ffmpeg script for merging multiple files into one mp4 file

ffmpeg-merge.sh

#!/bin/bash
input_file_find_pattern="'\./$1.*'"
find_command="find . -regex $input_file_find_pattern"

input_files=()
while IFS= read -r line; do
    input_files+=( "$line" )
done  < <( eval $find_command )

ffmpeg_merge_command='ffmpeg -loglevel error'

for (( i = 0; i < ${#input_files[@]}; i++ )); do
	ffmpeg_merge_command+=" -i '${input_files[$i]}'"
done

ffmpeg_merge_command+=" -strict -2 -codec copy '$1.mp4'"

echo "Running ffmpeg command:"
echo $ffmpeg_merge_command

eval $ffmpeg_merge_command