Usually 1 = grey scaled, 3 = color YcbCr or YIQ, 4 = color CMYK
Each component TAG_COMPONENT_DATA_[1-4], has the following meaning:
component Id(1byte)(1 = Y, 2 = Cb, 3 = Cr, 4 = I, 5 = Q),
sampling factors (1byte) (bit 0-3 vertical., 4-7 horizontal.),
quantization table number (1 byte).
Three values:
Value 1: 0=Normal, 2=Fast, 3=Panorama
Value 2: Sequence Number Value 3:
1 = Panorama Direction: Left to Right
2 = Panorama Direction: Right to Left
3 = Panorama Direction: Bottom to Top
4 = Panorama Direction: Top to Bottom
Decides whether a brute-force simplification calculation should be avoided
by comparing the maximum number of possible calculations with some threshold.