Trying to understand colour, try N!
https://blender.stackexchange.com/questions/46825/render-with-a-wider-dynami... well, this one says EXR can hold quite a big value per channel, way above 1.0f, obviously. But for displaying (and encoding?) it must be compressed back to device-specific 0 - 1.0 range. Thing is, if I open exr example file in gimp 2.10 and re-export it - it retain its above 100% values. It does not do this if I do this same roundtrip via cingg. So yea, we seems to be clamping at output. Still not sure where, may be in fader? (where fade can't be more than 100%) . May be its time to ask Lion (Adam).
вт, 7 нояб. 2023 г., 18:13 Andrew Randrianasulu <[email protected]>:
https://blender.stackexchange.com/questions/46825/render-with-a-wider-dynami...
well, this one says EXR can hold quite a big value per channel, way above 1.0f, obviously. But for displaying (and encoding?) it must be compressed back to device-specific 0 - 1.0 range.
Thing is, if I open exr example file in gimp 2.10 and re-export it - it retain its above 100% values. It does not do this if I do this same roundtrip via cingg. So yea, we seems to be clamping at output.
and this article about Premiere tries to explain Scopes, and especially floating point vs 8bit input - Premiere apparently can limit this setting for scopes themselves.... https://blog.frame.io/2017/09/27/introduction-to-video-scopes/ so, HDR as used in ultra HD need some scope that goes to 10.000 (so, logarithmic I guess ...)! something we should write somewhere in TODO, I guess .....
Still not sure where, may be in fader? (where fade can't be more than 100%) . May be its time to ask Lion (Adam).
вт, 7 нояб. 2023 г., 18:32 Andrew Randrianasulu <[email protected]>:
вт, 7 нояб. 2023 г., 18:13 Andrew Randrianasulu <[email protected]>:
https://blender.stackexchange.com/questions/46825/render-with-a-wider-dynami...
well, this one says EXR can hold quite a big value per channel, way above 1.0f, obviously. But for displaying (and encoding?) it must be compressed back to device-specific 0 - 1.0 range.
Thing is, if I open exr example file in gimp 2.10 and re-export it - it retain its above 100% values. It does not do this if I do this same roundtrip via cingg. So yea, we seems to be clamping at output.
and this article about Premiere tries to explain Scopes, and especially floating point vs 8bit input - Premiere apparently can limit this setting for scopes themselves....
https://blog.frame.io/2017/09/27/introduction-to-video-scopes/
so, HDR as used in ultra HD need some scope that goes to 10.000 (so, logarithmic I guess ...)!
something we should write somewhere in TODO, I guess .....
second technique about dealing with too shadowy video: https://larryjordan.com/articles/premiere-pro-two-options-to-control-sdr-vid... ===== *A CREATIVE USE OF BLEND MODES* This tip was suggested by *FoodShipNine*. If all you want to do is control black levels, but let highlights float – which would apply to most web videos – here’s an option. - Using *File > New > Black Video*, create a new video clip. This contains a single color – black – with a video level of 0 IRE. - Place it above all clips in the timeline, similar in concept to an adjustment layer. - Select the black video clip then, in *Effect Controls*, set *Opacity > Blend Mode* to *Lighten*. This sets all pixel grayscale values in all clips below the black video clip to whichever is lighter, the black video clip or the video itself. ====== so, if we does not have this mode we probably should :)
Still not sure where, may be in fader? (where fade can't be more than 100%) . May be its time to ask Lion (Adam).
вт, 7 нояб. 2023 г., 18:47 Andrew Randrianasulu <[email protected]>:
вт, 7 нояб. 2023 г., 18:32 Andrew Randrianasulu <[email protected]>:
вт, 7 нояб. 2023 г., 18:13 Andrew Randrianasulu <[email protected]
:
https://blender.stackexchange.com/questions/46825/render-with-a-wider-dynami...
well, this one says EXR can hold quite a big value per channel, way above 1.0f, obviously. But for displaying (and encoding?) it must be compressed back to device-specific 0 - 1.0 range.
Thing is, if I open exr example file in gimp 2.10 and re-export it - it retain its above 100% values. It does not do this if I do this same roundtrip via cingg. So yea, we seems to be clamping at output.
and this article about Premiere tries to explain Scopes, and especially floating point vs 8bit input - Premiere apparently can limit this setting for scopes themselves....
https://blog.frame.io/2017/09/27/introduction-to-video-scopes/
so, HDR as used in ultra HD need some scope that goes to 10.000 (so, logarithmic I guess ...)!
something we should write somewhere in TODO, I guess .....
second technique about dealing with too shadowy video:
https://larryjordan.com/articles/premiere-pro-two-options-to-control-sdr-vid...
=====
*A CREATIVE USE OF BLEND MODES*
This tip was suggested by *FoodShipNine*.
If all you want to do is control black levels, but let highlights float – which would apply to most web videos – here’s an option.
