Not sure if it would be used enough to warrant an OliveTin Action.
I just use a simple script (Windows cmd file) that runs an ffmpeg remux against the recording (logging the ffmpeg output) and saves it as a .ts file (which is really what CDVR records to), optionally in the same directory as the recording. That way I can check the remux to see if it fixed it, and if so I move it over the original recording, replacing the recorded.mpg.
To do that, I drag and drop the recording on this Windows cmd file which exists on a local drive
ffmpeg_remux.cmd
@ECHO OFF
ECHO ...
IF %1.==. GOTO USAGE
REM Change current working directory to where this command script resides
%~d0
CD %~p0
REM Use your ffmpeg.exe to remux the recording to a new .ts file in the current directory
REM and redirect standard and error output to originalfilename_remux_log.txt
ECHO Remuxing %1
ffmpeg -ignore_unknown -i %1 -map 0 -acodec copy -vcodec copy -scodec copy "%~dp0%~n1.ts" > "%~n1_remux_log.txt" 2>&1
ECHO Remuxed %1
ECHO to file "%~dp0%~n1.ts"
ECHO Press Ctrl-C to keep remuxed file here, or to move it to the original directory
PAUSE
REM Move the remuxed file.ts so as not to overwrite the original.mpg
MOVE /Y "%~dp0%~n1.ts" "%~dp1"
GOTO FINISHED
:USAGE
REM Need the fully qualified filename.mpg to remux
ECHO Drop the file to be remuxed on this command file
:FINISHED
PAUSE
EXIT