ffmpeg - removing X seconds from start and end of video

[Ygramul]

Let's say I have ten .mp4 files that vary in length. I want to remove the first 30 and the last 10 seconds from each of them and save the output in a folder called "trimmed". I made ChatGPT write the script because the part about using ffprobe to calculate the removal of the last 10 seconds is too complicated for me. Unfortunately, I keep getting errors. This is version 1:

https://pastebin.com/ykLk6Awn

The result is this error:

\FFmpeg was unexpected at this time.

Then I made ChatGPT make corrections and it did the following:

Removed quotes from set ffmpeg_path=...

Wrapped "%ffmpeg_path%" and "%ffprobe_path%" with quotes only when used.

https://pastebin.com/6tJyDnjE

But this script doesn't work, either:

'C:\Program' is not recognized as an internal or external command, operable program or batch file.

What am I doing wrong?

[cholla]

I do not know how to do this with a script like in the link.
If you want to do this with each file separately this will work:

ffmpeg -i input.mp4 -ss 00:00:30 -t -c copy C:\trimmed\output.mp4

-t needs to equal the length of the video - 10 seconds. in HH:MM:SS

Maybe you can apply this to a script.

[Ygramul]

I do not know how to do this with a script like in the link.
If you want to do this with each file separately this will work:

ffmpeg -i input.mp4 -ss 00:00:30 -t -c copy C:\trimmed\output.mp4

-t needs to equal the length of the video - 10 seconds. in HH:MM:SS

Maybe you can apply this to a script.

Thanks, but the whole point is that I have 700+ files and each has a different length.

[pcspeak]

This requires:
https://mediaarea.net/download/binary/mediainfo/25.04/MediaInfo_CLI_25.04_Windows_x64.zip as well as ffmpeg.exe
Change the path in the batch file to suit the correct location.
trim-start-end-v01.cmd

@echo off
set mediainfo=C:\MediaInfoCLI\mediainfo.exe
if not exist trimmed\ md trimmed
for %%a in ("*.mp4", "*.mkv") do call :process "%%a"
goto :end

:process
set video=%~1
"%mediainfo%" "--Output=Video;%%Duration%%" "%video%" > tmp.txt
set /p Duration= < tmp.txt
echo WScript.Echo eval(%Duration% / 1000) > eval.vbs
for /f "tokens=1 delims=." %%a in ('cscript.exe //nologo eval.vbs %%a') do set /a length=%%a-10

ffmpeg.exe -ss 30 -to %length% -i "%~1" -c copy -y "trimmed\%~1"
set Duration=
set length=
del tmp.txt
goto :eof

:end
pause

It's possible to pass input parameters to ffmpeg in straight seconds, rather than 00:00:00.000
Cheers

EDIT: p.s. Your profile says you're running Windows XP SP2. I tested on Win11

[Ygramul]

EDIT: p.s. Your profile says you're running Windows XP SP2. I tested on Win11

Haha, I didn't even notice the Windows XP thing. I just realized that I registered in 2007, so I must've been using that OS then.

Thanks for the script, but it doesn't cut the last 10 seconds. I assume that it's the part that says length=%%a-10
that's responsible for this. I changed it to 50 just to test it and it doesn't make a difference.

By the way, there's one detail I completely missed because I seldom use ffmpeg and that's setting it as a system environment variable. I'm not sure, but I think that setting the path for ffmpeg.exe in the script doesn't work without that.

[cholla]

I wanted to play with this but I'm not very experienced in using a script like this.
What location do I use for the input files?

These are the errors I got:

Invalid duration for option to: %length%
Error parsing options for input file %~1.
Error opening input files: Invalid argument

[pcspeak]

I'm not sure, but I think that setting the path for ffmpeg.exe in the script doesn't work without that.

. You're right. I keep ffmpeg, ffprobe & ffplay in

Path=C:\WINDOWS\system32

The batch file works for me.
When using -c copy, ffmpeg will trim at the nearest keyframe (I-frame), which might not be exactly where you specified. I've had videos with keyframes 5 seconds apart.
For more precise trimming you will probably have to re-encode each video. Or use another program, maybe.

