Following is the status of an image that I have:
ExifTool Version Number : 12.42
File Type : TIFF
MIME Type : image/tiff
Exif Byte Order : Little-endian (Intel, II)
Subfile Type : Full-resolution image
Bits Per Sample : 8 8 8 8
Compression : LZW
Photometric Interpretation : RGB
Samples Per Pixel : 4
Rows Per Strip : 1
Planar Configuration : Chunky
Predictor : Horizontal differencing
The extra samples count is 0. What does this mean? What is the extra 8 bits present in the data?