View Full Version : Ghosting, why am I seeing it?
December 26th, 2008, 11:35 AM
I went to BestBuy and shot some demo footage on my own SD card to compare at home. Camer was Canon HG20.
Obviously I shot in all 3 modes: 60i, 30p and 24p. When shooting 24p I took a mental note to be very still and not move around. I even took a still shot: No panning, no zooming - nothing just a guy went by and it was ghosting.
I used Prospect HD to remove pulldown and then when intoto PPro CS3 1920x1080 23.976p and the file was native and already there I saw people walking by and ghosting.
what what is going on? WHat is a point of shooting 24p even if on steady cam when someone walks by there is ghosting. You don't see it in the movies. Is it possible that HDLink is not removing 3:2 pulldown correctly?
December 26th, 2008, 11:49 AM
what are you capture setting? Screen Grab the settings window (Alt+Prnt Scrn) and post it here.
December 26th, 2008, 11:59 AM
here it is
December 26th, 2008, 12:09 PM
In the Pre-compression area you might try checking deinterlace...
December 26th, 2008, 12:29 PM
I was testing to see that deinterlace was not selected and that is the most common user error -- never mix deinterlace with pulldown removal for 24p in 60i.
Mario, not sure what is going wrong. Can you capture a 10sec sequence to M2T and post that so we test the source.
December 26th, 2008, 03:03 PM
Ok I never posted video so I will just give you a link to 2 files from my web page.
One is exported cineform avi file around 72MB and the other is m2v ts mpeg around 11mb
hope this works
December 26th, 2008, 03:10 PM
sorry the other link for mpeg would not work try this and it is only 6mb
December 26th, 2008, 08:57 PM
This sequence doesn't have pulldown, so if you stop trying to remove the pulldown the frame rate will be fine. In the next release we detect the error of trying to remove pulldown from a 24p source. The camera you mention is AVCHD, yet you have offered an MPEG clip, why is that? Other confusing things, the CineForm AVI has an AC3 track, so that should not have come out of HDLink. It seems now of this data is camera original, all been preprocessed somehow. The camera should be MPEG4 with a .MTS extension.
December 26th, 2008, 10:29 PM
Ok First thing, it is Canon HG20 (like HF11 and HG21) it has an option of shooting 60i, 24P and 30P. I shot the first thing in 24p mode.
I used PPro CS3 with Export to "Adobe Media Encoder". Normally this file was m2v but when I had that as a link, it did not want to download so I renamed it as mpg. If I had Audio in it it would have become m2t file. The reason it has AC3Filter is because originally when I used HDLink there was no audio when converted so I read few forums and installed CCCP and AC3Filter. Now I get Audio during the HDLink conversion.
That is also why I offered cineform avi file that was an export
I can give you access to mts file but it is 300MB because I shot it for 3-4 minutes. I don't know how to split AVCHD mts file into smaller parts. My workflow is: Copy mts files from SD cards, Use HDLink to change it to AVI and then edit in PPro CS3 and export to (usualy m2t files - I have Avelink2Player that plays them then directly from my PC)
but I can try to give you access to MTS file here, but it is 300MB. I had to zip it so it would be downloadable extension
December 26th, 2008, 10:41 PM
I think I get what you were saying, you wanted to see my original mts file from the start. I understood that you wanted my "HDLink converted" files so I did it with the pull down then put it on the time line in PPro and shorten it to 10 seconds and exported it into mpeg and also cineform avi (which was 70mb)
but unfourtanetly if you wanted to see the original mts file from the Camers then you have to download the 300MB zip file from the above post. My upload speeds on the servers are around 1-2Mbps, so it will take you probably take you... wow (just did the calculations) a lot of hours 25 hours?
Unless there is a tool that could allow me to split the mts file into 10 second chunks???
December 26th, 2008, 10:45 PM
I thought you had a conversion issue, and only the source can help with that. Sounds like you have or had a bunch of missing components, maybe you should wait for support to return Monday. Chop up an MTS file with any file chunker. That Zip file is taking too long to download, I only need the first 10-20MBs.
Our posts crossed. If you can send chopped up source data that would be best (first 10 second is fine.)
December 27th, 2008, 11:38 AM
The download completed last night, and the conversion and pulldown removal worked perfectly. Which AVC Decoder are you using?
