Batch Script Chokes on ! Exclamation Point in Filename

The Batch file below fails to encode any .mkv file with an exclamation point (!) in the filename.

Not sure what the problem is.

@echo off
SETLOCAL EnableDelayedExpansion

rem <BUG>If the input .mkv filename contains a ! (exclamation mark), the script will not encode the file and continue to the next file

echo Handbrake_Encode_MKV_offPeak-beta.bat

for /r %%a in (*.mkv) do (
rem call function to pause script until electricity rates are lowest
call :sleepUtilOffPeak

rem strip parent directory from the path (set str = filename.ext)
rem set str=%%~nxa
rem strip extension from filename
rem set str=!str:~0,-4!

rem get filename and drive+path
set filename=%%~na
set drive_and_path=%%~dpa

rem echo Calling Handbrake to encode^: !str!.mp4
echo Calling Handbrake to encode^: !drive_and_path!!filename!.mp4

 	"C:\Scripts\HandBrakeCLI.exe" -v 0 --preset-import-file "C:\Scripts\Fast 1080p30-subs.json"	-Z "Fast 1080p30-subs" -i "%%a" -o "!drive_and_path!!filename!.mp4"
)
echo encoding complete. Exiting...
exit /B 0

The Handbrake log complains about a "Missing output file name"

Handbrake_Encode_MKV_offPeak-beta.bat
Day of week: 0
Hour: 14
Minute: 43
Today is a weekend
14 is not less than off-peak end : 14
14 is between 14 and 24
Going to sleep for 33420 seconds
All done sleeping. Time to work...
Calling Handbrake to encode: E:\Mamasota\Unsorted\dvds\_Encode\mkv\Scooby-Doo and Kiss Rock and Roll Mystery (2015).mp4
[00:00:13] Compile-time hardening features are enabled
[00:00:13] qsv: not available on this system
[00:00:13] vcn: not available on this system
Cannot load nvEncodeAPI64.dll
[00:00:14] hb_init: starting libhb thread
[00:00:14] thread 1 started ("libhb")
Missing output file name. Run C:\Scripts\HandBrakeCLI.exe --help for syntax.
HandBrake has exited.

To see what is being passed as input to Handbrake when the filename (Scooby-Doo!) includes an exclamation point:

echo "%%a"

The output was:

Scooby-Doodrive_and_path

Using

setlocal DisableDelayedExpansion

before calling Handbrake corrects the input file name but the output filename is not expanded?

Calling Handbrake to encode: "Scooby-Doo! & Batman The Brave and the Bold (2018).mkv" to !drive_and_path!!filename!.mp4

I also tried reading similar threads but I'm not sophisticated enough to understand what I'm doing wrong.

tl;dr: Remove the variables entirely and just use %%~dpna.mp4 as the output filename.

<hr>

When you enable delayed expansion, ! becomes a character that has special meaning - it indicates to the interpreter that the variable should have its value expanded when the line is executed rather than when the line is initially read in. If you're simply printing a ! with delayed expansion enabled, you can escape it with a ^ so that it displays correctly. However, since you're iterating over filenames, you have no way of escaping !s in filenames so the only way to correctly process them is to disable delayed expansion.

Unfortunately, since you're trying to set and use the filename and drive_and_path variables inside of a set of parentheses, you have to use delayed expansion if you want those variables to have usable values inside of the loop. This is because a set of parentheses is read in and treated as a single command in batch. Since you aren't doing any sort of string manipulation with those variables like getting substrings or doing substitutions, you can get around this limitation by removing the variables entirely and simply using %%~dpna wherever in the code you want to use !drive_and_path!!filename!.