 for SD DVD, the DVD's look quite good on my TV = ghosting is minimized. So it is viewing the .mp4 files on a computer that is the problem."

Sounds to me like somehow you're getting things into interlaced and mixing up fields.
Aside from that I think the ghosting you're seeing in the original footage is due to the CMOS sensor. I've noticed this a little bit on the EX1 with slow shutter speeds. The 5D seems to have a longer sensor readout time than the EX which might make the problem worse. What I see is not exactly the same look of the motion blur you get with a global shutter like in a CCD camera.

Bob.

24Peter wrote on 4/7/2010, 7:51 AM
Disabling Resampling didn't help.

Here's an example:
Example
Laurence wrote on 4/7/2010, 8:00 AM
]>I'm shooting with 1/50th shutter speed on the camera. I would be happy with blurred movement as opposed to the ghosting/lagging latent image I'm getting. It's almost nausea inducing.

Your shutter speed should be 1/48 for 24p and 1/60 for 30p.
24Peter wrote on 4/7/2010, 12:21 PM
Close as I can get is 1/50th on the 5DII when shooting 24p. 1/60th for 30p, still get ghosting...
Patryk Rebisz wrote on 4/7/2010, 2:29 PM
what firmware are you shooting with?
farss wrote on 4/7/2010, 2:31 PM
Is that camera original?

If so you really need to sort out how you're using the 5D. There's horrid compression artifacts, the ghosting looks like ringing from too much detail enhancement, there's bad blocking in the shadows etc.

Trying to recompress that will footage will cause it to go downhill pretty badly, every defect will be enhanced.

Bob.
farss wrote on 4/7/2010, 4:57 PM
Apart from the observations above I had another look at this footage.

At full raster on a 24" monitor in a well lit room the motion judder is horrid. As I shrink the frame size of the preview monitor it gets better. This is I believe just part of how we perceive low frame rate images. I know you said you've shot 24fps before but in HD on a big screen the rules apply moreso. Aside from that though there does seem to be very little motion blur given a shutter speed of 1/50th. Are you certain the camera is under your control here.

Aside from that and pardon me if I'm telling you how to suck eggs but from what I know about getting the best out of the 5D you seem to have broken all the rules. Feel free to ignore this or seek better advice from people who've actually "done it" but I think you need to use a lower contrast setting, buy some ND filters to get the iris open more and reduce your depth of field.

Bob.
24Peter wrote on 4/7/2010, 5:19 PM
Firmware is 2.0.4

Bob - if you read my original post you'll see this is the .mp4 output from the transcoded .mxf files. The settings are listed there.

As for the camera, I shoot in manual mode - aperture was around F5.6 (I was shooting with a ND8 and CPL) and shutter 1/50th. Movie mode was 1920X1080 24p. The picture style I'm using is the flat style most of us are using - contrast and sharpening = 0, Saturation = 2. So I am not aware of the rules I have broken. If anything, I squarely in the most used settings for this camera.

So... any suggestions on how to process this footage to minimize the juddering?
farss wrote on 4/7/2010, 6:35 PM
Fair enough however I was expecting a shallower DOF.

I'm kind of out of ideas, you seem to be the second person having issues with the MXF codec causing problems and the last person (LarsHD) was able to show that Vegas was duplicating frames which would certainly make for some very juddery movement at 24fps.

Problem is without the source I have no way of knowing apart from eyeballing your footage what is going on. I took the file I'd downloaded and transcoded it to MXF 422 at 50Mbps and did a difference composite against the original and I didn't notice anything awry. This was with V9.0b.

As you have the original media can I suggest you do the same. To do this just put the new mxf video onto an upper track and set the compositing mode to Difference or Difference Squared. If you see any completely different frames then something is going seriously wrong. By itself transcoding to a different codec shouldn't make motion any better or worse and dropping or duplicating frames is all I can think of that'd cause a problem.

Bob.