Cutting a video into even segments and using the start and end time of the segment as its filename with FFmpeg and PHP.

For this you will need the length of the video in seconds as a loop is formed to represent each second. You can use the PHP function from here.

By using the Modulo operator the segment length can be determined at even intervals. To have the last segment filename be true to the length of the video in seconds, a check is done.

If the video is 35 seconds long and segment intervals of 10 seconds are wanted:

0-10
10-20
20-30
30-35

Instead of the last iteration misrepresenting the end time (30-40).

Cutting into segments

$time_seconds = 1780;

$segment_length = 30;

for ($i = 0; $i <= $time_seconds; $i++) {
    if ($i % $segment_length === 0) {
        (($i + $segment_length) > $time_seconds) ? $until = $time_seconds : $until = ($i + $segment_length);
        echo "ffmpeg -i input.mp4 -ss $i -t 30 cuts/{$i}-$until.mp4<br>";//Output query for debugging
    }
}

-ss is seek to position and -t is duration to limit the read.

Example output:

ffmpeg -i input.mp4 -ss 0 -t 30 cuts/0-30.mp4
ffmpeg -i input.mp4 -ss 30 -t 30 cuts/30-60.mp4
ffmpeg -i input.mp4 -ss 60 -t 30 cuts/60-90.mp4
ffmpeg -i input.mp4 -ss 90 -t 30 cuts/90-120.mp4
ffmpeg -i input.mp4 -ss 120 -t 30 cuts/120-150.mp4
ffmpeg -i input.mp4 -ss 150 -t 30 cuts/150-180.mp4
ffmpeg -i input.mp4 -ss 180 -t 30 cuts/180-210.mp4
ffmpeg -i input.mp4 -ss 210 -t 30 cuts/210-240.mp4
ffmpeg -i input.mp4 -ss 240 -t 30 cuts/240-270.mp4
....

Finding segments

To find the segment that contains the video at 355 seconds:

$find_segment = 355;//seconds

for ($i = 0; $i <= $time_seconds; $i++) {
    if ($i % $segment_length === 0) {
        if ($find_segment >= $i && $find_segment <= ($i + $segment_length)) {
            $until = $i + $segment_length;
            echo "cuts/{$i}-{$until}.mp4";//cuts/330-360.mp4
        }
    }
}