Edit: 2016-08-02

I found a simpler, built-in in ffmpeg aproach to split a sound/video file in multiple parts with the same time length.

ffmpeg -i 'input_file.mp3' \
       -acodec copy -vcodec copy \
       -f segment -segment_time 600 \
       '%03d_out_name.mp3'

In this example we have an input file called input_file.mp3 and we break it in multiple files of 10 minutes each (600 seconds). Each output file has a unique name of the form: XXX_out_name.mp3 where XXX represents a 3 digit number.

As a reference, the old article:

The present article describes how to split a video/sound into multiple files of same duration using ffmpeg. Click to download automated bash script.

With ffmpeg, to copy just a fraction of a sound (.mp3, .wma, .aac, …) or video file (.mp4, .wma, …) use:

ffmpeg -i "$name" -acodec copy -vcodec copy -t $splitLen -ss $start "$new_name"

where $name is the name of the file to split, $splitLen is the length in seconds of the split, $start the second in which the splitting start and the $new_name for the file.

The idea is to copy fractions of the song (or video) in pieces of the same size, so that adding all the pieces we get the original song (video). Here a bash function that does the job:

splitVideo() {
    # name file to split
    name="$1"
    # splitting time in seconds
    splitLen=$2

    # total of the song
    totalTime="$(ffprobe -i "$name" -show_format 2> /dev/null | sed -n 's/duration=//p')"
    # number of splits required
    numOfSplits="$(printf '%.0f\n' $[ totalTime / splitLen ])"

    for i in {0..$numOfSplits}; do
        start=$[ splitLen * i ]

        num=$(printf '%02d' $[i+1])
        new_name="${name%.*}_${num}.${name//*.}"

        ffmpeg -i "$name" -acodec copy -vcodec copy \
               -t $splitLen -ss $start \
               -metadata "track=$[i+1]" \
               "$new_name"
    done
}

Mode of use: splitVideo "$name_of_the_file" $time_in_seconds, where $time_in_seconds is the size of the split in seconds, for example, if you put 600 it means 10 minutes.

Here’s the bash script. It is the same code as in the bash function, just in a bash file ;)