/* MixStereoToMono Created: Chip Audette, Jan 2017 Purpose: Process audio mixing the Left and Right inputs into Mono. Demonstrates audio processing using floating point data type. Uses Teensy Audio Adapter. Assumes microphones (or whatever) are attached to the LINE IN (stereo) MIT License. use at your own risk. */ //These are the includes from the Teensy Audio Library #include //Teensy Audio Librarya #include #include #include #include #include //for AudioConvert_I16toF32, AudioConvert_F32toI16, and AudioEffectGain_F32 //create audio library objects for handling the audio AudioControlSGTL5000_Extended sgtl5000; //controller for the Teensy Audio Board AudioInputI2S i2s_in; //Digital audio *from* the Teensy Audio Board ADC. Sends Int16. Stereo. AudioConvert_I16toF32 int2Float1, int2Float2; //Converts Int16 to Float. See class in AudioStream_F32.h AudioMixer4_F32 mixer; //mix floating point data AudioConvert_F32toI16 float2Int1, float2Int2; //Converts Float to Int16. See class in AudioStream_F32.h AudioOutputI2S i2s_out; //Digital audio *to* the Teensy Audio Board DAC. Expects Int16. Stereo //Do you want to use the USB audio as your input, or do you want to use i2s as your input? #define DO_USB 0 //set to 1 to enable USB audio. Be sure to go under the "Tools" menu and do "USB Type" -> "Audio" #if DO_USB AudioInputUSB usb_in; AudioConnection patchCord1(usb_in, 0, int2Float1, 0); AudioConnection patchCord2(usb_in, 1, int2Float2, 0); #else AudioConnection patchCord1(i2s_in, 0, int2Float1, 0); //connect the Left input to the Left Int->Float converter AudioConnection patchCord2(i2s_in, 1, int2Float2, 0); //connect the Right input to the Right Int->Float converter #endif AudioConnection_F32 patchCord10(int2Float1, 0, mixer, 0); //Left. makes Float connections between objects AudioConnection_F32 patchCord11(int2Float2, 0, mixer, 1); //Right. makes Float connections between objects AudioConnection_F32 patchCord12(mixer, 0, float2Int1, 0); //Left. makes Float connections between objects AudioConnection_F32 patchCord13(mixer, 0, float2Int2, 0); //Right. makes Float connections between objects //For output, you always need an i2s or else you have no clock to drive the audio subsystem. //So, even if you're not going to use the headphone/line-out, you need these lines AudioConnection patchCord20(float2Int1, 0, i2s_out, 0); //connect the Left float processor to the Left output AudioConnection patchCord21(float2Int2, 0, i2s_out, 1); //connect the Right float processor to the Right output //Now, if you want USB output, it gets enabled here #if DO_USB AudioOutputUSB usb_out; AudioConnection patchCord30(float2Int1, 0, usb_out, 0); //connect the Left float processor to the Left output AudioConnection patchCord31(float2Int2, 0, usb_out, 1); //connect the Right float processor to the Right output #endif // which input on the audio shield will be used? const int myInput = AUDIO_INPUT_LINEIN; //const int myInput = AUDIO_INPUT_MIC; //define a function to setup the Teensy Audio Board how I like it void setupMyAudioBoard(void) { sgtl5000.enable(); //start the audio board sgtl5000.inputSelect(myInput); //choose line-in or mic-in sgtl5000.volume(0.8); //volume can be 0.0 to 1.0. 0.5 seems to be the usual default. sgtl5000.lineInLevel(10,10); //level can be 0 to 15. 5 is the Teensy Audio Library's default sgtl5000.adcHighPassFilterDisable(); //reduces noise. https://forum.pjrc.com/threads/27215-24-bit-audio-boards?p=78831&viewfull=1#post78831 sgtl5000.micBiasEnable(3.0); //enable the mic bias voltage...only in AudioControlSGTL5000_Extended } // define the overall setup() function, the function that is called once when the device is booting void setup() { Serial.begin(115200); //open the USB serial link to enable debugging messages delay(500); //give the computer's USB serial system a moment to catch up. Serial.println("Teensy Hearing Aid: BasicCompressor_Float..."); //identify myself over the USB serial // Audio connections require memory, and the record queue // uses this memory to buffer incoming audio. AudioMemory(12); //allocate Int16 audio data blocks AudioMemory_F32(10); //allocate Float32 audio data blocks // Enable the audio shield, select input, and enable output setupMyAudioBoard(); // set the gains on the mixer mixer.gain(0,0.5); //set gain to 0.5 (instead of 1.0) so that the mixer will never clip due to my two-channel mix mixer.gain(1,0.5); //set gain to 0.5 (instead of 1.0) so that the mixer will never clip due to my two-channel mix } //end setup() // define the loop() function, the function that is repeated over and over for the life of the device unsigned long curTime_millis = 0; unsigned long lastMemUpdate_millis=0; void loop() { //print status information to the Serial port curTime_millis = millis(); //what time is it right now if ((curTime_millis - lastMemUpdate_millis) < 0) lastMemUpdate_millis=0; //handle case where millis wraps around! if ((curTime_millis - lastMemUpdate_millis) > 2000) { // print a summary of the current & maximum usage printCPUandMemoryUsage(&Serial); lastMemUpdate_millis = curTime_millis; //we will use this value the next time around. } } //end loop(); void printCPUandMemoryUsage(Stream *s) { s->print("Usage/Max: "); s->print("mixer CPU = "); s->print(mixer.processorUsage()); s->print("/"); s->print(mixer.processorUsageMax());s->print(", "); s->print("all CPU = " ); s->print(AudioProcessorUsage()); s->print("/"); s->print(AudioProcessorUsageMax());s->print(", "); s->print("Int16 Mem = ");s->print(AudioMemoryUsage()); s->print("/"); s->print(AudioMemoryUsageMax());s->print(", "); s->print("Float Mem = ");s->print(AudioMemoryUsage_F32());s->print("/"); s->print(AudioMemoryUsageMax_F32()); s->print(", "); s->println(); };