Strange single frame glitch on footage

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edshiers

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Strange single frame glitch on footage

PostFri May 07, 2021 8:11 pm

Hello all, I'm new to Black Magic and have just bought the BMPCC 6K PRO.
I just shot my first piece on it and on a single frame, right in the middle of a long take I noticed an odd glitch/corruption on the image.
Im shooting:
B raw
constant bitrate
5:1
6k 6144x3456
23.98fps
Media: SAMSUNG T5 2TB SSD

I'm using Adobe Premiere with the BM Raw 2.0

Has any one encountered this before, know what it is and/or have any suggestions for avoiding this happen?

Thanks in advance!
Attachments
glitch1.jpg
Here's a screenshot of the issue - Im talking about the blue line toward the bottom of picture. Not the grey bar.
glitch1.jpg (246.35 KiB) Viewed 1410 times
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rick.lang

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Re: Strange single frame glitch on footage

PostSat May 08, 2021 1:15 am

Do you still have the clip on your media card to playback in camera in order to determine if the glitch is recorded on the media or later in the workflow?
Rick Lang
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edshiers

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Re: Strange single frame glitch on footage

PostSat May 08, 2021 2:16 am

rick.lang wrote:Do you still have the clip on your media card to playback in camera in order to determine if the glitch is recorded on the media or later in the workflow?



The glitches were not on the original media.


Bizarrely, the glitch has now disappeared. I was able to export the clip with the glitch on it - so it's wasn't a preview issue.
I since found a second glitch on a different clip - this one yellow. Same thing in a different location in the frame - now THIS one has also since disappeared. I had tried restarting my mac and premiere, and that didn't fix it. But now a few hours later it's gone on it's own accord. So it's a weird temporary thing that I don't seem able to remove on my own but which goes on it's own a few hours later.
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antoine

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Re: Strange single frame glitch on footage

PostSat May 08, 2021 9:05 am

Could you share the .braw ? We would like to see if this also happens with our plugin
BRAW Studio FREE and Premium for Adobe Premiere Pro and After Effects, with a brand new Desktop .BRAW Player and Color Grader, as well as an automatic White Balance Color Picker tool
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edshiers

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Re: Strange single frame glitch on footage

PostSat May 08, 2021 11:58 pm

antoine wrote:Could you share the .braw ? We would like to see if this also happens with our plugin

Can I send it privately?
Sorry - it's just that it's something I shot for a business
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Ric Murray

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Re: Strange single frame glitch on footage

PostMon May 10, 2021 8:46 pm

Which model Mac are you using? The trashcans with their under-powered, under cooled graphics cards often did this at odd intervals when over heated during a render out. The work around is to set the render frame rate lower (do not use "auto").
Creativity is the ability to accept ambiguity.
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antoine

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Re: Strange single frame glitch on footage

PostTue May 11, 2021 6:19 am

edshiers wrote:
antoine wrote:Could you share the .braw ? We would like to see if this also happens with our plugin

Can I send it privately?
Sorry - it's just that it's something I shot for a business


That would be great ! By PM or https://www.autokroma.com/contact

Thanks
BRAW Studio FREE and Premium for Adobe Premiere Pro and After Effects, with a brand new Desktop .BRAW Player and Color Grader, as well as an automatic White Balance Color Picker tool
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edshiers

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Re: Strange single frame glitch on footage

PostThu May 13, 2021 8:24 pm

Ric Murray wrote:Which model Mac are you using? The trashcans with their under-powered, under cooled graphics cards often did this at odd intervals when over heated during a render out. The work around is to set the render frame rate lower (do not use "auto").



Im using an Mac (Retina 5K, 27-inch, 2019)
3.6 GHz 8-Core Intel Core i9
128 GB 2667 MHz DDR4
Radeon Pro Vega 48 8 GB

Big Sur

And I'm not rendering anything - this is just normal playback. And the computer was running cool. And it's also weird that both glitches have dissapeared now, even though I was able to render out one of them (so not just a preview issue)

Very odd. Im scared to shoot in RAW after this
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rick.lang

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Re: Strange single frame glitch on footage

PostThu May 13, 2021 9:51 pm

Ed, you might do more tests over time to see if that glitch returns or was just a strange one-time blip in the multiverse. Don’t let one frame in one clip determine your future. Caution is good, but win back your confidence.
Rick Lang
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smunaut

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Re: Strange single frame glitch on footage

PostFri May 14, 2021 11:07 am

It's a fallacy that hard drives and SSD store data without error ... all media have a silent/undetected read error rate (either due to media itself or the transport). It's insanely tiny but it's there and when dealing with hundred of Gigabytes of footage, a single bit flip might result in some visual corruption.

That's why it's good to compute checksums reading from the original media/drive. Then disconnect it, reconnect it (to avoid caching), make the copy and then recompute checksums from the copy and make sure they match.
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