Carousel: Background color and text color of the caption

[fdagner]

The background of the carousel is white by default, as is the font color of the caption.
This leads to problems if the images are in portrait format, adapt responsively or no images are used at all. The white color is also not so good for pictures with bright colors, for example. Of course, this can affect all colors.
What do you think of placing a semi-transparent bar behind the text?