Memory Spikes and Playback Stutters

[lerxstrulz]

Hey All,

I've been trying to diagnose an issue whereby the Max Processor Usage (see code) suddenly spikes and a loop I have playing from SD will stutter for a second. This cycle continues at a seemingly random interval (spike, stutter, drop to normal, spike, stutter....)

I am playing a 1 minute loop .WAV file and restarting it after it ends. I have tried different SD cards, different AudioMemory values...nothing seems to affect it. I noticed this in a different sketch, so I put together the basic one below to start from a base to diagnose, and it's happening even with this very simple sketch.

The output below is written every 1 second. This spike does not happen often...it could be anywhere from 3 to around 10 minutes between occurrences.




Here is the code I am testing with:

#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>

// GUItool: begin automatically generated code
AudioPlaySdWav           loopPlayer;     //xy=383,257
AudioOutputI2S           i2s2;           //xy=559,260
AudioConnection          patchCord1(loopPlayer, 0, i2s2, 0);
AudioControlSGTL5000     audioShield;    //xy=113,275
// GUItool: end automatically generated code

elapsedMillis loopMillis;
unsigned long len = 0;

void setup() {
  Serial.begin(57600);
  
  delay(250);

  // Always allocate memory for the audio shield!
  AudioMemory(4);
  
  // turn on audio shield
  audioShield.enable();

  // turn on post processing
  audioShield.audioPostProcessorEnable();

  // Check SD card
  SPI.setMOSI(7);  // Set to 7 for Teensy
  SPI.setSCK(14);  // Set to 14 for Teensy
  // CS Pin is 10..do not change for Teensy!
  if (!(SD.begin(10))) {
     Serial.println("Unable to access the SD card");
  }

  delay(250);

  loopPlayer.play("/loops/breath.wav");
  delay(10);
  len = loopPlayer.lengthMillis();
  loopMillis = 0;

}

elapsedMillis timer;

void loop() {
  // put your main code here, to run repeatedly:
  if (timer >= 1000) {
    timer = 0;
    showMemory();
  }

  if (loopMillis >= len) {
    loopMillis = 0;
    loopPlayer.play("/loops/breath.wav");
    delay(10);
    len = loopPlayer.lengthMillis();
  }

}

void showMemory() {
    Serial.println("");
    Serial.print("Proc = ");
    Serial.print(AudioProcessorUsage());
    Serial.print(" (");    
    Serial.print(AudioProcessorUsageMax());
    Serial.print("),  Mem = ");
    Serial.print(AudioMemoryUsage());
    Serial.print(" (");    
    Serial.print(AudioMemoryUsageMax());
    Serial.print(") ");
    Serial.print("Free Mem: ");
    Serial.println(freeMemory());
    Serial.println("");
}

#ifdef __arm__
// should use uinstd.h to define sbrk but Due causes a conflict
extern "C" char* sbrk(int incr);
#else  // __ARM__
extern char *__brkval;
#endif  // __arm__
 
int freeMemory() {
  char top;
#ifdef __arm__
  return &top - reinterpret_cast<char*>(sbrk(0));
#elif defined(CORE_TEENSY) || (ARDUINO > 103 && ARDUINO != 151)
  return &top - __brkval;
#else  // __arm__
  return __brkval ? &top - __brkval : &top - __malloc_heap_start;
#endif  // __arm__
}
// END

Also I am using Teensyduino 1.42 with Arduino 1.8.5, Teensy 3.2 and Mac OSX Sierra 10.12.6.

Any ideas?

Thank you!

 

[lerxstrulz]

**** moving to technical support forum ****

 

[defragster]

https://forum.pjrc.com/threads/53136-Teensy-3-2-Audio-Adapter-Memory-Spikes-and-Playback-Stutters