How to place slow motion on top of normal footage?
by Doug Horton
on
Jun 9, 2009 at 4:50:07 am
So, the concept for this music video is to have slow motion of fighting happening behind the band who's sitting in front of this action. But it has to be filmed locked down without touching the camera, and filming the two clips seperately obviously. But what's the best way to place them on top of one another?
So the idea is the band is sitting on a hotel bed/furniture just loosely playing their song, and behind them is slowed footage of a fight...
just tryint to find out the best way to execute this. thanks!
Re: How to place slow motion on top of normal footage? by Stuart Elith on Jun 9, 2009 at 7:09:17 am
I think the two main ways to achieve these kinds of things are by rotoscoping, or greenscreening.
Roto has the advantage that you don't have to worry about color spill (things don't take on a green tinge) and in some cases you can use the real shadows and stuff like that, because the action was still filmed in the same environment.
Greenscreen is nice if you shoot it well, as you don't have to do all the manual roto work - even if the band aren't doing high-energy movements, you still will spend a LOT of time doing the cutting out. Small movements are very tedious as you can't just ignore them, and you really need to pay attention during the roto so that the masks move at the right times and don't wobble.
Since it sounds like there is quite a bit of space between the foreground (band) and background (fight) plates, you might be able to get a really nice composite with green screen - there could be enough space so that the light spill will be minimal, and the foreground and background won't be interacting with each other (as there is space between them so the shadows won't be cast that far back, i am guessing).
You could potentially shoot the fight scene in the real environment, then have a green screen be put up behind the furniture (still in the real environment so lighting and color and stuff are consistent) and shoot the foreground.
If you needed to, you could maybe shoot the greenscreen in a different location (if there wasn't space on set) with consistent lighting and still get a good result.
In my mind, the lack of interaction between the different plates is a BIG help, not to say this will be a piece of cake, but it might be :)
Re: How to place slow motion on top of normal footage? by Roland R. Kahlenberg on Jun 9, 2009 at 1:21:51 pm
Howzabout using a bed with a high headset that will require you to only draw a simple mask to create the alpha from which to screen the background imagery?
Cheers
RoRK
broadcastGEMs - AEPro Volume 02 (Professional Adobe After Effects Project Files - Now Available). Adobe After Effects Training in South East Asia.
Re: How to place slow motion on top of normal footage? by david bogie on Jun 9, 2009 at 2:39:49 pm
The question implies you've never done anything like this before, never.
Assuming your effects and production noobyhood, spend a few hours researching chromakeying and green- and bluescreen production techniques. You must decide on your shooting format and then you must decide how you're going to light this scene, how you will photograph it, and where. You need a studio.
Then experiment. Shoot some test footage and run some test on the keying the effects so you know what you are doing incorrectly and have time to fix it before you commit to the shoot.
Trying to cut corners on proper background color and lighting is something every newby tries. Doing so will only mess you up in post production. Shoot it properly, chromakey footage CANNOT be fixed later. DV generally is not acceptable for chromakeying unless you understand the limitations. Anything less than DV is out of the question. Shooting on HDV has other problems and they are beyond the scope of this forum.
Everything you need to know about preparing and shooting for keying is already widely known and easily available.
