From 51f1670e8e370eb5589b301b21ae7fb026f2d41f Mon Sep 17 00:00:00 2001
From: Henrik Lissner <henrik@lissner.net>
Date: Wed, 10 May 2017 10:25:11 +0200
Subject: [PATCH] Rewrite bin/mov2gif

---
 bin/mov2gif | 78 ++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 57 insertions(+), 21 deletions(-)

diff --git a/bin/mov2gif b/bin/mov2gif
index 45ed31fa..e25cf9b4 100755
--- a/bin/mov2gif
+++ b/bin/mov2gif
@@ -1,7 +1,55 @@
 #!/usr/bin/env bash
 
-usage() { echo "Usage: $0 [-f <fps>] [-o <output-dest>] [-h]"; }
+# Uses ffmpeg to convert a video file to a gif file. Optimizes the final result
+# with gifsicle.
+#
+# Requires: ffmpeg
+# Optional: gifsicle
+#
+# Example:
+#   vid2gif some-vid.mp4 output.gif
+#   vid2gif -f 10 -s 00:00:10 -t 00:00:05 some-vid.mp4 output.gif
 
+set -e
+PALETTE="/tmp/palette.png"
+
+usage() {
+    cat <<EOL
+Usage: $0 [-fsth] [videofile] [destfile]
+
+    -f [FPS]       set frames per second
+    -s [hh:mm:ss]  set starting time (like -ss in ffmpeg)
+    -t [hh:mm:ss]  set the duration to capture (like -t in ffmpeg)
+    -h             this help
+EOL
+}
+
+cleanup() { rm -f "$PALETTE"; }
+trap cleanup EXIT
+
+#
+fps=30
+while getopts hf:s:t: opt; do
+    case $opt in
+        f) fps="$OPTARG" ;;
+        s) start="-ss $OPTARG" ;;
+        t) duration="-t $OPTARG" ;;
+        h) usage
+            exit
+            ;;
+        :) >&2 echo "$OPTARG requires an argument"
+            usage
+            exit 1
+            ;;
+        *) >&2 echo "Not a valid arg: $opt"
+            usage
+            exit 1
+            ;;
+    esac
+done
+shift $((OPTIND-1))
+
+#
 if (($# == 0)); then
     >&2 echo "No movie file specified"
     exit
@@ -10,27 +58,15 @@ elif [[ ! -f $1 ]]; then
     exit
 fi
 
-fps=30
 src="$1"
-dest="${${src##*/}%.mov}.gif"
-while getopts hf:o: opt; do
-    case $opt in
-        -f) fps="$OPTARG" ;;
-        -o) dest="$OPTARG" ;;
-        -h) usage
-            exit
-            ;;
-        :)  >&2 echo "$OPTARG requires an argument"
-            usage
-            exit 1
-            ;;
-    esac
-done
-
-palette="$(mktemp)"
+dest="${2:-${${src##*/}%.mov}.gif}"
 flags="fps=${fps}"
 
-ffmpeg -v warning -i "$src" -vf "$flags,palettegen" -y "$palette"
-ffmpeg -v warning -i "$src" -i "$palette" -lavfi "$flags [x]; [x][1:v] paletteuse" -y "$dest"
+# stats_mode=full favors motion, causing the resulting palette to better
+# accomodate fades and transitions.
+ffmpeg -v warning $start $duration -i "$src" -vf "$flags,palettegen=stats_mode=full" -y "$PALETTE"
+ffmpeg -v warning $start $duration -i "$src" -i "$PALETTE" -lavfi "$flags [x]; [x][1:v] paletteuse" -y "$dest"
 
-[[ -f $palette ]] && rm -f "$palette"
+if command -v gifsicle >/dev/null; then
+    gifsicle -O3 "$dest" -o "$dest"
+fi