[pcspeak]

What location do I use for the input files?
These are the errors I got:

Invalid duration for option to: %length%
Error parsing options for input file %~1.
Error opening input files: Invalid argument

The batch file goes in with the videos. Start with 1 video in the folder.
As Ygramul stated you may need to add the path to ffmpeg.exe to the batch file.

trim-start-end-v02.cmd

@echo off
set mediainfo=C:\MediaInfoCLI\mediainfo.exe
set ffmpeg_path="C:\Program Files (x86)\FFmpeg 6.0\bin\ffmpeg.exe"
if not exist trimmed\ md trimmed
for %%a in ("*.mp4", "*.mkv") do call :process "%%a"
goto :end

:process
set video=%~1
"%mediainfo%" "--Output=Video;%%Duration%%" "%video%" > tmp.txt
set /p Duration= < tmp.txt
echo WScript.Echo eval(%Duration% / 1000) > eval.vbs
for /f "tokens=1 delims=." %%a in ('cscript.exe //nologo eval.vbs %%a') do set /a length=%%a-10

"%ffmpeg_path%" -ss 30 -to %length% -i "%~1" -c copy -y "trimmed\%~1"
set Duration=
set length=
del tmp.txt
goto :eof

:end
pause

Comment out the line 'del tmp.txt'. Check to see if tmp.txt has any content.

[videoAI]

The provided batch script has a few issues that need to be addressed:

1. The `setlocal` command should be used to ensure that environment variables are local to the script.
2. The `endlocal` command should be used to end the localization of environment variables.
3. The `goto :eof` command should be used to exit the script properly.
4. The `for /f` loop should handle the duration correctly.
5. The `ffmpeg` command should be correctly formatted to handle the input and output files.

Here is the corrected version of the script:

```batch
@echo off
set ffmpeg_path="C:\Program Files (x86)\FFmpeg 6.0\bin\ffmpeg.exe"
set ffprobe_path="C:\Program Files (x86)\FFmpeg 6.0\bin\ffprobe.exe"

md trimmed

for %%a in ("*.mp4") do (
for /f "tokens=* usebackq" %%b in (`"%ffprobe_path%" -v error -show_entries format^=duration -of default^=noprint_wrappers^=1:nokey^=1 "%%a"`) do (
call rocess "%%a" %%b
)
)
goto :eof

rocess
setlocal
set file=%~1
set duration=%~2

rem Remove fractional seconds
for /f "tokens=1 delims=." %%d in ("%duration%") do set /a new_end=%%d - 10

rem Format the new duration in HH:MM:SS
set /a hh=new_end / 3600
set /a mm=(new_end %% 3600) / 60
set /a ss=new_end %% 60

rem Pad with zeros
if %hh% lss 10 set hh=0%hh%
if %mm% lss 10 set mm=0%mm%
if %ss% lss 10 set ss=0%ss%

set end_time=%hh%:%mm%:%ss%

echo Trimming %file% from 00:03:00 to %end_time%
"%ffmpeg_path%" -i "%file%" -ss 00:03:00 -to %end_time% -c:v copy -c:a copy "trimmed\%%~nxa"
endlocal
goto :eof
```

### Explanation of Changes:
1. **Localization of Environment Variables**: The `setlocal` command is used at the beginning of the `rocess` label to ensure that environment variables are local to the script. The `endlocal` command is used at the end to end the localization.
2. **Correct Handling of File Paths**: The `ffmpeg` command now correctly handles the input and output file paths by using double quotes around the file names.
3. **Correct Handling of Duration**: The `for /f` loop correctly handles the duration by removing fractional seconds and formatting the new duration in HH:MM:SS format.
4. **Proper Exit**: The `goto :eof` command is used to exit the script properly.

This script should now correctly trim the specified duration from each `.mp4` file in the directory and save the trimmed files in the `trimmed` folder.

[cholla]

I figured out where to put the video file or files.
In the MediaInfo_CLI folder.
I do not have ffprobe in the Environment path but I do have ffmpeg in it.
So I will put ffprobe there also.

