From a2f5be375c0f0f44d9cb869c67c7970f04afdb4a Mon Sep 17 00:00:00 2001
From: tastytea <tastytea@tastytea.de>
Date: Thu, 17 Feb 2022 08:48:03 +0100
Subject: [PATCH] Add apng2webp

---
 README.md    |  1 +
 apng2webp.sh | 42 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)
 create mode 100755 apng2webp.sh

diff --git a/README.md b/README.md
index 8712bde..1c5e3e5 100644
--- a/README.md
+++ b/README.md
@@ -4,3 +4,4 @@
 |       yt2mpd.sh | Adds an Youtube video to MPD, with correct title and duration.               |
 | fetch_gaidao.sh | Auf neue Ausgaben von der Gai Dao prüfen, herunterladen.                     |
 |         srtadrm | Remove ads from SRT files with a list of POSIX extended regular expressions. |
+|    apng2webp.sh | Convert animated PNG to animated WebP                                        |
diff --git a/apng2webp.sh b/apng2webp.sh
new file mode 100755
index 0000000..4b29567
--- /dev/null
+++ b/apng2webp.sh
@@ -0,0 +1,42 @@
+#!/bin/bash
+# Convert animated PNG to animated WebP. Maximum compression no blend.
+
+set -euo pipefail
+
+if [[ $# -lt 2 ]]; then
+    echo "Usage: ${0} input.png output.webp" >&2
+    exit 1
+fi
+input="$(realpath "${1}")"
+output="$(realpath "${2}")"
+
+mkdir -p apng2webp_work
+pushd apng2webp_work
+
+mkdir -p apngdis
+pushd apngdis
+cp "${input}" "input.png"
+apngdis "input.png"
+popd
+
+counter=1
+for file in apngdis/apngframe*.png; do
+    # shellcheck disable=2086
+    cwebp -lossless -q 100 "${file}" -o "$(printf "%02d" ${counter}).webp"
+    counter=$((counter+1))
+done
+
+webpmux_options=""
+counter=1
+for file in apngdis/apngframe*.txt; do
+    delay=$(grep -Po '=\d+/' "${file}")
+    delay="${delay:1:-1}"
+    webpmux_options="${webpmux_options} -frame $(printf "%02d" ${counter}).webp +${delay}+0+0+0-b"
+    counter=$((counter+1))
+done
+
+# shellcheck disable=2086
+webpmux ${webpmux_options} -o "${output}"
+
+popd
+rm -r apng2webp_work