Modding the Kodak Reels 8mm Film Digitizer (Firmware Hack)

[PaulOckenden]

EDIT - see following comment.

Does anyone know what causes the picture to be taken for each frame? Is it mechanical (linked to the frame advance) or optical (perhaps a sensor on the sprocket hole?).

Only I have one film that scans in *really* juddery. It looks OK on the screen while it's scanning, but the video file produced is very juddery, and often shows the line between the frames and sometimes even a bit of the adjacent frame at the top of the video. Like I said, none of this appears on the mini-screen while scanning.

The reason I asked about optical or mechanical shutter triggering is because if I look at the actual film I can see transparent areas around the sprocket holes.

Shame, because this is an important family film, so I'd really like to be able to scan it.

I'm using the latest @Mac84 firmware BTW. I couldn't get the @0dan0 version to work on my machine.

 

[PaulOckenden]

Does anyone know what causes the picture to be taken for each frame? Is it mechanical (linked to the frame advance) or optical (perhaps a sensor on the sprocket hole?).

Only I have one film that scans in *really* juddery. It looks OK on the screen while it's scanning, but the video file produced is very juddery, and often shows the line between the frames and sometimes even a bit of the adjacent frame at the top of the video. Like I said, none of this appears on the mini-screen while scanning.

The reason I asked about optical or mechanical shutter triggering is because if I look at the actual film I can see transparent areas around the sprocket holes.

Shame, because this is an important family film, so I'd really like to be able to scan it.

I'm using the latest @Mac84 firmware BTW. I couldn't get the @0dan0 version to work on my machine.

Scrap that - it's the machine that's broken. Films which scanned perfectly yesterday are now showing this juddering too.

Unless there's an easy fix it'll have to go back for a replacement.

 

[0dan0]

Here is an example of mine during capture. B model v6.8 with a 32GB card. It did the same with 4GB card (just trying anything at this point). I am still willing to hook up a serial reader if I knew what needed to be captured.

Thank you the for video. I think there might be an exposure bias in the non-volatile memory. V6.8 using extra memory locations to store green tint and exposure bias. The firmware assumes these location are zero as initial condition, but what if they weren't. I will work on a variation to test this.

With a serial port it is easy to test. I going to display green tint and ev bias with the histogram in V6.9.

 

[TheElk]

Scrap that - it's the machine that's broken. Films which scanned perfectly yesterday are now showing this juddering too.

Unless there's an easy fix it'll have to go back for a replacement.

I scanned around 1000 films whit @Mac84 s version and some of these films showed jittering too.
I then scanned this film again. if this was not helping, I replaced the glue point at the film start with a new one. If this was not helping either, I changed the selection of the scan window and put it one or two pictures up or down ... Now I have all films with nearly no jittering. But I wait for the newst version from @0dan0 with no jittering and the correct color grading and the correct brightness.

 

[PaulOckenden]

I scanned around 1000 films whit @Mac84 s version and some of these films showed jittering too.
I then scanned this film again. if this was not helping, I replaced the glue point at the film start with a new one. If this was not helping either, I changed the selection of the scan window and put it one or two pictures up or down ... Now I have all films with nearly no jittering. But I wait for the newst version from @0dan0 with no jittering and the correct color grading and the correct brightness.

Mine is definitely a fault. About half way through a film it started juddering, and then subsequently any film I scanned (including those which had previously scanned perfectly) juddered badly too.
Something has obviously come adrift inside the machine. Luckily it’s fairly new so I can just exchange it, if it was a bit older I’d have pulled it apart to see if I could fix it.

 

[Asielus]

So this only happens on 400 foot reels? I'm not sure I have any of those. Making sure this is play length, not scanning time (Reels scanning time.) As at 15m 10s playback, this error occurs after 2h6m hours of scanning?

It is play length!

 

[0dan0]

This is an experimental V6.9 for Type B only, just to user with the darkening image.

I might fix the issue, and/or it displaying some of the white balance and exposure settings to help debug it.

 

[TheElk]

View attachment 23765
View attachment 23768
This is an experimental V6.9 for Type B only, just to user with the darkening image.

I might fix the issue, and/or it displaying some of the white balance and exposure settings to help debug it.

I scanned my testfilm with Version 6.9 and filmed it whit my mobile. I took only the part from starting the scan to the frame 14.. The Exp stayed at 2618 for the following frames White Bal 2.0 Sharpness -1.5 tint 0. V6.9 produces better scannings, I would say the result on the display during capture is OK and is not showing the darkening, but the result in the file is only slightly better. See attached pictures.
Attached the copy of frame with V6.8 and V6.9

 

[0dan0]

There some confusing element to you images:

Where is this dithering coming from? Was this saved as a GIF, before shared as a PNG.

The image is all posturized.

My scans:

Need to make sure there isn't a hardware issue. You can also do a 50-60 frame scan and share that .MP4.

The white level is tad low, yes, also still too green. White is 192,220,188, so red-blue balance is okay.

While this seems to be blue tinted film, as you are setting Red at 448 (448/256 = 1.75 gain), you might want to back that off a bit, say WB 1.5. But the green gain of 288 is also too much. Those three RGB peaks should line up more.

This exposure is based on luminance, which 70% green. So too much green gain (relative to other color), will decrease exposure.

As someone who wants to have non-clipped images, this is close to a good exposure (very correctable.) But I agree it up to one stop under exposed. v6.9 disabled the EV bias code, as that went haywire on your device. We need to determine if there is something different on your hardware causing the posterization.

