STM32F746 cannot read level of audio input signal

[aciuf]

I would like to read the level of audio input signal to use like a vu-meter instead of use analog input.

This is my code but I read always 0dB on both channels.

void AUDIO_PLAYER_Init2()
{

/* Allocat mem for Smr */

pSmrPersistentMem = malloc(smr_persistent_mem_size); /* smr_persistent_mem_size 0x188 */

pSmrScratchMem = malloc(smr_scratch_mem_size); /* smr_scratch_mem_size 0xF04 */

if (BSP_AUDIO_IN_Init(INPUT_DEVICE_INPUT_LINE_1, 80, AUDIO_FREQUENCY_48K) != 0)

LCD_LOG_SetHeader((uint8_t *)"Audio SMR Application KO");

else

LCD_LOG_SetHeader((uint8_t *)"Audio SMR Application OK");

}

void Audio_Process2()
{

    int32_t error = SMR_ERROR_NONE;

    __HAL_RCC_CRC_CLK_ENABLE();

    CRC->CR = CRC_CR_RESET;

    error = smr_reset(pSmrPersistentMem, pSmrScratchMem);

    if (error != SMR_ERROR_NONE)

    {

        BSP_LCD_DisplayStringAt(10, 20, (uint8_t *)"--err0--", LEFT_MODE);

        return (AUDIO_ERROR_SMR);

    }

    smr_static_param.sampling_rate = 48000; /* only sampling rate supported */

    error = smr_setParam(&smr_static_param, pSmrPersistentMem);

    if (error != SMR_ERROR_NONE)

    {

       BSP_LCD_DisplayStringAt(10, 20, (uint8_t *)"--err1--", LEFT_MODE);

       return (AUDIO_ERROR_SMR);

    }

    smr_dynamic_param.enable = 1; /* SMR module enabler */

    smr_dynamic_param.averaging_time = AUDIO_CFG_SMR_AVGTIME_DEFAULT;

    smr_dynamic_param.filter_type = SMR_PREFILTER_AWEIGHTING;

    error = smr_setConfig(&smr_dynamic_param, pSmrPersistentMem);

    if (error != SMR_ERROR_NONE)

    {

        BSP_LCD_DisplayStringAt(10, 20, (uint8_t *)"--err2--", LEFT_MODE);

       return (AUDIO_ERROR_SMR);

    }

    error = smr_getConfig(&smr_dynamic_param, pSmrPersistentMem);

    if (error != SMR_ERROR_NONE)

    {

       BSP_LCD_DisplayStringAt(10, 20, (uint8_t *)"--err4--", LEFT_MODE);

       return AUDIO_ERROR_SMR;

   }

   BufferHandler.nb_bytes_per_Sample = 2; /* 16-bit */

   BufferHandler.nb_channels = 2; /* stereo */

   BufferHandler.data_ptr = PCM_Data_SMR;

   BufferHandler.buffer_size = 32/2; /* just half buffer is process (size per channel) */

   BufferHandler.mode = INTERLEAVED;

   BufferHandler.data_ptr = &BufferCtl.buff[AUDIO_OUT_BUFFER_SIZE /2];

   error = smr_process(pBufferHandler, pBufferHandler, pSmrPersistentMem);

   if (error != SMR_ERROR_NONE)

  {

     BSP_LCD_DisplayStringAt(10, 20, (uint8_t *)"--err5--", LEFT_MODE);

     return (AUDIO_ERROR_SMR);

  }

   error = smr_getConfig(&smr_dynamic_param, pSmrPersistentMem);

   if (error != SMR_ERROR_NONE)

   {

      BSP_LCD_DisplayStringAt(10, 20, (uint8_t *)"--err6--", LEFT_MODE);

      return AUDIO_ERROR_SMR;

   }

sprintf((char *)str_pwr, "Left mean power: %ld dB",(int32_t)((float)smr_dynamic_param.mean_level_left*0.25));

BSP_LCD_DisplayStringAt(CHAR(0), LINE(10), (uint8_t *)str_pwr, LEFT_MODE);

sprintf((char *)str_pwr, "Right mean power: %ld dB",(int32_t)((float)smr_dynamic_param.mean_level_right*0.25));

BSP_LCD_DisplayStringAt(CHAR(0), LINE(11), (uint8_t *)str_pwr, LEFT_MODE);

}

[KnarfB]

BSP_AUDIO_IN_Init(INPUT_DEVICE_INPUT_LINE_1, 80, AUDIO_FREQUENCY_48K)

doesn't match the implentation in 

32f746gdiscovery-bsp/stm32746g_discovery_audio.c at 64c20f758a907cd873e368502cf16e498934d0ec · STMicroelectronics/32f746gdiscovery-bsp (github.com)

hth

KnarfB

[Andrew Neil]

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@aciuf wrote:

I would like to read the level of audio input signal

---

What "audio input signal"? On what board?

https://community.st.com/t5/community-guidelines/how-to-write-your-question-to-maximize-your-chances-to-find-a/ta-p/575228

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@aciuf wrote:

but I read always 0dB on both channels.

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Have you checked that there is actually any signal present at all?

Is the signal sufficient to read above 0 dB ?

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@aciuf wrote:

This is my code 

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So what testing / investigation / debugging have you done on your code to find what's wrong with it?