how to do a mathematical subtraction in a batch

[marcorocchini]

Hi

and however


I'm inside a batch where I get the video duration in a string called %aviGenDuration%

FFProbe.exe -loglevel fatal -show_entries format=duration -of csv="p=0" -sexagesimal "%~nx1.ts">aviGenDuration.txt   

set /p aviGenDuration=<aviGenDuration.txt

for example the result is:

0:01:30.680000

I wonder how can I do a mathematical subtraction so that the result is 4 millisecond less than the result. In this case the final result have to be

0:01:30.640000

is there a way? thanks

[Cornucopia]

You must parse it into its elements, convert from string to numerical, build it up into one figure of the smallest element, do the math, convert back to string, then re-separate into segments with delimiters re-added in. DONE.


Scott

[marcorocchini]

oh yes, it'all clear

[Attachment 66676 - Click to enlarge]

[jack_666]

this may be of help

https://stackoverflow.com/questions/9922498/calculate-time-difference-in-windows-batch-file

[jagabo]

This is the clearest example I've found.

https://stackoverflow.com/questions/605522/print-time-in-a-batch-file-milliseconds

@echo off
setlocal

rem The format of %TIME% is HH:MM:SS,CS for example 23:59:59,99
set STARTTIME=%TIME%

rem here begins the command you want to measure
dir /s > nul
rem here ends the command you want to measure

set ENDTIME=%TIME%

rem output as time
echo STARTTIME: %STARTTIME%
echo ENDTIME: %ENDTIME%

rem convert STARTTIME and ENDTIME to centiseconds
set /A STARTTIME=(1%STARTTIME:~0,2%-100)*360000 + (1%STARTTIME:~3,2%-100)*6000 + (1%STARTTIME:~6,2%-100)*100 + (1%STARTTIME:~9,2%-100)
set /A ENDTIME=(1%ENDTIME:~0,2%-100)*360000 + (1%ENDTIME:~3,2%-100)*6000 + (1%ENDTIME:~6,2%-100)*100 + (1%ENDTIME:~9,2%-100)

rem calculating the duratyion is easy
set /A DURATION=%ENDTIME%-%STARTTIME%

rem we might have measured the time inbetween days
if %ENDTIME% LSS %STARTTIME% set set /A DURATION=%STARTTIME%-%ENDTIME%

rem now break the centiseconds down to hors, minutes, seconds and the remaining centiseconds
set /A DURATIONH=%DURATION% / 360000
set /A DURATIONM=(%DURATION% - %DURATIONH%*360000) / 6000
set /A DURATIONS=(%DURATION% - %DURATIONH%*360000 - %DURATIONM%*6000) / 100
set /A DURATIONHS=(%DURATION% - %DURATIONH%*360000 - %DURATIONM%*6000 - %DURATIONS%*100)

rem some formatting
if %DURATIONH% LSS 10 set DURATIONH=0%DURATIONH%
if %DURATIONM% LSS 10 set DURATIONM=0%DURATIONM%
if %DURATIONS% LSS 10 set DURATIONS=0%DURATIONS%
if %DURATIONHS% LSS 10 set DURATIONHS=0%DURATIONHS%

rem outputing
echo STARTTIME: %STARTTIME% centiseconds
echo ENDTIME: %ENDTIME% centiseconds
echo DURATION: %DURATION% in centiseconds
echo %DURATIONH%:%DURATIONM%:%DURATIONS%,%DURATIONHS%

endlocal
goto :EOF

Unfortunately it's only precise to 2 decimal places. It should be pretty easy to modify to 3 (or more).

[marcorocchini]

interesting ***

but maybe my specific question is well explained here:
https://forum.videohelp.com/threads/406954-How-to-get-the-wav-pcm_s16-from-this-mp4

thanks

[Cornucopia]

No clearer than the original question, both of which have been answered multiple times (by me, genericly, and by jack_666 and jagabo specificly).

Scott