FFmpeg&FFPlay: Option `start`&`end` of filter `trim` have trouble parsing time duration string but `-ss`&`-to` works perfectly

Question

I'm tring to preview cut video before process it on Windows, this Cut.bat is what I tried:

@echo off
@cd/d %~dp0

REM Entered by user
set startTime1=5
REM Entered by user
set startTime2=00:05
REM Entered by user
set toTime1=13
REM Entered by user
set toTime2=00:13

echo [96mPreviewing...press any key to process[0m

REM No, ffplay don't support `-to` option
REM ffplay  -i in.mp4  -ss %startTime1%  -to %toTime1%  out1.mp4

REM Result: 8 seconds long video preview, start from 00:05 (correct)
ffplay  -i in.mp4  -vf trim=start=%startTime1%:end=%toTime1%,setpts=PTS-STARTPTS -af atrim=start=%startTime1%:end=%toTime1%,asetpts=PTS-STARTPTS

REM Result: 13 seconds long video preview, start from 00:00
ffplay  -i in.mp4  -vf trim=start=%startTime2%:end=%toTime1%,setpts=PTS-STARTPTS -af atrim=start=%startTime2%:end=%toTime1%,asetpts=PTS-STARTPTS

REM Result: failed to preview so I commented it out
REM ffplay  -i in.mp4  -vf trim=start=%startTime1%:end=%toTime2%,setpts=PTS-STARTPTS -af atrim=start=%startTime1%:end=%toTime2%,asetpts=PTS-STARTPTS

REM Result: failed to preview so I commented it out
REM ffplay  -i in.mp4  -vf trim=start=%startTime2%:end=%toTime2%,setpts=PTS-STARTPTS -af atrim=start=%startTime2%:end=%toTime2%,asetpts=PTS-STARTPTS

pause

REM Result: All of them are 8 seconds long videoes, start from 00:05 (correct)
ffmpeg  -i in.mp4  -ss %startTime1%  -to %toTime1%  -c copy  out1.mp4
ffmpeg  -i in.mp4  -ss %startTime2%  -to %toTime1%  -c copy  out2.mp4
ffmpeg  -i in.mp4  -ss %startTime1%  -to %toTime2%  -c copy  out3.mp4
ffmpeg  -i in.mp4  -ss %startTime2%  -to %toTime2%  -c copy  out4.mp4

pause

The document said all of them support time duration expression, it's true for -ss and -to, but not working well with start & end of trim

Since startTime & toTime are entered by user (myself) so I hope to write it freely instead of using strict format

• Did I wrote it wrong? If so, what's the correct syntax?
• Is there any other simple and/or reliable way to achieve my goal?

Answer 1

According to this answer, it's an escape trick (I have to say the escape syntax of ffmpeg is a good example of spaghetti

The correct syntax would be:

set startTime2Es=%startTime2::=\:%
set toTime2Es=%toTime2::=\:%

ffplay  -i in.mp4  -vf "trim=start='%startTime2Es%':end='%toTime2Es%',setpts=PTS-STARTPTS" -af "atrim=start='%startTime2Es%':end='%toTime2Es%',asetpts=PTS-STARTPTS"

instead of

ffplay -i in.mp4 -vf trim=start=%startTime2%:end=%toTime2%,setpts=PTS-STARTPTS -af atrim=start=%startTime2%:end=%toTime2%,asetpts=PTS-STARTPTS