The only problem I had is the total video duration does not show the 10 seconds off at the end.
It does show the 30 seconds off the beginning.

@ VideoAI, I copied the script you posted & it did not do anything.
Maybe if you post it in code tags I can do it better.
Like pcspeak did.

[pcspeak]

The only problem I had is the total video duration does not show the 10 seconds off at the end.

I just tested again. It most definitely works here.
Try chopping off 60 seconds. If that fails then I'm lost as to what is different between our methods.

[cholla]

@ pcspeak,
I did not do the script exactly as you suggested in the last post.
I cut 7 seconds off the beginning & 12 off the end.
The cuts were made but the duration time is incorrect.
The first video is the original. Video1.mp4
It shows 7:35 for the total duration.
The second is the cut video.Video2.mp4
It shows 7:28 for the total duration.
It ends about 7:16 total duration.
The 7:35 minus 19 seconds is 7:16.

[pcspeak]

Video1.mp4 has a keyframe every 250 frames.
@29.97fps this is every 8.33 seconds.
ffmpeg cuts at the nearest keyframe. Each cut could differ from your requirements by as much as 4 seconds.
(approximately. I've used rounding. )

[cholla]

Video1.mp4 has a keyframe every 250 frames.
@29.97fps this is every 8.33 seconds.
ffmpeg cuts at the nearest keyframe. Each cut could differ from your requirements by as much as 4 seconds.
(approximately. I've used rounding. )

I appreciate the math.
When I use ffmpeg with code direct.
I get this result: with ffmpegcut.mp4

ffmpeg -i C:\Users\USER\Desktop\Temp\sweet_emotion.mp4 -ss 00:00:07 -to 00:07:23 -c copy C:\Users\USER\Desktop\Work\ffmpegcut.mp4

It is spot on including duration.

[pcspeak]

Good. In the last video, every frame is an keyframe, so all cuts will be frame accurate.
it makes for a larger file, but great for editing.
Cheers.

[cholla]

The ffmpegcut.mp4 is smaller that the other two.

The OP posted he has around 700 files to do.
All different lengths.
This is why he needs a batch script that will detect the length & make the cuts accordingly.
The scripts posted did not do this for me.
But I'm just trying to learn & playing around.

The one videoAI posted did not work for me at all.

[videoAI]

@cholla

Here you go ..

@echo off
set ffmpeg_path="C:\Program Files (x86)\FFmpeg 6.0\bin\ffmpeg.exe"
set ffprobe_path="C:\Program Files (x86)\FFmpeg 6.0\bin\ffprobe.exe"

md trimmed

for %%a in ("*.mp4") do (
for /f "tokens=* usebackq" %%b in (`"%ffprobe_path%" -v error -show_entries format^=duration -of default^=noprint_wrappers^=1:nokey^=1 "%%a"`) do (
call :Process "%%a" %%b
)
)
goto :eof

:Process
setlocal
set file=%~1
set duration=%~2

rem Remove fractional seconds
for /f "tokens=1 delims=." %%d in ("%duration%") do set /a new_end=%%d - 10

rem Format the new duration in HH:MM:SS
set /a hh=new_end / 3600
set /a mm=(new_end %% 3600) / 60
set /a ss=new_end %% 60

rem Pad with zeros
if %hh% lss 10 set hh=0%hh%
if %mm% lss 10 set mm=0%mm%
if %ss% lss 10 set ss=0%ss%

set end_time=%hh%:%mm%:%ss%

echo Trimming %file% from 00:03:00 to %end_time%
"%ffmpeg_path%" -i "%file%" -ss 00:03:00 -to %end_time% -c:v copy -c:a copy "trimmed\%%~nxa"
endlocal
goto :eof

[Ygramul]

@cholla

I'm still getting

\FFmpeg was unexpected at this time.

and that's it, nothing else happens. What does that error even mean?

[cholla]

@ videoAI ,
I just get a quick flash of the command prompt.
Too fast to read.
No file created.
I did change the path to ffmpeg & ffprobe to match my OS.

