Hopefully will not offend anyone as off-topic because it does relate to the OP's question. And I don't believe this has been discussed in any detail in the forum ?
So does it assume that the image processing software has a file with the bad pixel map ? Or is the map imbedded in the DNG ?
Will it use a badpixel.bin file if you have one ?No. It sets an opcode in the DNG file to tell whatever file is processing the image to map out bad pixels.
The opcode tells the processing software what sensor pixel value to treat as a 'bad' pixel (CHDK uses a value of 0). It's up to the software to decide how to map out the bad pixels.
So far it seems only Adobe software has implemented support for DNG 1.3.So does other s/w fail to read 1.3 files ? Which might imply we have come almost full circle back to not being able to read CHDK RAW if so ...
No, the CHDK DNG files are set with the 'backward compatible' version to 1.1.
The DNG standard specifies that processing software that does not understand the new stuff can ignore it.
This is what happens with other software (e.g. RawTherapee) - it loads the DNG files; but does not fix the bad pixels.
It's still not a perfect answer (unless you only use Adobe software).