AR: add compile-time flag for "Automatic Gain Control" option

Automatic Gain Control is a very important aspect of the audioreactive plugin,
and is vitally important when the external music volume constantly changes.

It makes sense to allow users to choose their preferred AGC behavior at
compile-time, since they can already set the Gain and Squelch via flags.

Adds `SR_AGC` as a flag, which defaults to 0 (off).

Author: Arcitec

usermods/audioreactive/audio_reactive.cpp

@@ -65,11 +65,14 @@ static bool udpSyncConnected = false;         // UDP connection status -> true i
 
 // audioreactive variables
 #ifdef ARDUINO_ARCH_ESP32
+    #ifndef SR_AGC // Automatic gain control mode
+    #define SR_AGC 0 // default mode = off
+    #endif
 static float    micDataReal = 0.0f;             // MicIn data with full 24bit resolution - lowest 8bit after decimal point
 static float    multAgc = 1.0f;                 // sample * multAgc = sampleAgc. Our AGC multiplier
 static float    sampleAvg = 0.0f;               // Smoothed Average sample - sampleAvg < 1 means "quiet" (simple noise gate)
 static float    sampleAgc = 0.0f;               // Smoothed AGC sample
-static uint8_t  soundAgc = 0;                   // Automagic gain control: 0 - none, 1 - normal, 2 - vivid, 3 - lazy (config value)
+static uint8_t  soundAgc = SR_AGC;              // Automatic gain control: 0 - off, 1 - normal, 2 - vivid, 3 - lazy (config value)
 #endif
 //static float    volumeSmth = 0.0f;              // either sampleAvg or sampleAgc depending on soundAgc; smoothed sample
 static float FFT_MajorPeak = 1.0f;              // FFT: strongest (peak) frequency

usermods/audioreactive/readme.md

@@ -60,8 +60,9 @@ You can use the following additional flags in your `build_flags`
 
 * `-D SR_SQUELCH=x`  : Default "squelch" setting (10)
 * `-D SR_GAIN=x`     : Default "gain" setting (60)
+* `-D SR_AGC=x`      : (Only ESP32) Default "AGC (Automatic Gain Control)" setting (0): 0=off, 1=normal, 2=vivid, 3=lazy
 * `-D I2S_USE_RIGHT_CHANNEL`: Use RIGHT instead of LEFT channel (not recommended unless you strictly need this).
-* `-D I2S_USE_16BIT_SAMPLES`: Use 16bit instead of 32bit for internal sample buffers. Reduces sampling quality, but frees some RAM ressources (not recommended unless you absolutely need this).
+* `-D I2S_USE_16BIT_SAMPLES`: Use 16bit instead of 32bit for internal sample buffers. Reduces sampling quality, but frees some RAM resources (not recommended unless you absolutely need this).
 * `-D I2S_GRAB_ADC1_COMPLETELY`: Experimental: continuously sample analog ADC microphone. Only effective on ESP32. WARNING this *will* cause conflicts(lock-up) with any analogRead() call.
 * `-D MIC_LOGGER`     : (debugging) Logs samples from the microphone to serial USB. Use with serial plotter (Arduino IDE)
 * `-D SR_DEBUG`       : (debugging) Additional error diagnostics and debug info on serial USB.