[pcspeak]

I'm still getting

\FFmpeg was unexpected at this time.

and that's it, nothing else happens. What does that error even mean?

My apologies for partially hijacking your thread.

Please, post your batch file here for us to look at.
Also the full screen output from the batch file.
I find the easiest way to do that is to tack 2> log.txt to the end of the ffmpeg command.
e.g.

ffmpeg.exe -ss 30 -to 1024 -i "%~1" -c copy -y "trimmed\%~1" 2> log.txt

Post the content of log.txt here, wrapping the text with the CODE tags. ( # symbol in the formatting menu)

[pcspeak]

Just a quick note:-
I try to keep in mind that there may be new VideoHelp Forum members, and novices to batch files, reading these posts.
So, I may tend to over-explain myself.


Na!

[_Al_]

@ videoAI ,
I just get a quick flash of the command prompt.
Too fast to read.
No file created.
I did change the path to ffmpeg & ffprobe to match my OS.

videoAI wrote what was all wrong with posted batch script, (most likely there was nothing wrong with it) and unfortunately took away "pause" command from the end of script. That part causes cmd prompt to freeze, if there was an error (or not), so you can actually read what went wrong.

[videoAI]

Upload, using code tags, this part from your code:

@echo off
set ffmpeg_path="C:\Program Files (x86)\FFmpeg 6.0\bin\ffmpeg.exe"
set ffprobe_path="C:\Program Files (x86)\FFmpeg 6.0\bin\ffprobe.exe"

@cholla

I'm still getting

\FFmpeg was unexpected at this time.

and that's it, nothing else happens. What does that error even mean?

[videoAI]

Please, post your batch file here for us to look at.
Also the full screen output from the batch file.
I find the easiest way to do that is to tack 2> log.txt to the end of the ffmpeg command.
e.g.

ffmpeg.exe -ss 30 -to 1024 -i "%~1" -c copy -y "trimmed\%~1" 2> log.txt

Post the content of log.txt here, wrapping the text with the CODE tags. ( # symbol in the formatting menu)

.........

[davexnet]

I found that by copying ffprobe.exe and ffmpeg.exe into the same folder as the bat file and video files,
it simplifies things for those new to BAT file scripting. (Myself included)
I disabled the "echo off" and added a "Pause" to allow examination of the script execution.

rem @echo off
set ffmpeg_path1=ffmpeg.exe
set ffprobe_path1=ffprobe.exe

rem md trimmed

for %%a in ("*.mp4") do (
for /f "tokens=* usebackq" %%b in (`%ffprobe_path1% -v error -show_entries format^=duration -of default^=noprint_wrappers^=1:nokey^=1 "%%a"`) do (
call :Process "%%a" %%b
)
)
pause
goto :eof

:Process
setlocal
set file=%~1
set duration=%~2

rem Remove fractional seconds
for /f "tokens=1 delims=." %%d in ("%duration%") do set /a new_end=%%d - 10

rem Format the new duration in HH:MM:SS
set /a hh=new_end / 3600
set /a mm=(new_end %% 3600) / 60
set /a ss=new_end %% 60

rem Pad with zeros
if %hh% lss 10 set hh=0%hh%
if %mm% lss 10 set mm=0%mm%
if %ss% lss 10 set ss=0%ss%

set end_time=%hh%:%mm%:%ss%

echo Trimming %file% from 00:03:00 to %end_time%
%ffmpeg_path1% -i "%file%" -ss 00:00:03 -to %end_time% -c:v copy -c:a copy "trimmed\%file%"
endlocal
goto :eof

[pcspeak]

I found that by copying ffprobe.exe and ffmpeg.exe into the same folder as the bat file and video files,
it simplifies things for those new to BAT file scripting. (Myself included)
I disabled the "echo off" and added a "Pause" to allow examination of the script execution.

