Padding Bits Recovery is tool that used to recover missing terminator and padding bits of QR code automatically.
I assume that you already know about how data encoding works in QR code before using this tool.
As we already know that if the message bit string is shorter than the total number of required bits, QR code should be padded with terminator and padding bits until it reach the required number of bits.
Terminator always consists of 0 value of their modules and Padding bits always consists of alternate value between 11101100 and 00010001. Therefore, we can exploit that to automatically recover some missing bits in QR code.
This tool can be used when QR code meets the following conditions :
It contains at least four values of Terminator (0000) at the end of message bit string
It contains one or more Encoding mode indicator
It contains Character count indicator right after encoding mode indicator
Otherwise, the tool will throw error when the above conditions are not fulfilled.
(The dialog of Padding Bits Recovery. The green-colored modules indicating recovered/affected modules)
In certain cases, this tool can also throw a warning when the recovered modules are overwritting modules that are not grey-colored.
When that happen, you have an option to ignore the warning or cancel the operation. Be careful though, overwriting already known modules may cause addition of the Error in QR code.
You can undo this operation anytime through History
Further details about the implementation of this tool can be seen in the example section.