Hello all,
I'm new here, but this is a nagging old problem for many of us that work with film, or with film converted to video. I know about film scanning systems that capture frame-by-frame, but the system I'm working with operates in real time. The film runs at (round numbers) 20 fps with a 3-blade shutter, so there are 60 images per second. (The film advances every third time the shutter opens. This is how just about all film projectors work, though the number of shutter blades and frame rates obviously vary.) On the video camera side, I'm capturing 60p.
Just as a quick but relevant aside, my previous system was standard def, so it captured 60 FIELDS per second, interlaced into 30 FRAMES per second. The result was that typically every 3rd frame was a blend of 2 different film frames due to interlacing. The blending was mostly only noticeable with close-up hand-held camera movement. (Even Hollywood releases sometimes have frame blending, though it occurs every 5th frame due to the 24fps frame rate of the film with a 5-blade shutter)
So switching to the 60p camera system--which matches the 60/second film playback shutter--should have solved the blending issue right? Well not quite. It helped for sure. Each film frame is now represented as 3 video frames, as theory would predict, except that the third frame is sometimes blended. Because there isn't perfect synchronization between camera and telecine projector, a phasing occurs that gradually run in and out of perfect 1-to-3 film to video frame ratio. So for example video frames 1, 2, and 3 represent film frame 1; video frames 4, 5, and 6 represent film frame 2, and so on for several seconds until, say at video frames 91, 92, and 93--which should represent film frame 31--video frame 93 is also showing a ghost image of film frame 32--a blend of frames 31 and 32. (Or if the projector was running slower than the camera, video frame 91 would start to show a blend with film frame 30 still in the gate before the shutter closed, advanced, and displayed frame 31)
Using a higher shutter speed on the video camera would seem to alleviate this problem. However, the shutter speed must be a sufficient duration to span the entire period of the shutter cycle so as not to introduce another phasing problem--that of periodic brightening and darkening of the video.
So long story short I've done about everything I can to get the best results possible with the hardware of this system, and the results are impressive as is. But I wish to take this further if possible. I am also familiar with Avisynth and the very advanced filters and techniques that it promises. There is a plugin for AviSynth called SRestore that in theory as I understand should be able to compare all of my video frames and detect which ones are blended. Then it replaces that frame with whichever contributing frame is the stronger of the two. This would be ideal for the situation I describe because it would account for the dynamics of the phase mismatch.
The problem is that even with some help I have yet to get AviSynth working. There are missing dll files to install so that Virtualdubmod can install so you can run avisynth, then you have to install several plugins, then write or modify scripts. Then trial and error if it even works, and if not go to the doom9 forum. Really?? Isn't there anything else out there that can do this? Anything with a GUI so that you don't have to be a programmer just to do this fairly simple and common problem?? Or are there any AviSynth experts out there that could consult and set up a simple workflow for me??
Any insights, ideas, advice, or observations would be most welcome. Thank you all.
I'm new here, but this is a nagging old problem for many of us that work with film, or with film converted to video. I know about film scanning systems that capture frame-by-frame, but the system I'm working with operates in real time. The film runs at (round numbers) 20 fps with a 3-blade shutter, so there are 60 images per second. (The film advances every third time the shutter opens. This is how just about all film projectors work, though the number of shutter blades and frame rates obviously vary.) On the video camera side, I'm capturing 60p.
Just as a quick but relevant aside, my previous system was standard def, so it captured 60 FIELDS per second, interlaced into 30 FRAMES per second. The result was that typically every 3rd frame was a blend of 2 different film frames due to interlacing. The blending was mostly only noticeable with close-up hand-held camera movement. (Even Hollywood releases sometimes have frame blending, though it occurs every 5th frame due to the 24fps frame rate of the film with a 5-blade shutter)
So switching to the 60p camera system--which matches the 60/second film playback shutter--should have solved the blending issue right? Well not quite. It helped for sure. Each film frame is now represented as 3 video frames, as theory would predict, except that the third frame is sometimes blended. Because there isn't perfect synchronization between camera and telecine projector, a phasing occurs that gradually run in and out of perfect 1-to-3 film to video frame ratio. So for example video frames 1, 2, and 3 represent film frame 1; video frames 4, 5, and 6 represent film frame 2, and so on for several seconds until, say at video frames 91, 92, and 93--which should represent film frame 31--video frame 93 is also showing a ghost image of film frame 32--a blend of frames 31 and 32. (Or if the projector was running slower than the camera, video frame 91 would start to show a blend with film frame 30 still in the gate before the shutter closed, advanced, and displayed frame 31)
Using a higher shutter speed on the video camera would seem to alleviate this problem. However, the shutter speed must be a sufficient duration to span the entire period of the shutter cycle so as not to introduce another phasing problem--that of periodic brightening and darkening of the video.
So long story short I've done about everything I can to get the best results possible with the hardware of this system, and the results are impressive as is. But I wish to take this further if possible. I am also familiar with Avisynth and the very advanced filters and techniques that it promises. There is a plugin for AviSynth called SRestore that in theory as I understand should be able to compare all of my video frames and detect which ones are blended. Then it replaces that frame with whichever contributing frame is the stronger of the two. This would be ideal for the situation I describe because it would account for the dynamics of the phase mismatch.
The problem is that even with some help I have yet to get AviSynth working. There are missing dll files to install so that Virtualdubmod can install so you can run avisynth, then you have to install several plugins, then write or modify scripts. Then trial and error if it even works, and if not go to the doom9 forum. Really?? Isn't there anything else out there that can do this? Anything with a GUI so that you don't have to be a programmer just to do this fairly simple and common problem?? Or are there any AviSynth experts out there that could consult and set up a simple workflow for me??
Any insights, ideas, advice, or observations would be most welcome. Thank you all.