HSL filters modify the light for BT.601 videos after export

[meiber]

Bonjour.

Les filtres HSL Modifie la lumiere uniquement pour les video bt 601 apres exportation, ( J’ai pas essayé avec les autres espace de couleur 2020).

Ces filtres comprennent aussi le filtre vibrance, le filtre teinte, luminosité saturation.

Pour eviter le probleme d’ecart de luminosité apres exportation, il faut ajouter une LUT de conversion vers BT 709, ( sans aucune opacité ).

Pourrait 'on avoir la possibilitée d’utiliser les filtres HSL, pour les video en BT 601, sans avoir de probleme de luminosité apres exportation, et sans devoir utiliser une LUT de conversion vers BT 709.

Hello.

HSL filters only modify the brightness of BT.601 videos after export (I haven’t tried them with other 2020 color spaces).

These filters also include vibrance, hue, brightness, and saturation filters.

To avoid brightness discrepancies after export, a LUT (Look-Up Tool) must be added to convert to BT.709 (without any opacity).

Is it possible to use HSL filters for BT.601 videos without brightness issues after export and without needing a BT.709 conversion LUT?

[brian]

Steps to reproduce using 25.12.31 on Windows 11

First create a 601 clip:

1. Open Shotcut
2. Set the video mode to SD NTSC & Processing Mode to Native 8-bit CPU
3. Open New Generator → Colorbars and put the clip on the timeline
4. Export the colorbars as an mp4 file (colorbars_sd.mp4)

Then, run the test

1. Open Shotcut
2. Set the video mode to HD 1080p 24 fps & Processing Mode to Native 8-but CPU
3. Open the Video Waveform Scope
4. Open the 601 file (colorbars_sd.mp4)
5. Move the clip to the timeline
6. Click on the clip and add a filter: HSL Primaries
7. Increment the Reds Hue Shift from 0 to 1.

Notice in the Video Waveform Scope that changing the value by one changes the brightness of all the other colors.

[meiber]

Hue Red 0

Uploading: Hue Red 0 = avant.jpg…

Hue Red 1