reencode.sh

   1 #!/usr/bin/env bash
   2 # Copyright: Julien Moutinho <julm+camera@sourcephile.fr>
   3 # License: AGPL-3.0-or-later
   4 #
   5
   6 cd "${0%/*}"
   7 set -eu
   8 shopt -s nullglob
   9
  10 ffmpeg_ () { local -; set -x; nice -19 ffmpeg </dev/null -hide_banner -loglevel warning -stats -y "$@"; }
  11 mv_ () { local -; mv -i >&2 "$@"; }
  12 set -x
  13 for dir in "$@"; do
  14   IFS=/ read -r user year x month x <<<"$dir"
  15   test -n "$year" || exec "$0" "$user"/2*/src/*/
  16   test -n "$month" || exec "$0" "$user"/"$year"/src/*/
  17   pushd "$user/$year" >/dev/null
  18   test -d src/"$month" || { popd; continue; }
  19   (cd src; find -L "$month" -type f -size +200M -printf '%f %p\n') | sort -t/ -k1.5 | cut -f2 -d ' ' |
  20   while read -r src; do
  21     echo >&2 "$dir: processing $year/src/$src"
  22     base=${src%.*}
  23     name=${base#*/}
  24     id=${name%%.*}
  25     mkdir -p {tmp,wip,old}/reencode/"${base%/*}"
  26     case "$src" in
  27       *.mp4)
  28         # Slow, but needed to make wide videos span two columns of the CSS grid
  29         orient=$(ffprobe -v 0 -select_streams v:0 -show_entries stream_side_data=rotation -of default=nw=1:nk=1 src/"$src")
  30         psize=720
  31         crf=40
  32         ext="crf=$crf.${psize}p.av1.webm"
  33         if [ -z "$orient" ]; then scale="-2:${psize}"; else scale="${psize}:-2"; fi
  34         need_opus () {
  35           test tmp/reencode/"$base".opus -nt src/"$src" || {
  36             ffmpeg_ -i src/"$src" \
  37               -map 0:a -c:a libopus -b:a 64k -application voip \
  38               wip/reencode/"$base".opus
  39             mv_ {wip,tmp}/reencode/"$base".opus
  40           }
  41         }
  42         test src/"$base.$ext" -nt src/"$src" || {
  43           need_opus
  44           # See https://gitlab.com/AOMediaCodec/SVT-AV1/-/blob/master/Docs/CommonQuestions.md
  45           # See https://gist.github.com/BlueSwordM/86dfcb6ab38a93a524472a0cbe4c4100
  46           # See https://www.streamingmediaglobal.com/Articles/ReadArticle.aspx?ArticleID=154488
  47           # -preset       Range from 0 to 13, with higher numbers providing a higher encoding speed;
  48           # -crf          Range is 0-63, with the default being 50.
  49           #               Lower values correspond to higher quality and greater file size
  50           # yuv420p
  51           # yuv420p10le   can represent more shades of grey and colors
  52           #               and is less prone to certain artifacts, such as color
  53           #               banding and loss of detail in low luma areas,
  54           #               cost in terms of resulting file size (~5%),
  55           #               can also be more compute-intensive than 8-bit in some decoders
  56           # tune=0        subjective mode often results in an image with greater
  57           #               sharpness and is intended to produce a result that appears to humans
  58           #               to be of high quality (as opposed to doing well on basic objective measures,
  59           #               such as PSNR)
  60           # scd=1         biases the encoders' scene detection to insert more intra refreshes if needed,
  61           #               and reduce temporal dependencies around scene-changes.
  62           # scm=0         screen content mode decision making. 0 is best for live-action.
  63           # fast-decode=3 trade compression efficiency for less CPU time when decoding
  64           #               for preset 5-7: levels 1-3 (3 being faster) are supported.
  65           ffmpeg_ -i src/"$src" -i tmp/reencode/"$base".opus \
  66             -map 0:v \
  67               -filter:v format=yuv420p,scale="$scale" \
  68               -c:v libsvtav1 -preset 7 -crf "$crf" \
  69                 -svtav1-params tune=0:enable-overlays=1:scd=1:scm=0:fast-decode=3 \
  70             -map 1:a -c:a copy \
  71             wip/reencode/"$base.$ext"
  72           mv_ {wip/reencode,src}/"$base.$ext"
  73           mv_ {src,old/reencode}/"$src"
  74         }
  75         ;;
  76     esac
  77   done
  78   rm -vrf {tmp,wip}/reencode
  79   popd >/dev/null
  80 done