 

[TheElk]

There some confusing element to you images:
View attachment 23777
Where is this dithering coming from? Was this saved as a GIF, before shared as a PNG.

View attachment 23780

The image is all posturized.

My scans:
View attachment 23781

Need to make sure there isn't a hardware issue. You can also do a 50-60 frame scan and share that .MP4.


View attachment 23778
The white level is tad low, yes, also still too green. White is 192,220,188, so red-blue balance is okay.

View attachment 23779
While this seems to be blue tinted film, as you are setting Red at 448 (448/256 = 1.75 gain), you might want to back that off a bit, say WB 1.5. But the green gain of 288 is also too much. Those three RGB peaks should line up more.

This exposure is based on luminance, which 70% green. So too much green gain (relative to other color), will decrease exposure.

As someone who wants to have non-clipped images, this is close to a good exposure (very correctable.) But I agree it up to one stop under exposed. v6.9 disabled the EV bias code, as that went haywire on your device. We need to determine if there is something different on your hardware causing the posterization.

The "confusing element" is an ashtray in an oval form.
The pictures I attached are only to see the differences, but I use them to modify between 20fps ( in the past ) and 18 or 24fps for normal work with sound.
All films I had reworked seem to be OK, that means I do not have a problem with the pictures. They are produced with
ffmpeg.exe -loglevel fatal -i "K:\Filme S8\%B%\%1.MP4" -q:v 1 "K:\Filme S8\%B%\PNG\PNG_%1\%1_%%05d.png"

The scanning was this morning without recalibrate the green, thats true. In the meantime I Changed it to better fit. I will scan a new version, see attached picture. I believe green is OK now.

 

[0dan0]

ffmpeg should not be introducing posterization, so very interested in seeing a sample video.

The waveform looks good

and the exposure looks correct based on that histogram. Yes it is darker that stock firmware, but the stock firmware wanted to make everything bright, even if it clipped the results.

 

[TheElk]

ffmpeg should not be introducing posterization, so very interested in seeing a sample video.

The waveform looks good
View attachment 23786
and the exposure looks correct based on that histogram. Yes it is darker that stock firmware, but the stock firmware wanted to make everything bright, even if it clipped the results.

What do you mean with "so very interested in seeing a sample video." I can here only put around 20 MB. I have no youtube account.
Your version V6.9 makes the video brighter than V6.8, but not like @Mac84 s and not as bright as my projection with my original filmprojector.

 

[0dan0]

What do you mean with "so very interested in seeing a sample video." I can here only put around 20 MB. I have no youtube account.
Your version V6.9 makes the video brighter than V6.8, but not like @Mac84 s and not as bright as my projection with my original filmprojector.

Just the 50-60 frames of an original MP4. Something is wrong with the sample frames you have shared, I'm interested in learning what that is. It might be the way images are processed on this forum. Anyway video data via Dropbox, Google drive, Vimeo, even here (under 20MB), use anything that doesn't modify the data (youtube would here.)

The Mac84 firmware has only increased bit-rate, but is stock exposure logic, which often overexposes. If you see regions of white at 255,255,255, you have lost information. Projectors can't overexpose, as there is no digital clipping, pure analog. Film is traditionally very good a preserving highlights, the default Reels scanner was not. These firmware hacks are about undoing many of the wrong things done by dashcam logic (the tech this is based on), improving the dynamic range and color for film scans. The new exposure logic is trying to keep the darkest and lightest scene elements within the limited 0 to 255 range, supported by this 8-bit scanner.

 

[TheElk]

Just the 50-60 frames of an original MP4. Something is wrong with the sample frames you have shared, I'm interested in learning what that is. It might be the way images are processed on this forum. Anyway video data via Dropbox, Google drive, Vimeo, even here (under 20MB), use anything that doesn't modify the data (youtube would here.)

The Mac84 firmware has only increased bit-rate, but is stock exposure logic, which often overexposes. If you see regions of white at 255,255,255, you have lost information. Projectors can't overexpose, as there is no digital clipping, pure analog. Film is traditionally very good a preserving highlights, the default Reels scanner was not. These firmware hacks are about undoing many of the wrong things done by dashcam logic (the tech this is based on), improving the dynamic range and color for film scans. The new exposure logic is trying to keep the darkest and lightest scene elements within the limited 0 to 255 range, supported by this 8-bit scanner.

So. That are 5 takes from the original scan coming from Reels and V69 cutted in Vegas, no correction of anything.
Normally I produce a new mp4 with ffmpeg from the PNG files for resizing 18 fps or 24fps with the following command
ffmpeg.exe -loglevel fatal -framerate 18 -i "%C:~1,-1%_%%05d.png" -vf format=yuv420p -q:v 1 -b:v 29000k "K:\Filme S8\%B%\%1_Dan18fps.mp4"
and I notice a slightly darker and with fewer contrasts version, but I can correct this using Vegas.

 

[0dan0]

Vegas is modify the image, these are frame blended, extra compressed, and changed to 25fps. I only want scanner originals.

Try:

ffmpeg -i input.mp4 -ss 5 -to 8 -c copy output.mp4

This should losslessly extract a few seconds.

 

[TheElk]

Vegas is modify the image, these are frame blended, extra compressed, and changed to 25fps. I only want scanner originals.

Try:


This should losslessly extract a few seconds.

Here they are