SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
Figure 9-160 shows the A-Law compression block diagram.
An optional 10-to-8-bit A-Law compression using a fixed A-Law table can be applied (the ISIF_CGAMMAWD[0] CCDTBL bit) as the final processing stage. Using this compression causes the data width to be reduced to 8 bits and allows packing to 8 bits/pixel when saving to memory. Because data resolution can be greater than 10 bits at this stage, the 10 bits for input to the A-Law operation must be selected (the ISIF_CGAMMAWD[4:1] GWDI bit field).
The IPIPEIF module has an inverse A-Law table (A-Law decompression) option so that this nonlinear operation can be reversed if this saved data is to be read back in for further processing.
Do not use A-Law compression (ISIF_CGAMMAWD[0] CCDTBL = 0) with YUV data.
Figure 9-161 shows the A-Law table diagram, and Figure 9-162 shows the A-Law table values.