Why doesn't the video waveform even change when you change the range control?

It correctly updates with YUV content, just not with RGB.

What is it showing?

Should be showing the XYZ values that will go into the DCP; calls DCPVideo::convert_to_xyz() which gets its image from PlayerVideo::make_image()

Looks like the return from PlayerVideo::make_image() should always be full-range; call to sws_setColorspaceDetails in Image::crop_scale_window tries to achieve that. Although the comment there says that this method only changes the range from in to out if the image is YUV or grayscale (?!). So presumably image file inputs e.g. DPX will not be changed; which is OK if they are already full range.

But if the video range control is going to work for all input types we need to do the transformation ourselves for non isYUV/isGray images; i.e. basically RGB i.e. still images. Could try adding a filter to the FFmpeg decoder

perhaps -vf scale=in_range=limited:out_range=full

or just do it ourselves (but would require a method for each supported pixel format).

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