videoenc

#!/bin/sh

error() {
    echo "$@" >&2
    exit 1
}

set_video() {
    local hw

    preset='-preset slow'
    case "$1" in
    copy)
        codec=copy
        hw=0
        ;;
    h264_sw)
        codec=libx264
        hw=0
        ;;
    h264_hw)
        codec=h264_qsv
        hw=1
        ;;
    h265_sw)
        codec=libx265
        tag='-tag:v hvc1' # this is needed by broken devices like Apple ones
        hw=0
        ;;
    h265_hw)
        codec=hevc_qsv
        tag='-tag:v hvc1'
        hw=1
        ;;
    av1_sw)
        codec=libsvtav1
        preset='-preset 6'
        hw=0
        ;;
    av1_hw)
        codec=av1_qsv
        hw=1
        ;;
    *)
        error "Invalid video codec '$1'"
        ;;
    esac

    if [ $hw -eq 1 ]; then
        hwaccel='-hwaccel qsv -hwaccel_output_format qsv'
        # see https://github.com/intel/media-delivery/blob/master/doc/quality.rst
        quality="
            -global_quality $q
            -g 256
            -bf 7
            -extbrc 1
            -look_ahead_depth 40
            -b_strategy 1
            -refs 5
            -adaptive_i 1
            -adaptive_b 1
            -strict -1
        "
    else
        quality="-crf $q"
    fi
}

codec=av1_hw
q=25
getopts=':v:q:h'

usage() {
    cat <<- EOF
        Usage: ${0##*/} [-v codec] [-q quality] <input.avi> <output.[mp4|mkv]>
            video codecs: copy, h264_sw, h264_hw, h265_sw, h265_hw, av1_sw, av1_hw. Default av1_hw
            quality: 1-51 (lower is better). Default 25
    EOF
    exit $1
}

while getopts $getopts arg; do
    case "$arg" in
    v)
        codec=$OPTARG
        ;;
    h)
        usage 0
        ;;
    q)
        q=$OPTARG
        case "$q" in *[!0-9]*) usage 1 ;; esac
        { [ "$q" -lt 1 ] || [ "$q" -gt 51 ] ; } && usage 1
        ;;
    *)
        usage 1
        ;;
    esac

done

shift $((OPTIND - 1))

in=$1
out=$2

[ $# -ne 2 ] && usage 1

[ -f "$in" ] || error "file '$in' not found"

set_video "$codec"

exec ffmpeg -y -loglevel quiet -stats $hwaccel -i "$in" -c:v $codec $preset $quality $tag -c:a copy "$out"