Print video creation time of MP4 files

ff_show_timestamp.sh

#!/usr/bin/env bash

set -euo pipefail

readonly TIME_ZONE="${TIME_ZONE:-America/Los_Angeles}"

function main() {
  local file="$1"
  local timestamp
  timestamp="$(extract_timestamp "$file")"
  env TZ="$TIME_ZONE" gdate -Is --date "$timestamp"
}

function extract_timestamp() {
  local file="$1"
  ffprobe_json "$file" | jq_extract_timestamp
}

function ffprobe_json() {
  local file="$1"
  ffprobe -v quiet -print_format json -show_format -show_streams "$file"
}

function jq_extract_timestamp() {
  jq -r '.format.tags.creation_time'
}

main "$@"