is there a way to adjust underexposed footage?

[marcorocchini]

Hi

and however the cats.



however I have this DJI_0002.MP4 footage, underexposed, wrong shot, wrong color, all wrong.

https://www.swisstransfer.com/d/3af0f130-1d7b-4919-85c6-a107758dc975

I wonder if is there a way to "adjust" exposure/color/levels of the entire clip with a dynamic adjustment if as possible and in the limits of a postprocessing, keep as reference considering levels/color of another camera in the same interview, this:

https://www.swisstransfer.com/d/93ab278e-765c-4682-ad98-7aed55133981



thanks

[_Al_]

I think you have a solid videoeditor now, not sure which one. You can do a fast fix using curves.

[Alwyn]

1.5gb is a big file to download. I suggest you trim in down (eg with AVIDemux); people are more likely to look at it then. In AVIDemux, trim it with the A and B buttons then save it with Video Output>Copy Audio Output>Copy then Output Format>MP4 Muxer.

[jagabo]

Something like:

ColorYUV(off_y=5).ConvertToRGB(matrix="rec709").RGBAdjust(r=2.5, g=2.5, b=2.5, rg=1.3, gg=1.3, bg=1.3).ConvertToYV12(matrix="rec709")

The sky is blown out though.


[Attachment 68167 - Click to enlarge]

[Alwyn]

Virtual Dub 2 with the Colormill filter. Mid levels boosted to 100, low up 25, high up 10, with a slight increase in saturation (up 13).


[Attachment 68159 - Click to enlarge]

[Sharc]

Try Retinex or autoadjust (less flicker) for dynamic adjustments (just a quickshot, not optimzed)

[Attachment 68161 - Click to enlarge]

[rgr]

--

[rgr]

Original:

[Alwyn]

@Sharc, what's Retinox and how do you use it?

@RGR, pointless if you don't tell us how you did it with what.

[Sharc]

@Sharc, what's Retinox and how do you use it?

https://github.com/Asd-g/AviSynth-Retinex

You find it also in Selur's Hybrid under Vapoursynth filters (I didn't find it under Avisynth)

[Alwyn]

@Sharc, thanks for that. I googled it and it sounded like spooky stuff.

[jagabo]

I just noticed that later in the clip the sun comes out and it gets brighter. Some further adjustments are required for that.

[Sharc]

Here a less aggressive Retinex setting which includes the changing sunlight scene

[marcorocchini]

[Attachment 68172 - Click to enlarge]

oh my

[marcorocchini]

thanks, but the super mysterious retinex how have to be used?

FFVideoSource("C:\Users\Administrator\Desktop\DJI_0002.MP4")

converttoYV24()
#MSRCP(fulls=false,fulld=true,lower_thr=0.9,upper_thr=0.1,chroma_protect=1)

MSRCP(sigma=[300,300,300], lower_thr=0.001, upper_thr=0.001, fulls=false, fulld=True, chroma_protect=1)

converttoYUY2()

Prefetch(8)

I try casual settings after download and locate the .dll on the avisynth folder


[Attachment 68173 - Click to enlarge]

but how to use it?

[davexnet]

Are they the original camera files?

[Sharc]

thanks, but the super mysterious retinex how have to be used?

converttoYV24(matrix="Rec709")
MSRCP(sigma=2000,fulls=false,fulld=false,lower_thr=0.0001,upper_thr=0.0001,chroma_protect=2)
converttoYV16(matrix="Rec709")

or

smoothtweak(Brightness=4)
converttoPlanarRGB(matrix="Rec709")
MSRCR(sigma=500,fulls=false,fulld=true,lower_thr=0.0001,upper_thr=0.0001)
converttoYV16(matrix="Rec709")

I am using the 32bit retinex.dll in the AviSynth+ plugins folder

The attached Retinex_3.mp4 is an example for the 2nd code above. The colors are more saturated.

[jagabo]

Here's mt_lut() with a quarter wave sinusoidal adjustment, plus a little gamma and saturation with ColorYUV(). Frame 9000:


[Attachment 68179 - Click to enlarge]

A little like _Al_'s curve in post #2.

[rgr]

@RGR, pointless if you don't tell us how you did it with what.

It doesn't matter if it's not good enough. Vegas: brightness and contrast only. I will not give more, because I did not save, and the computer has restarted.

