extract video from command line

extract-video

#!/bin/bash
set -eu -o pipefail
safe_source () { [[ ! -z ${1:-} ]] && source $1; _dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"; _sdir=$(dirname "$(readlink -f "$0")"); }; safe_source
# end of bash boilerplate


# show help
# -----------------------------------------------
show_help(){
    cat <<HELP
    $(basename $0) [options] /path/to/source /path/to/destination
    Options:
        --from          : Starting time, in "00:05:32" format
        duration: (optional)
            --length    : Duration, in "00:2:22" format
            --to        : End time, in "00:3:05" format
        --out       : (optional) Output file name
HELP
    exit
}


# Parse command line arguments
# ---------------------------
# Initialize parameters
_from="0"
_length=
_to=
_out=
# ---------------------------
args=("$@")
_count=1
while :; do
    key="${1:-}"
    case $key in
        -h|-\?|--help|'')
            show_help    # Display a usage synopsis.
            exit
            ;;
        # --------------------------------------------------------
        --from) shift
            _from="$1"
            shift
            ;;
        --length) shift
            _length="$1"
            shift
            ;;
        --to) shift
            _to="$1"
            shift
            ;;
        --out) shift
            _out="$1"
            shift
            ;;
        # --------------------------------------------------------
        -*) # Handle unrecognized options
            echo
            echo "Unknown option: $1"
            show_help
            exit 1
            ;;
        *)  # Generate the positional arguments: $_arg1, $_arg2, ...
            [[ ! -z ${1:-} ]] && declare _arg$((_count++))="$1" && shift
    esac
    [[ -z ${1:-} ]] && break
done; set -- "${args[@]}"
# use $_arg1 in place of $1, $_arg2 in place of $2 and so on, "$@" is intact

[[ -z "$_length" ]] || _length="-t $_length"
[[ -z "$_to" ]] || _to="-to $_to"

input="$_arg1"
out="${_out:-"${input%.*}-${_from}${_to}${_length}.${input##*.}"}"
out="${out//:/_}"

#echo "from: $_from"
#echo "to: $_length"
#echo "input: $input"
echo "output: $out"

ffmpeg -ss "$_from" $_length $_to -i "$input" \
    -vcodec copy -acodec copy "$out"