- Using *File > New > Black Video*, create a new video clip. This contains a single color – black – with a video level of 0 IRE. - Place it above all clips in the timeline, similar in concept to an adjustment layer.
- Select the black video clip then, in *Effect Controls*, set *Opacity
Blend Mode* to *Lighten*. This sets all pixel grayscale values in all clips below the black video clip to whichever is lighter, the black video clip or the video itself.
======
so, if we does not have this mode we probably should :)
https://prolost.com/blog/aces according to this article Tarantino unintentionally got his own color space { I think this is a joke, too uncinema-tic for understanding it } ==== The ACEScc log color space is, in my experience, a creatively-friendly color space for grading. There’s also a tweaked version of it called ACEScct. The T is for “toe,” so this is the profile favored by Quentin Tarantino. ===== this made me stop and laugh! Not sure why .... hopefully all of this can be realized by those cube lookup tables?
Still not sure where, may be in fader? (where fade can't be more than 100%) . May be its time to ask Lion (Adam).
We have Lighten in patchbay --> Overlay --> Logical --> lighten. Thanks for the tip.
вт, 7 нояб. 2023 г., 23:25 Andrea paz <[email protected]>:
Still not sure where, may be in fader? (where fade can't be more than 100%) . May be its time to ask Lion (Adam).
Maybe it is in the code strings where "CLAMP" is?
well, this is macro, so it used to clamp various things, not just colors ......
вт, 7 нояб. 2023 г., 23:33 Andrea paz <[email protected]>:
well, this is macro, so it used to clamp various things, not just colors ......
I had found this string in some plugins. Could it be that it is about colors? CLAMP(output, 0, 1.0);
possible, but try to read roughly code around it... and feel free to experiment with "//" commenting it out :) while I think this will not fix final output clipping ....
and feel free to experiment with "//" commenting it out :)
I tried to compile by commenting out the string CLAMP(output, 0, 1.0) in histogram.C. The compilation occurred without errors. CinGG starts without errors and the Histogram plugin runs without errors. In the graph you can see that the data in the area beyond 1.0 is not visible, however, this time the plugin seems to work in float because I was able to pull out the hdr data that was present in the original image. See attached image. Note that the normal plugin has a horizontal line between 100 and 110% (as well as between 0 and -10%). It is the clip line. That line has remained in black but is no longer there in super-white. No errors or other messages are reported in the terminal from which I ran CinGG. I will continue testing, but if all goes well I propose to remove the line from the code because having an important plugin like histogram without the clip is a good thing.
Andrea's results are really interesting. I wonder why the Clamp is there if it is not needed? Will removing it affect existing older projects? On Wed, Nov 8, 2023 at 7:13 AM Andrea paz via Cin < [email protected]> wrote:
and feel free to experiment with "//" commenting it out :)
I tried to compile by commenting out the string CLAMP(output, 0, 1.0) in histogram.C. The compilation occurred without errors. CinGG starts without errors and the Histogram plugin runs without errors. In the graph you can see that the data in the area beyond 1.0 is not visible, however, this time the plugin seems to work in float because I was able to pull out the hdr data that was present in the original image. See attached image. Note that the normal plugin has a horizontal line between 100 and 110% (as well as between 0 and -10%). It is the clip line. That line has remained in black but is no longer there in super-white. No errors or other messages are reported in the terminal from which I ran CinGG. I will continue testing, but if all goes well I propose to remove the line from the code because having an important plugin like histogram without the clip is a good thing. -- Cin mailing list [email protected] https://lists.cinelerra-gg.org/mailman/listinfo/cin
I did further testing by paying attention to the operation of other plugins in the Histogram queue and always monitoring CPU and RAM usage. So far I have not noticed any differences with appimage which does not have the modification. I only have a few old projects involving CC, but they were loaded correctly and I don't seem to notice any differences. No error lines appear on the terminal. PS: I noticed that in histogram/Value we do not see the graph beyond the value 1.0, while in Histogram/R,G,B and RGB Parade we see these values.
чт, 9 нояб. 2023 г., 13:37 Andrea paz <[email protected]>:
I did further testing by paying attention to the operation of other plugins in the Histogram queue and always monitoring CPU and RAM usage. So far I have not noticed any differences with appimage which does not have the modification. I only have a few old projects involving CC, but they were loaded correctly and I don't seem to notice any differences. No error lines appear on the terminal. PS: I noticed that in histogram/Value we do not see the graph beyond the value 1.0, while in Histogram/R,G,B and RGB Parade we see these values.
well, may be file a bug then? I think HV at least in git I checked yesterday does have those lines with input/output clipping, still not tried to contact Adam on any of this yet .... https://github.com/heroineworshiper/hvirtual/blob/master/plugins/histogram/h... line 323/342
participants (3)
-
Andrea paz -
Andrew Randrianasulu -
Phyllis Smith