@echo off
::Parameters
set "CHDMAN_DIR=C:\Folder\With\chdman\"
set /P OUT_DIR=["Specify output directory without quotes. Leave blank for current directory:"]

if not defined OUT_DIR (for /r %%i in (*.cue, *.iso, *.gdi) do "%CHDMAN_DIR%\chdman" createcd -i "%%i" -o "%%~ni.chd") else (for /r %%i in (*.cue, *.iso, *.gdi) do "%CHDMAN_DIR%\chdman" createcd -i "%%i" -o "%OUT_DIR%\%%~ni.chd")