Creating a drag and drop batch file to split an MP3 using ffmpeg

Question

I've got a folder full of FFMPEG batch files that I've written to do various conversion tasks. These allow me to drag and drop a bunch of files and do a conversion - for example, decompressing MP3 to WAV files, cropping XVID files etc.

Now I want to write one that splits an MP3 into smaller chunks. There's a neat FFMPEG command for this

ffmpeg -f mp3 -i /path/to/file.mp3 -t 00:00:00 -ss 00:10:00 -y /path/to/save.mp3

However, this only extracts the first 10 minutes. To go through the whole MP3 I'd have to write similar statements for every 10 minutes of the MP3's length. Is there a way to tokenise this in batch files?

Answer 1

Well, there's two ways to go about this:

1. You can provide the batch file with command line arguments ffchunk.cmd *start* *end* which will give you flexibility in determining the chunk lengths. The batch file would look something like this:

   `ffmpeg -f mp3 -i /path/to/file.mp3 -t 00:%1:00 -ss 00:%2:00 -y
   /path/to/save%1-%2.mp3`
   

   , where the %1 and %2 represent the first and second arguments given at the command line, respectively. You would invoke it as ffchunk 00 10.

2. Provide a loop inside the batch file to iterate as much as you need:

    `@echo off
    setlocal ENABLEEXTENSIONS
    setlocal ENABLEDELAYEDEXPANSION
   
    for /L %%i in (1,1,10) do (
     set /a j=%%i-1
     set k=%%i
     if !j! lss 10 set j=!j!0
     if !k! lss 10 set k=!k!0
     ffmpeg -f mp3 -i /path/to/file.mp3 -t 00:!j!:00 -ss 00:!k!:00 -y /path/to/save!j!-!k!.mp3
    )`
   

Answer 2

You could use ffmpeg's segment muxer. Something like:

ffmpeg -i input.mp3 -map 0 -c copy -f segment -segment_time 600 out-%02d.mp3

...will produce a number of files along the lines of out-00.mp3, out-01.mp3, and so on, each 600 seconds long (except for the final part, which will be the remainder). There are accuracy issues using the segment muxer with videos (though these can be overcome, see the documentation I linked to), but I've never had any problems when working with audio files.