Add info about cache and cache_helper.sh script

README.md

@@ -20,6 +20,12 @@ Python dependencies:
 ```pip install -r requirements.txt```
 Optional: brotli
 
+### About cache folder
+funkwhale-cli first to cache tracks before playing. Cache is persistent and You manage manually as is.  
+Cache structure: cache/domain.tld/[track uuid]  
+You can to play tracks offline, example: mpv --shuffle cache/*/*  
+cache_helper.sh - just useful for compression cache (lossy: vorbis 128 kbps, no thumbnail)  
+  
 Also, tnx Inex for his FunkWhale instance (set by default instance)  
 
 [1]**Warning:** may content _unofficial instances_  

cache_helper.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+if [ ! -n "$1" ]; then
+	echo 'Usage: cache_helper.sh path/to/cache'
+	exit 1
+fi
+
+total_before=0
+total_after=0
+for i in "$1"/*/*; do
+	if [ $(ffprobe -hide_banner -print_format json -select_streams a:0 -show_streams "$i" | jq '.streams[0].codec_name') != "vorbis" ]; then
+		size_before=$(stat --format=%s "$i")
+		total_before=$(( $total_before + $size_before ))
+		ffmpeg -hide_banner -loglevel error -i "$i" -vn "$i".ogg
+		if [ $? -eq 0 ]; then
+			size_after=$(stat --format=%s "$i".ogg)
+			total_after=$(( $total_after + $size_after ))
+			echo "before: $(echo $size_before | numfmt --to=iec) | after: $(echo $size_after | numfmt --to=iec)" 
+			mv "$i".ogg "$i"
+		else
+			echo "$i convert failed"
+		fi
+	else
+		echo "$i already compressed good"
+	fi
+done
+
+echo "Total before: $(echo $total_before | numfmt --to=iec)"
+echo "Total after: $(echo $total_after | numfmt --to=iec)"
+echo "Note: only included processed tracks"