Restore video creation date after it has been stripped by e.g. Google-Photos or ffmpeg

correct_video_date.sh

#!/bin/bash
set -o nounset
directory_original=./keep/conv35veryslow

for filepath in ${directory_original}/*; do
    # echo $filepath
    if (echo $filepath | grep -P 'VID_20\d{6}_\d{6}[^\d]' > /dev/null); then
        # echo "FORMAT1 VID_YYYYMMDD_hhmmss"
        partial_filename=$(echo -n $filepath | sed 's#.*VID_##g')
        YYYY="${partial_filename:0:4}"
        MM="${partial_filename:4:2}"
        DD="${partial_filename:6:2}"
        hh="${partial_filename:9:2}"
        mm="${partial_filename:11:2}"
        ss="${partial_filename:13:2}"
        # echo date is $YYYY-$MM-$DD   $hh-$mm-$ss
    elif (echo $filepath | grep -P 'VID_20\d{6}_\d{9}[^\d]' > /dev/null); then
        # echo "FORMAT2 VID_YYYYMMDD_hhmmss???"
        partial_filename=$(echo -n $filepath | sed 's#.*VID_##g')
        YYYY="${partial_filename:0:4}"
        MM="${partial_filename:4:2}"
        DD="${partial_filename:6:2}"
        hh="${partial_filename:9:2}"
        mm="${partial_filename:11:2}"
        ss="${partial_filename:13:2}"
        # echo date is $YYYY-$MM-$DD   $hh-$mm-$ss
    elif (echo $filepath | grep -P 'VID20\d{12}[^\d]' > /dev/null); then
        # echo "FORMAT3 VIDYYYYMMDDhhmmss"
        partial_filename=$(echo -n $filepath | sed 's#.*VID##g')
        YYYY="${partial_filename:0:4}"
        MM="${partial_filename:4:2}"
        DD="${partial_filename:6:2}"
        hh="${partial_filename:8:2}"
        mm="${partial_filename:10:2}"
        ss="${partial_filename:12:2}"
        # echo date is $YYYY-$MM-$DD   $hh-$mm-$ss
    elif (echo $filepath | grep -P 'Record_\d{4}-\d{2}-\d{2}-\d{2}-\d{2}-\d{2}[^\d]' > /dev/null); then
        # echo "FORMAT4 Record_YYYY-MM-DD-hh-mm-ss"
        partial_filename=$(echo -n $filepath | sed 's#.*/Record_##g')
        YYYY="${partial_filename:0:4}"
        MM="${partial_filename:5:2}"
        DD="${partial_filename:8:2}"
        hh="${partial_filename:11:2}"
        mm="${partial_filename:14:2}"
        ss="${partial_filename:17:2}"
        # echo date is $YYYY-$MM-$DD   $hh-$mm-$ss
    else
        echo "ERROR: NO FORMAT DETECTED: $filepath"
        exit 1
    fi
    (set -x && TZ=UTC touch -a -m -t "$YYYY$MM$DD$hh$mm.$ss" $filepath)
    
done