December 27th, 2008, 12:18 PM
The Canon HG is hard drive / file-based, not HDV tape, so if you shoot 24p, then it probably doesn't require pulldown.
Have you tried to simply uncheck the "Remove pulldown" option ?
December 27th, 2008, 01:11 PM
It has pulldown, Mario just sent the wrong clip.
December 27th, 2008, 01:25 PM
When I start HDLink and look at the log during the conversion it says "Adobe AVC decoder" I bought coreavc, I have CCCP and ffdshow but I wouldnt even know how to tell HDLink to use another one. I uninstalled CCCP and Elecard but to no effect.
When you remove pulldown, do you see ghosting when people walk?
December 27th, 2008, 07:26 PM
The Adobe AVC Decoder is fine (CS4 is not.) The pulldown is removed correctly. When comparing the 60i to resulting 24p extraction, there is zero motion blur added. The is some frame presistance inherent in the camera, no more than I've seen in all the sub-$1000 progressive cameras.
December 27th, 2008, 08:58 PM
so basically 24p on Canon's is useless (which goes for all the HV-20,30 and HF100, 10 11 and HG-20 and 21 :)
December 27th, 2008, 09:53 PM
Not at all, I would shoot all of them over any interlaced source. It just not film, or digital cinema.
December 27th, 2008, 10:41 PM
Hey, Mario. I think what you're seeing has less to do with Cineform and the original codec and more to do with what was shot.
If you have a guy walking from one side of the frame to the other, you might be seeing what some people call "motion jitter" and others call "ghosting" which is caused by how the subject moves across the frame. I'm sure you've heard or read this before, but shooting 24p video is more like shooting film than it is like shooting 60i video. There are rules to follow to avoid that "ghosting."
There's a bunch of threads on this forum that describe those rules so I won't bore anyone with the details, but the number one thing to avoid when shooting 24p is having the subject move across a static frame from one side to the other. Movement toward the camera and away from the camera is fine, but not across it. 24 frames just aren't enough to capture the motion correctly unless the subject is traveling at a pretty slow speed.
My suggestion is to go back to Best Buy and shoot someone walking towards the camera, walking away from the camera, and panning with the person as they walk by and see if you get the same results.
Sorry if you've heard this all before.
By the way, the HV30 (tape-based HDV) shoots pretty good 24p. I've use mine as a b-cam and mix it with my JVC HD250 after down-converting the video to 720 during capture with HDlink. Good job Canon and Cineform.
December 28th, 2008, 10:44 AM
now this makes sense what you are saying. But comon, I was watching few movies in the last days and I watched and paid attention to their movement and they did walk across the frames smoothly
But I can see how 60Hz indoor light and not paying attention to shutter could have caused the issues I had. Isn't there something that says I should use either 1/24 or 1/48 shutter speed?
but I still think that 60Hz light was the main cause of my problem
December 28th, 2008, 01:17 PM
Shutter speed can definitely cause issues. I shoot 24p exclusively at 1/48. 1/24 look really bad. Higher shutter speeds can give you less of that jitter but can cause the movement to seem less natural like that now classic "Saving Private Ryan" look. They used fast shutters in "Gladiator," too, to give that super-fast action look.
However, stuff shot on film still has a different look than shooting 24p video. We have to deal with those electonic related issues that film doesn't have. The motion issues we're dealing with seem magnified with 24p video. It's just one of the disadvantages of the format.
I remember watching a Hollywood film-originated romantic comedy with my wife (she likes that stuff so what can I do) and seeing that very motion jitter that we're talking about. It was far less noticable than it would have been if it were shot with 24p video, but it was still there. It actually made we feel pretty good. If they big boys still have to deal with it than I'm not such a bad shooter after all!
I've never really considered the lighting being a contributor, but it makes some sense to me that it might. Maybe someone else could jump in on that front.
December 28th, 2008, 04:20 PM
well 60Hz that is on and off every 1/60 of a second and you shoot 24, that can effect it
BUT about movies. I see it all the time and see more problems that are like "well they should have taken care of it"
like wrong clothes that will make video/film cause issues
panning I see all the time, especially on buildings, cities, they sometime do it just a bit too long at it is annoying (makes me feel better too that they miss it...)
also look at the headlights on the cars, they show reflections which is because of the lens
but just walking people weather close of far away I never saw ghosting there even across the frame wchich is common in the movies when they walk and talk.