Bash script to use ffmpeg to pad an input with a color and silence at one or both ends.

padmovie

#!/bin/bash

# suffix to use on the output file
suffix="_padded"
# color must be a value from http://ffmpeg.org/ffmpeg-utils.html#Color
color="black"
# seconds_at_start must be an integer
seconds_at_start=2
# seconds_at_end must be an integer
seconds_at_end=10

get_width(){
    width=$(ffprobe "$1" -show_streams -select_streams v:0 2> /dev/null | grep ^width= | cut -d = -f 2)
}

get_height(){
    height=$(ffprobe "$1" -show_streams -select_streams v:0 2> /dev/null | grep ^height= | cut -d = -f 2)
}

get_framerate(){
    framerate=$(ffprobe "$1" -show_streams -select_streams v:0 2> /dev/null | grep ^r_frame_rate= | cut -d = -f 2)
    if [ "$framerate" = "2997/100" ] ; then
        framerate="30000/1001"
    fi
}

get_channels(){
    channels=$(ffprobe "$1" -show_streams -select_streams a:0 2> /dev/null | grep ^channels= | cut -d = -f 2)
}

get_sar(){
    unset sar
    sar=$(ffprobe "$1" -show_streams -select_streams v:0 2> /dev/null | grep ^sample_aspect_ratio= | cut -d = -f 2 | sed 's|:|/|g')
    if [ "$sar" = "0/1" ] ; then
        sar="1/1"
    fi
}

get_samplerate(){
    samplerate=$(ffprobe "$1" -select_streams a:0 -show_streams 2> /dev/null | grep ^sample_rate= | cut -d= -f2)
}

get_audiocodecname(){
    audiocodecname=$(ffprobe "$1" -select_streams a:0 -show_streams 2> /dev/null | grep ^codec_name= | cut -d= -f2)
}

get_timecode(){
    unset timecode
    timecode=$(ffprobe "$1" -show_format 2> /dev/null | grep ^TAG:timecode | cut -d= -f2)
    if [ "$timecode" = "" ] ; then
        timecode="01:00:00;00"
    fi
}

adjusttimecode() {
    timecode="${1}"
    h="${timecode:0:2}"
    m="${timecode:3:2}"
    s="${timecode:6:2}"
    d="${timecode:8:1}"
    f="${timecode:9:2}"
    seconds=$(echo "${h}*3600+${m}*60+${s}" | bc)
    adjustedseconds=$(echo "${seconds}-${seconds_at_start}" | bc)
    h2="$((${adjustedseconds}/60/60))"
    m2="$((${adjustedseconds}/60%60))"
    s2="$((${adjustedseconds}%60))"
    echo "${h2}:${m2}:${s2}${d}${f}"
}

if [ "$#" = 0 ] ; then
    echo "this script is intended to simply accept an input video and then add some amount of padded to one or both ends, while adjusting the timecode to maintain timecode-to-frame associations of the input."
    echo "Usage: $(basename ${0}) [ -o output_directory ] file1 [ file2 ... ]"
    echo
    echo "There's some other options but tweak the header of this script to work that."
    exit
fi

# command-line options
OPTIND=1
while getopts ":o:x:" opt ; do
    case "${opt}" in
        o) output_dir="$OPTARG" ;;
        x) audio_offset="$OPTARG" ;;
        *) echo "bad option -$OPTARG" ; usage ;;
        :) echo "Option -$OPTARG requires an argument" ; exit 1 ;;
    esac
done
shift $(( ${OPTIND} - 1 ))

while [ "${*}" != "" ] ; do
    # get context about the input
    input_movie="${1}"
    name=$(basename "$input_movie")
    
    if [ ! -s "$input_movie" ] ; then
       echo Hey "$input_movie" does not look like a real file.
       exit
    fi
    if [ ! -d "$output_dir" ] ; then
       output_dir=`dirname "$input_movie"`
    fi

    if [ ! "$audio_offset" ] ; then
       audio_offset="0"
    fi

    get_timecode "${input_movie}"
    timecodeout=$(adjusttimecode "$timecode")
    echo "timecode is adjusted from $timecode to $timecodeout"

    get_width "${input_movie}"
    get_height "${input_movie}"
    get_framerate "${input_movie}"
    get_channels "${input_movie}"
    get_sar "${input_movie}"
    get_samplerate "${input_movie}"
    get_audiocodecname "${input_movie}"

    ffmpeg -f lavfi -i "color=color=${color}:s=${width}x${height}:r=${framerate}:sar=${sar}:d=${seconds_at_start}" \
        -f lavfi -i "aevalsrc=0:s=${samplerate}:c=${channels}:d=${seconds_at_start}" \
        -i "${input_movie}" \
        -f lavfi -i "color=color=${color}:s=${width}x${height}:r=${framerate}:sar=${sar}:d=${seconds_at_end}" \
        -f lavfi -i "aevalsrc=0:s=${samplerate}:c=${channels}:d=${seconds_at_end}" \
        -filter_complex "[0:v:0][1:a:0][2:v:0][2:a:0][3:v:0][4:a:0]concat=n=3:v=1:a=1[v][a];\
            [a]asetpts=PTS+${audio_offset}/TB[a1]" \
        -map '[v]' -map '[a1]' -shortest -c:v v210 -r:v "${framerate}" -metadata:s:v:0 timecode="${timecodeout}" -metadata:s:v:0 encoder="Uncompressed 10-bit 4:2:2" -c:a "${audiocodecname}" -ac "${channels}" -ar "${samplerate}" -y "$output_dir/${name%.*}${suffix}.mov"

    shift
done