Saving as 16bit TIFF

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TheDocAUS
Posts: 50
Joined: 09.12.2016 14:00

Saving as 16bit TIFF

Post by TheDocAUS »

Is there way to save a stack as a16 bit TIFF? I prefer to do post in 16 bit and then convert to 8 bit. I cannot find a setting. My other stacking program can save in 16 bit.
BobStone
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Joined: 03.06.2017 10:13

Re: Saving as 16bit TIFF

Post by BobStone »

Not sure what your source images are, but in In RAW-to-DNG mode, the stack can be saved as a TIFF which will have 16 bits/channel.
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TheDocAUS
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Re: Saving as 16bit TIFF

Post by TheDocAUS »

Frames from a 6K video, so I cannot use the RAW in DNG out function.
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Catherine
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Re: Saving as 16bit TIFF

Post by Catherine »

If the source has more than 8 bits per channel, the resulting TIFF will be 16-bit. If the source is 8 bit or less, the result is 8-bit. Video frames have no more than 8-bits (more is not impossible, but you will be hard-pressed to find such a video file right now).
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TheDocAUS
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Re: Saving as 16bit TIFF

Post by TheDocAUS »

Thanks.
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umbel
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Re: Saving as 16bit TIFF

Post by umbel »

I just wanted to say I would also like to have this feature, particularly for handling highlight brightness expansion with pyramids. Panasonic's November 19th firmware release added 10 bit 4k 30p to the G9 (https://www.panasonic.com/global/consumer/lumix/g9_firmware.html) so, if you're like @TheDocAUS and have a G9, 10 bit video's now much easier to come by. It's also a bit of an odd design choice that an 8 bit source blocks user access to Helicon's internal 16 bit computations (https://www.heliconsoft.com/features/). From what I know of the SSE, AVX2, and AVX-512 instruction sets I presume the stack output lands in a 16 bit array in memory and is reduced to 8 bit when saving. So it feels weird we can't put the 16 bit version of the data on disk if we want.

I think there's a workaround for this in converting video frames to 16 bit oneself ("C:\Program Files\Helicon Software\Helicon Focus 7\ffmpeg\ffmpeg.exe" -i "stack.mp4" -pix_fmt rgb48 stack%03d.tif) rather than relying on Helicon's internal 8 bit request.
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Catherine
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Re: Saving as 16bit TIFF

Post by Catherine »

Thanks for bringing this up, we'll have to make adjustment to how we unpack videos into individual frames as to prevent dynamic range loss for videos with more than 8 bits per pixel.
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