Add ffmpeg function to convert video to gif

.config/scripts/functions/ffmpeg

@@ -0,0 +1,10 @@
+#!/bin/bash
+function video_to_gif() {
+    if [ "$#" -ne 4 ]; then
+        echo "Usage: video_to_gif input.mp4 output.gif start duration"
+        return 1
+    fi
+    ffmpeg -ss "$3" -t "$4" -i "$1" \
+        -vf "fps=24,scale=480:-1:flags=lanczos,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" \
+        -loop 0 "$2"
+}