Doom9's Forum - View Single Post - How do I speed up AviSynth processing a VideoFred script?

johnmeyer · 7th September 2020, 16:56

I've posted about five versions of the script, all of them in VideoFred's threads. This is the latest one:

John Meyer's Branch of VideoFred's Fim Restoration Script Including GamMac

I would strongly recommend that you try to get this working by setting Result to either 4 or S4 (the latter gives you a before/after look at the film). Do NOT use GamMac initially because it slows things down.

Stability can be an issue. I have not tested this with 4K scans and I suspect that you are going to have problems with crashes. This isn't caused by my script, or VideoFred's script, but has to do with AVISynth and its memory management. You will also have to play around a lot with all the parameters of the "newer" AVISynth+ multi-threading model. I recently upgraded my CPU to a 6-core, 12-thread model and even with that, I usually have to keep the thread count down to 4-6 in order to keep it stable. Also, I turn off multi-threading when I am scrubbing back and forth, while figuring out the best settings for each reel, and then only turn on the multi-threading when I actually create the final output. Lower resolution will reduce or eliminate the stability issues and will dramatically decrease the time it takes to get through your project.

So, I strongly recommend that you capture at lower resolution, or that you downscale prior to doing restoration. 8mm and Super 8 really don't need much more than 720x480 to capture all the detail. I capture with an HD camcorder at 1440x1080, but then have the camera downscale to SD as it outputs to my computer.

I do this for 16mm as well, although with that larger gauge you can sometimes get more detail with HD (1920x1080) resolution.

You certainly don't need to use 4K resolution for 8mm or Super 8 home movies and probably not 16mm as well.

I had a chance to prove this with some 16mm B&W film I transferred for a client that was taken in 1935 of the Nazis in Dresden, Germany. The man taking it owned a movie camera factory and knew how to use his equipment, so the film was sharp, steady, correctly exposed and properly developed. I transferred all the film and we donated the results to the Wiesenthal Museum in L.A. Years later, the Smithsonian Channel found it and wanted to use it. However, they wanted to have the film re-scanned by their lab in L.A. I arranged for the film to be sent there, scanned, and then had the lab send the digital files to me, so I could review the results prior to sending them to the production company.

This gave me a chance to compare my transfers, done on a modified Eiki 16mm projector to a camcorder mounted at point blank range capturing the image prior to the focal point (i.e., upside down).

What I found was exactly what I expected: their scans (done on a $100,000 Spirit) did a better job of extracting shadow details (which your capture device should do as well since you can adjust the gamma) but I saw no evidence of new detail revealed in the normally-exposed sections of each frame, nor did I sense any additional sharpness (i.e., the illusion of more detail by having sharper edges).

So, I recommend that you spend some time doing transfers at lower resolution, or simply down-resn'g some clips from material you've already transferred, and see if you can detect any loss of detail. With 8mm, there is no way you'll be able to see any difference. That tiny little piece of celluloid simply cannot store that much detail.

7th September 2020, 16:56	#7 \| Link
johnmeyer Registered User Join Date: Feb 2002 Location: California Posts: 2,695	I've posted about five versions of the script, all of them in VideoFred's threads. This is the latest one: John Meyer's Branch of VideoFred's Fim Restoration Script Including GamMac I would strongly recommend that you try to get this working by setting Result to either 4 or S4 (the latter gives you a before/after look at the film). Do NOT use GamMac initially because it slows things down. Stability can be an issue. I have not tested this with 4K scans and I suspect that you are going to have problems with crashes. This isn't caused by my script, or VideoFred's script, but has to do with AVISynth and its memory management. You will also have to play around a lot with all the parameters of the "newer" AVISynth+ multi-threading model. I recently upgraded my CPU to a 6-core, 12-thread model and even with that, I usually have to keep the thread count down to 4-6 in order to keep it stable. Also, I turn off multi-threading when I am scrubbing back and forth, while figuring out the best settings for each reel, and then only turn on the multi-threading when I actually create the final output. Lower resolution will reduce or eliminate the stability issues and will dramatically decrease the time it takes to get through your project. So, I strongly recommend that you capture at lower resolution, or that you downscale prior to doing restoration. 8mm and Super 8 really don't need much more than 720x480 to capture all the detail. I capture with an HD camcorder at 1440x1080, but then have the camera downscale to SD as it outputs to my computer. I do this for 16mm as well, although with that larger gauge you can sometimes get more detail with HD (1920x1080) resolution. You certainly don't need to use 4K resolution for 8mm or Super 8 home movies and probably not 16mm as well. I had a chance to prove this with some 16mm B&W film I transferred for a client that was taken in 1935 of the Nazis in Dresden, Germany. The man taking it owned a movie camera factory and knew how to use his equipment, so the film was sharp, steady, correctly exposed and properly developed. I transferred all the film and we donated the results to the Wiesenthal Museum in L.A. Years later, the Smithsonian Channel found it and wanted to use it. However, they wanted to have the film re-scanned by their lab in L.A. I arranged for the film to be sent there, scanned, and then had the lab send the digital files to me, so I could review the results prior to sending them to the production company. This gave me a chance to compare my transfers, done on a modified Eiki 16mm projector to a camcorder mounted at point blank range capturing the image prior to the focal point (i.e., upside down). What I found was exactly what I expected: their scans (done on a $100,000 Spirit) did a better job of extracting shadow details (which your capture device should do as well since you can adjust the gamma) but I saw no evidence of new detail revealed in the normally-exposed sections of each frame, nor did I sense any additional sharpness (i.e., the illusion of more detail by having sharper edges). So, I recommend that you spend some time doing transfers at lower resolution, or simply down-resn'g some clips from material you've already transferred, and see if you can detect any loss of detail. With 8mm, there is no way you'll be able to see any difference. That tiny little piece of celluloid simply cannot store that much detail. Last edited by johnmeyer; 7th September 2020 at 17:09.