91 lines
4.7 KiB
TeX
91 lines
4.7 KiB
TeX
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% Formats.tex
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% Blackmagic Libre
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% Copyright (C) 2023, Jeff Moe
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% This document is licensed under the Creative Commons Attribution 4.0
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% International Public License (CC BY-SA 4.0) by Jeff Moe.
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%
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\section{Formats and Codecs Used by Blackmagic}
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\label{sec:overview-formats}
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\index{formats}\index{codecs}
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An overview of the formats used by Blackmagic.
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\section{Video Samples}
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Video samples of every format and codec combination from the
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Cinema 6K are available here:
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\url{https://spacecruft.org/spacecruft/blackmagic-libre-data}
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\section{LUT}
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Film to Video LUT, etc.
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Dynamic range.
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{description}
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\item [Ext Video]
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\item [Video]
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\item [Film]
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\end{description}
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\end{mdframed}
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\section{CinemaDNG}
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Notes.
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So CinemaDNG is the "open" HDR-like video format. Blackmagic was using it in their earlier cameras.(edited)
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But they got a patent threat, so switched to their proprietary .braw, and removed support for CinemaDNG.
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Patent threat may have come from "Red" (camera brand).
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Or maybe Adobe.
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So if you want to take a "HDR"-like photo with a DSLR, you take a picture "normal", then down a step, then up a step, for example.
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But this means there can be movement between the shots, even if the camera is programmed to take the shots quickly.
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With the Blackmagic internal hardware, all steps (13 of them in fact) are all taken in one shot.
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Their old cameras with that feature + CinemaDNG could be a good combo.
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Not sure if kdenlive etc can do CinenaDNG though.
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Taking a pic with 13 steps all in one shot. wowza, that's pretty cool.
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So later, you can just go in post processing and set light how you want, it is very detailed, etc. It would pixelize dark areas that are brightened, or example.
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\section{Unorganized Notes}
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\begin{description}
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\item Blackmagic BRAW (somemovie.braw) format is proprietary.
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\item There is a Linux player, but you need their proprietary SDK, with registration required.
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\item The camera can do a .mov format, which linux can read.
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\item But that doesn't do the max pixel sizes (6k).
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\item I think the BRAW format is a video HDR format (e.g. takes each photo at multiple exposures).
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\item The raw still images can't be read by gimp or darktable, but rawtherapee can read them.
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\item There is one crappy ffmpeg implementation for braw, but not maintained, doesnt really work.
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\item The 4k .mov works ok.
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\item Video .mov on device at 4k looks good played with mpv. But something is a bit off with colorspace, it is like looking thru an ND filter.
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\item Like Blackmagic RAW (.braw) doesn't work by default in debian, but the ProRes (.mov) does.
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\item I can get HDMI out working. I can get 4K video recording to SD working with libre software.
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\item Not working: 6K, due to it only recording to their proprietary format.
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\item Not working: HDR (multi exposure per frame), due to it only recording to their proprietary format, afact.
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\item Definitely not libre stuff.
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\item But one of their formats is .mov, which ffmpeg, etc can read.
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\item Their other format is .braw, their proprietary raw, which can't really be read libre.
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\item One feature is interlacing of frames with different exposure levels.
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\item So "in software"/postprocessing you can set exposure values with far more control.
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\item And just better detail overall.
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\item Canon has HDR still photo built into the camera. Or on other cameras you can just do 3 (or whatever) then use software such as darkdable to make the final image.
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\item The Blackmagic has HDR Still Image, .dng, that rawtherapee can read, but nothng else i tried can.(edited)
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\item For use with a libre toolchain, the older generation to the 6K series is better for recording video.
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\item Because it can do the CinemaDNG that in theory can by read with free software.
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\item Even their cams that at 10+ years old are still quite good, if the hunt isn't for megapixels, but image quality.
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\item The v2 series cameras all appear to use the newer proprietary Blackmagic RAW format.
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\item The DNG files, both the CinemaDNG and supposedly the braw files, are series of tiff files, or similar. This is how ffmpeg handles them, afaict.
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\item The sensor on the Blackmagic can take multiple exposures in a single shot.
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\item This makes for a better picture with more detail, better in dark areas, etc. in general.
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\item With the .braw format and the proprietary app that reads it, you can access all of these layers.
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\item So, for instance, if one part is too blown out, you can select that area and get a darker version of it, as taken by the camera, not kludge later with an algorithm. So the picture is much better.
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\item With kdenlive, iit can only read the .mov format of Blackmagic. So there is no way to access these other exposure layers.
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\end{description}
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