First Version

thumbnail.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+inputfile=$1
+mode=$2
+setting=$3
+tile=$4
+
+if [ ! -f "$inputfile" ]
+then
+    echo "$(tput setaf 1)no input file$(tput sgr0)"
+    exit 1
+fi
+outputfile=${inputfile%.*}.jpg # without file type
+if [ -z "$tile" ]
+then
+    tile="3x3"
+fi
+
+if [ "$mode" == "best" ]
+then
+    if [ -z "$setting" ] || (( $setting < 50 ))
+    then
+        setting="800"
+        echo "$(tput setaf 2)using default number of frames to analyse: $(tput setaf 3)$setting$(tput sgr0)"
+    fi
+    ffmpeg -y -i $inputfile -vsync 0 -vf  "thumbnail=$setting,tile=$tile" -frames:v 1 $outputfile
+
+elif [ "$mode" == "fast" ]
+then
+    if [ -z "$setting" ] || (( $setting < 1 ))
+    then
+        setting="120" #min seconds between keyframes
+        echo "$(tput setaf 2)using default seconds between keyframes: $(tput setaf 3)$setting$(tput sgr0)"
+    fi
+    ffmpeg -y -i $inputfile -vsync 0 -vf select="eq(pict_type\,I)*(isnan(prev_selected_t)+gte(t-prev_selected_t\,$setting))",tile=$tile -frames:v 1  $outputfile
+else
+
+    echo "$(tput setaf 1)invalid mode$(tput sgr0)"
+    echo "use \"best\" or \"fast\""
+    exit 1
+fi