As far as I know, no metadata records whether any data is clipped, or at the maximum posible value.
The fastest solution would be a custom program written for the libraw (or similar) library. No need for demosaicing or a temporary file; just read the pixel data, and count the number of pixel values that are at the maximum. (Or count the number of pixels that have any values at the maximum, which isn’t the same thing.) Divide by the number of pixels to get the proportion that are at max.
The program could accept multiple input raw files, and determine the one with the “best” exposure. This isn’t as easy as it sounds: most of my photos contain specular highlights that have blown, and I don’t care.
Better still, the program could read all the raws from a day’s shooting, figure out the sets of photos are like others except for exposure, and toss the bad ones from each set into the bin.
Read more here: Source link