Script to stabilize shaky GoPro footage with ffmpeg and libvidstab

gostab.sh

#!/bin/bash

# Run without args to see usage

##### Configuration #####

# Maximum shakiness and accuracy
DETECT_OPTS="shakiness=10:accuracy=15"
# Fish-eye correction for GoPro H3+B 16:9 Wide
# http://stackoverflow.com/questions/30832248/is-there-a-way-to-remove-gopro-fisheye-using-ffmpeg/40659507#40659507
# I can barely see the difference, though :(
PRE_STAGES="lenscorrection=cx=0.5:cy=0.5:k1=-0.227:k2=-0.022"
# Zoom: dynamic/static/no. Dynamic may produce strange results.
# TRANSFORM_OPTS="smoothing=30:zoom=10:optzoom=2:zoomspeed=1:interpol=bicubic"
TRANSFORM_OPTS="smoothing=30:zoom=10:interpol=bicubic"
# TRANSFORM_OPTS="smoothing=30:interpol=bicubic"
# As recommended by vidstab author
POST_STAGES="unsharp=5:5:0.8:3:3:0.4"

# h.264 output options
VOUT_OPTS="-vcodec libx264 -preset slow -tune film -crf 18"

# Compare central regions of two videos side-by-side
SBS_PIPELINE="[0:v] crop=out_w=iw/2:x=iw/4, pad=width=iw*2 [a];[1:v] crop=out_w=iw/2:x=iw/4 [b]; [a][b] overlay=x=W/2"

##### Script support funcs (just skip to the next section) #####

declare -a ACTIONS
declare -a USAGE=("Usage:")

add-action () {
    ACTIONS+=($1)
    USAGE[${#USAGE[@]}]=`echo "   " $BASENAME $@`
}

usage () {
    for ((i = 0; i < ${#USAGE[@]}; i++)); do
        echo "${USAGE[$i]}"
    done
}

main () {
    action=$1
    shift

    if [[ -z "${action// /}" ]]; then
        usage && exit
    fi

    for a in ${ACTIONS[@]}; do
        if [[ $action == $a ]]; then
            $a $@
            exit
        fi
    done

    usage
}

##### Functional part #####

add-action stab-detect "<IN:video> <OUT:vectors> - analyze <video> to calculate transform <vectors>"
function stab-detect () {
    VIDEO="$1"
    VECTORS="$2"
    ffmpeg -i "${VIDEO}" -vf "vidstabdetect=${DETECT_OPTS}:result=${VECTORS}" -f null -
}

add-action stab-transform "<IN:video> <IN:vectors> <OUT:stabilized> - produce <stabilized> version of <video> using transform <vectors>"
function stab-transform () {
    VIDEO="$1"
    VECTORS="$2"
    STABILIZED="$3"
    ffmpeg -i "${VIDEO}" \
        -vf "${PRE_STAGES},vidstabtransform=input=${VECTORS}:${TRANSFORM_OPTS},${POST_STAGES}" \
        ${VOUT_OPTS} -acodec copy "${STABILIZED}"
}

add-action stabilize "<IN:video> <OUT:stabilized> - combined detect and transform"
function stabilize () {
    VIDEO="$1"
    STABILIZED="$2"
    VECTORS="${VIDEO%.*}.trf"
    stab-detect "${VIDEO}" "${VECTORS}" && \
        stab-transform "${VIDEO}" "${VECTORS}" "${STABILIZED}"
}

add-action compare "<IN:video1> <IN:video2> <OUT:output> - make side-by-side comparison video"
function compare () {
    ffmpeg -i "$1" -i "$2" -filter_complex "${SBS_PIPELINE}" ${VOUT_OPTS} "$3"
}

main $@