That's why I suggested redirecting the output from ffmpeg to log.txt. One then has a hard copy to look back on. At lease until the next run.

 rem Remove fractional seconds
 for /f "tokens=1 delims=." %%d in ("%duration%") do set /a new_end=%%d - 10

rem Format the new duration in HH:MM:SS
set /a hh=new_end / 3600
set /a mm=(new_end %% 3600) / 60
set /a ss=new_end %% 60

rem Pad with zeros
if %hh% lss 10 set hh=0%hh%
if %mm% lss 10 set mm=0%mm%
if %ss% lss 10 set ss=0%ss%

Post #4: It's possible to pass input parameters to ffmpeg in straight seconds, rather than 00:00:00.000

"ffmpeg -ss 30 -to 1211 -i video_in.mp4 -c copy -y video_out.mp4" works, and is easier to code.

[aramkolt]

Just checking, do the above methods not re-encode the video in any way? So in other words, do they just create a new key frame at the "new" beginning if there isn't already one there and the rest is a copy of the original?

[Ygramul]

Upload, using code tags, this part from your code:

@echo off
set ffmpeg_path="C:\Program Files (x86)\FFmpeg 6.0\bin\ffmpeg.exe"
set ffprobe_path="C:\Program Files (x86)\FFmpeg 6.0\bin\ffprobe.exe"

It's exactly the same in my script.

Just checking, do the above methods not re-encode the video in any way? So in other words, do they just create a new key frame at the "new" beginning if there isn't already one there and the rest is a copy of the original?

It's all supposed to be keyframe based, yes. Re-encoding all those files would take ages, so I don't have any interest in that.

[cholla]

I find the easiest way to do that is to tack 2> log.txt to the end of the ffmpeg command.
e.g.

ffmpeg.exe -ss 30 -to 1024 -i "%~1" -c copy -y "trimmed\%~1" 2> log.txt

Post the content of log.txt here, wrapping the text with the CODE tags. ( # symbol in the formatting menu)

Where in the batch script is the code above?
Where did the 1024 come from?

ffmpeg -ss 30 -to 1211 -i video_in.mp4 -c copy -y video_out.mp4

works, and is easier to code.

Where did the now 1211 come from?

This part of your batch file has "legnth".
This is missing is videoAI's & davexnet's batch files.
How would their batch files determine "legnth" ?

for /f "tokens=1 delims=." %%a in ('cscript.exe //nologo eval.vbs %%a') do set /a length=%%a-10

"%ffmpeg_path%" -ss 30 -to %length% -i "%~1" -c copy -y "trimmed\%~1"

[/QUOTE]

@ davexnet.You batch script actually worked pretty well.
I made these modifications specific to the file I was testing with:

for /f "tokens=1 delims=." %%d in ("%duration%") do set /a new_end=%%d - 12 echo Trimming %file% from 00:00:00 to %end_time%
%ffmpeg_path1% -i "%file%" -ss 00:00:07 -to %end_time% -c:v copy -c:a copy "trimmed\%file%"

echo Trimming %file% from 00:03:00 to %end_time%
%ffmpeg_path1% -i "%file%" -ss 00:00:03 -to %end_time% -c:v copy -c:a copy "trimmed\%file%"

videoAI wrote what was all wrong with posted batch script, (most likely there was nothing wrong with it) and unfortunately took away "pause" command from the end of script. That part causes cmd prompt to freeze, if there was an error (or not), so you can actually read what went wrong.

Adding pause to videoAI's batch file did not work.
It did not pause.

In regards to the OP's questions.
I do not see how removing a set amounts off the beginning & end will be correct for all 700 files.
I had to make individual settings for the test file I was working with.
At least to get it where I believe it should be.

Let's say I have ten .mp4 files that vary in length. I want to remove the first 30 and the last 10 seconds from each of them

If I remove 30 seconds off the beginning & 10 off the end of the test file I used.
The beginning would be missing too much & the end not enough.
Much less for 10 or 700 files
I do not believe there is a one size fits all solution.

Unless a batch script can be written that detects & removes "no Audio" & "no Video" from the beginning.
Then the same for the end.

[davexnet]

If the source is typical consumer video with temporal compression (log GOP) at least the start cut point will not be
accurate, unless the ffmpeg video "copy" is doing some kind of "smart" rendering (just re-encode the initial GOP) - and I don't think it is.