From 7d416992a578d68f6ff12ec519e9b437d1afbbf3 Mon Sep 17 00:00:00 2001
From: frederik <frederik.slos@gmail.com>
Date: Thu, 18 Jan 2024 15:08:55 +0100
Subject: [PATCH] spectrum: rate limit generating spectrum

---
 scripts/spectrogram.sh | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/scripts/spectrogram.sh b/scripts/spectrogram.sh
index b3aa37a..795d161 100755
--- a/scripts/spectrogram.sh
+++ b/scripts/spectrogram.sh
@@ -12,13 +12,20 @@ if [ "$LOGGING_LEVEL" == "info" ] || [ "$LOGGING_LEVEL" == "debug" ];then
   set -x
 fi
 
+next=0
+looptime=$(( RECORDING_LENGTH * 2 / 3 ))
+
 # Continuously loop generating a spectrogram
 inotifywait -m -e close_write "$HOME/BirdNET-Pi/analyzing_now.txt" |
 while read; do
-  analyzing_now="$(<$HOME/BirdNET-Pi/analyzing_now.txt)"
+  now=$(date +%s)
+  if (( now > next )); then
+    analyzing_now="$(<$HOME/BirdNET-Pi/analyzing_now.txt)"
 
-  if [ -n "${analyzing_now}" ] && [ -f "${analyzing_now}" ]; then
-    spectrogram_png=${EXTRACTED}/spectrogram.png
-    sox -V1 "${analyzing_now}" -n remix 1 rate 24k spectrogram -c "${analyzing_now//$HOME\//}" -o "${spectrogram_png}"
+    if [ -n "${analyzing_now}" ] && [ -f "${analyzing_now}" ]; then
+      spectrogram_png=${EXTRACTED}/spectrogram.png
+      sox -V1 "${analyzing_now}" -n remix 1 rate 24k spectrogram -c "${analyzing_now//$HOME\//}" -o "${spectrogram_png}"
+    fi
+    next=$(( now + looptime ))
   fi
 done