[_Al_]

retinex might be ok, but most often it gives weird results, perhaps it needs to be tweaked a lot to come up with a good result, tried Sharc's lines (though in Vapoursynth) and it did not look good, not sure what was going on:

yuv444 = clip.resize.Bicubic(format =vs.YUV444P16)
fixed = core.retinex.MSRCP(yuv444,lower_thr=0.0001, upper_thr=0.0001, fulls=False, fulld=True, chroma_protect=2)

but if using videoeditor it really could be beneficial even if batch fixing files later for some reason, because in videoeditor one can come up really quickly with a color grading fix, then exporting a cube LUT (like in Magix Vegas) and then using Vapoursynth and a encoder for some batch re-encoding. Though if using a videoeditor those LUTs can be imported as well so rather not using external encoder as well.
If for some reason batch re-encoding is needed, using available LUT (from Vegas) , using vapoursynth:

clip = core.lsmas.LibavSMASHSource(r'DJI_0002.MP4')
rgb_float = core.resize.Bicubic(clip, format = vs.RGBS, matrix_in_s='709')
rgb_float = core.timecube.Cube(rgb_float, r"underexposed_event.cube") #https://github.com/sekrit-twc/timecube/releases
clip_lut_applied = core.resize.Bicubic(rgb_float, format=vs.YUV420P8, matrix_s='709')

that LUT was made in Magix Vegas using color grading using curves, bringing darks down using levels, also saturation tiny bit up

[jagabo]

Here's something very simple that doesn't require any third party filters:

Overlay(last, last.ColorYUV(gamma_y=500), opacity=0.7)
ColorYUV(gain_y=110, off_y=-80)

[Attachment 68192 - Click to enlarge]

The first line blends the original video with a gamma adjusted version. You can change the opacity to get more or less of the gamma adjusted values. ColorYUV on the second line is used to adjust the black and white levels.

[lordsmurf]

HDR filters probably do this.
Premiere, Avid, FCP, etc. All of them, even many basic softwares.

[Sharc]

retinex might be ok, but most often it gives weird results, perhaps it needs to be tweaked a lot to come up with a good result, tried Sharc's lines (though in Vapoursynth) and it did not look good, not sure what was going on:

yuv444 = clip.resize.Bicubic(format =vs.YUV444P16)
fixed = core.retinex.MSRCP(yuv444,lower_thr=0.0001, upper_thr=0.0001, fulls=False, fulld=True, chroma_protect=2)

I have no experience with the Vapoursynth variant of Retinex, but it looks like you missed the variable 'sigma' (the default isn't very suitable for this clip), and the boolean 'fulld' should be false for the YUV format as I understand.
Filters like Retinex and AutoAdjust have their quirks (e.g. flicker) as they are attempts to make adjustments dynamically according to the prevailing scene, as opposed to a static optimizations which may fix a certain scene but may fall off when the conditions change. A mask based on luma can further help to improve the result of the auto-correcting tools. Requires more experimentation though.

Edit:
I just noticed that the retinex output depends on the resolution of the frame. For my former SBS comparisons I reduced the frame size of the source before applying the filter. For the original resolution one would have to adjust the settings (boost the sigma) it seems, for MSRCR something like

smoothtweak(brightness=4,saturation=0.6) #adjust the saturation to taste
converttoPlanarRGB(matrix="Rec709")
MSRCR(sigma=3500, fulls=false, fulld=true, lower_thr=0.0001, upper_thr=0.0001)
converttoYV16(matrix="Rec709") #or YUY2, YV12

[jagabo]

By the way, if you crop away the bright sky MSRCR makes both the darker and lighter frames look about the same.

[Sharc]

By the way, if you crop away the bright sky MSRCR makes both the darker and lighter frames look about the same.

Probably a similar effect will happen when (luma-) masking certain parts of the image.

Edit: ..... however for more obvious reasons, as the masked part will not be tweaked the same.
If one prefers to leave the sky untouched and only tweak the rest, one could use for example:

lumamask=clip.mt_binarize(threshold=80,upper=true).converttoYV12(matrix="Rec709").GaussianBlur(varY=2000.0)    # build a luma mask
overlay(clip, clip.smoothtweak(brightness=4, saturation=0.6).converttoPlanarRGB(Matrix="Rec709").MSRCR(sigma=3500,fulls=false,fulld=true,lower_thr=0.0001,upper_thr=0.0001), mask=lumamask)
converttoYV16(matrix="Rec709") #or YUY2, YV12

Here the same as Retinex_4 above, but preserving the original sky colors. Can be helpful for backlight shots.