stuff/transcode

#!/bin/bash

# Consider this script a collection of ffmpeg settings for video transcoding.
# It doesn't make much sense to share this.
# It's grown from my very personal transcoding needs, it WILL require adjustment.

vcodec=x265 # x265 or x264
# all bitrates in kbps !!!
bitrate=1500 # visually lossless for x265, 1280x720px
preset=medium # the default
delay=600
acodec=copy
noopts=""
speak=0

usage() {
[ -n "$1" ] && echo "
$1"
echo "
Transcodes a list of video files with ffmpeg. Uses a 2-pass algorithm. Most
energy went into the x265 version, but the x264 version also yields good
results! Audio tracks are not transcoded, just copied.
If mediainfo is installed you get some extra statistics at the end.

Options:

  -b int  video bitrate in kilobits per second, just the number (default: $bitrate)

  -v str  video codec (x265|x264) (default: $vcodec)

  -a str  audio codec (default: $acodec) - pass \"default\" to let ffmpeg decide.

  -p str  preset to pass - possible values: ultrafast, superfast, veryfast,
          faster, fast, medium, slow, slower, veryslow

  -n      do not use the hardcoded string of video encoding options

  -d int  delay between completely transcoding files in seconds (default: $delay)

  -s      say something when transcoding is finished. Requires espeak.

There's little quality control, please take care what you pass on the command
line.
"
exit 1
}
# internal, don't change
notify=0

sep="\n###############################################################################\n"

while getopts "b:d:p:v:a:ns" opt; do
  case $opt in
    b) # bitrate
      [[ "$OPTARG" =~ ^[0-9]+$ ]] && [ "$OPTARG" -ge 1 ] || usage "-$opt: Invalid bitrate: $OPTARG (must be a positive integer)"
      bitrate="$OPTARG"
      ;;
    v) # vcodec
      vcodec="$OPTARG"
      ;;
    a) # acodec
      acodec="$OPTARG"
      ;;
    p) # preset
      preset="$OPTARG"
      ;;
    n) # no options
      noopts=".noopts"
      ;;
    d) # delay
      [[ "$OPTARG" =~ ^[0-9]+$ ]] && [ "$OPTARG" -ge 0 ] || usage "-$opt: Invalid delay time: $OPTARG (must be a positive integer)"
      delay="$OPTARG"
      ;;
    s) # use espeak
      speak=1
      ;;
    *) usage
      ;;
  esac
done
shift $((OPTIND-1))

#~ echo "$@
#~ bitrate: $bitrate
#~ delay: $delay
#~ vcodec: $vcodec
#~ preset: $preset"

#~ exit

ffmpeg_cmd="ffmpeg -nostdin -hide_banner -analyzeduration 2147483647 -probesize 2147483647"
endopts="-max_muxing_queue_size 9999"
# about -max_muxing_queue_size: stackoverflow.com/a/56681096
# about -nostdin: stackoverflow.com/a/14866487

[[ "$acodec" == "default" ]] && audio_opts="" || audio_opts="-c:a $acodec"

printf "Files to transcode: $@\nChosen bitrate: ${bitrate}k\nChosen codec: $vcodec\nChosen preset: $preset\n"
counter=0
for file in "$@"; do
    [ -r "$file" ] || continue

    duration="$(mediainfo --Output="Video;%Duration%" "$file")"
    duration="${duration%.*}"
    duration="${duration::-3}"

    outfile="${file%.*} video-$vcodec.bitrate-${bitrate}k.preset-$preset${noopts} acodec-${acodec}.mkv"
    if [ -r "$outfile" ]; then
        mv "$outfile" "${outfile%.*}.$(date +%s).${outfile##*.}" || exit 1
    fi

    start="$SECONDS"

    case "$vcodec" in
    x264)
        if [[ "$noopts" == ".noopts" ]]; then
            x264opts=""
        else
            x264opts="-x264opts frameref=15:fast_pskip=0"
        fi
        printf "${sep}Command first pass:\nffmpeg -y -i $file -an -c:v libx264 -pass 1 -preset $preset $bitrate_opts $x264opts -f rawvideo /dev/null$sep"
        $ffmpeg_cmd -y -i "$file" -an -c:v libx264 -pass 1 -preset "$preset" $bitrate_opts $x264opts $endopts -f rawvideo /dev/null && \
        printf "${sep}Command second pass:\nffmpeg -i $file $audio_opts -c:v libx264 -pass 2 -preset $preset -b:v $bitratek $x264opts $endopts $outfile$sep" && \
        $ffmpeg_cmd -i "$file" $audio_opts -c:v libx264 -pass 2 -preset $preset -b:v "$bitrate"k $x264opts $endopts "$outfile" && \
        notify=1 && rm ffmpeg2pass*.log*
        ;;
    x265)
        params=":vbv-bufsize=1000:vbv-maxrate=$bitrate"
        if [[ "$noopts" != ".noopts" ]]; then
            # see forum.doom9.org/showthread.php?t=172458 for a nice long explain about x265 params.
            params=":ctu=32:max-tu-size=16:crf=20.0:tu-intra-depth=2:tu-inter-depth=2:rdpenalty=2:me=3:subme=5:merange=44:b-intra=1:amp=0:ref=5:weightb=1:keyint=360:min-keyint=1:bframes=8:aq-mode=1:aq-strength=1.0:rd=5:psy-rd=1.5:psy-rdoq=5.0:rdoq-level=1:sao=0:open-gop=0:rc-lookahead=80:scenecut=40:max-merge=4:qcomp=0.8:strong-intra-smoothing=0:deblock=-2:qg-size=16:pbratio=1.2$params"
        fi
        printf "${sep}Command first pass:\nffmpeg -y -i $file -an -c:v libx265 -preset $preset -x265-params pass=1$params -f matroska /dev/null$sep"
        $ffmpeg_cmd -y -i "$file" -an -c:v libx265 -preset "$preset" -x265-params "pass=1$params" $endopts -f matroska /dev/null && \
        printf "${sep}Command second pass:\nffmpeg -i $file $audio_opts -c:v libx265 -preset $preset -x265-params pass=2$params $outfile$sep" && \
        $ffmpeg_cmd -i "$file" $audio_opts -c:v libx265 -preset $preset -x265-params "pass=2$params" $endopts "$outfile" && \
        notify=1 && rm x265_2pass.log*
        ;;
    *)
        echo "Invalid video codec $vcodec"
        exit 1
        ;;
    esac


    end="$SECONDS"
    [[ "$notify" == 1 ]] && printf "$sep\nTranscoding %s (duration: %ds) took %ds in two passes.\nThat is %ds per one second of video.\nThe output file is smaller than the original by a factor of %d\n" "$outfile" "$duration" "$((end - start))" "$(( (end - start) / duration ))" "$(( $(du -b "$file" | cut -f1 ) / $(du -b "$outfile" | cut -f1 ) ))"

    # if this isn't the last file, give the CPU time to cool down between transcoding
    ((++counter<$#)) && sleep $delay

done

if [[ "$notify" == 1 ]]; then
    [[ "$speak" == 1 ]] && espeak "${0##*/}. Finished."
    notify-send -t 0 "${0##*/}" "Finished."
fi