RMS from "MP3" "I2S" pipeline

[shabtronic]

Hi Folks

I'm sure someone has done this already - whats the easiest way to get a RMS reading from a "MP3" "I2S" pipeline? (or flac)

thanks in advance

Shabby

[shabtronic]

Ok I finally managed to do this and pass the knowledge on!
I cannibalized what equilizer.c does, hopefully there's a easier way to put in a DSP process function and still have the audio pass onto the I2S output stream?

Code: Select all

short DspBuf[4096];
audio_element_info_t Dsp_info = { 0 };
static esp_err_t Dsp_open(audio_element_handle_t self)
	{
	audio_element_getinfo(self, &Dsp_info);	
	return ESP_OK;
	}

static esp_err_t Dsp_close(audio_element_handle_t self)
	{
	return ESP_OK;
	}

audio_element_err_t Dsp_read(audio_element_handle_t el, char *buf, int len, unsigned int wait_time, void *ctx)
	{
	return (audio_element_err_t)len;
	}

audio_element_err_t Dsp_write(audio_element_handle_t el, char *buf, int len, unsigned int wait_time, void *ctx)
	{
	return (audio_element_err_t)len;
	}


static audio_element_err_t Dsp_process(audio_element_handle_t self, char *inbuf, int len)
	{
	audio_element_input(self, (char *)DspBuf, len);
	int ret = audio_element_output(self, (char *)DspBuf, len);
	return (audio_element_err_t)ret;
	}
static esp_err_t Dsp_destroy(audio_element_handle_t self)
	{
	return ESP_OK;
	}

audio_element_cfg_t DspCfg;// = DEFAULT_AUDIO_ELEMENT_CONFIG();
	memset(&DspCfg, 0, sizeof(audio_element_cfg_t));
	DspCfg.destroy = Dsp_destroy;
	DspCfg.process = Dsp_process;
	DspCfg.read = Dsp_read; // why are these needed if they are not called?
	DspCfg.write = Dsp_write; // why are these needed if they are not called?
	DspCfg.open = Dsp_open;
	DspCfg.close = Dsp_close;
	DspCfg.buffer_len = (1024);
	DspCfg.tag = "Dsp";
	DspCfg.task_stack = (2 * 1024);
	DspCfg.task_prio = (5);
	DspCfg.task_core = (0); // core 1 has FPU issues lol
	DspCfg.out_rb_size = (8 * 1024);

	DspProcessor = audio_element_init(&DspCfg);
	audio_pipeline_register(pipeline, DspProcessor, "DspProcessor");

and then plop it into the audio pipeline:

Code: Select all

const char * boomer[]{ "mp3Decoder","DspProcessor", "i2s" };
audio_pipeline_relink(pipeline, boomer, 3);
audio_pipeline_set_listener(pipeline, evt);