Audio Application Framework

[中文]

When using the VoIP feature of ESP-ADF, how to eliminate echo during calls between a mobile phone and an ESP32 device?

  • Espressif provides an Acoustic Echo Cancelation (AEC) algorithm based on ESP32 and ESP32-S3 chips. For details, please refer to the algorithm examples.

  • Note that the effect of AEC not only depends on software parameter configuration and debugging, but also on hardware design, such as distortion-free playback, noise-free recording, and problem-free echo reference signal, etc. For this part, it is recommended to refer to the Espressif’s design on the ESP32-Lyrat-Mini development board and ESP32-S3-Korvo-2 development board.

Does the use of the ESP32-Korvo-DU1906 development board require the use of Baidu Cloud?

  • The ESP32-Korvo-DU1906 development board example is only for testing with Baidu Cloud, and a Profile is required.

  • Please contact Baidu Cloud to check the relevant business access terms, see Preparation for using voice services.

Does the official VoIP example provided by Espressif support RTP?

  • In ESP-ADF, the default VoIP provided is based on SIP, and the protocol utilizes RTP.

  • You can use the VoIP example under Espressif SDK ESP-ADF.

Is the SIP protocol in ESP-ADF open-source?

The protocol is currently not open-source and is provided for external calls in the form of a library.

Can ESP-ADF examples implement the volume adjustment function of Bluetooth headsets?

Such as: pipeline_a2dp_sink_and_hfp, pipeline_a2dp_sink_stream, pipeline_bt_sink

  • Currently, ESP-ADF does not support AVRCP’s tuning operation. ESP-IDF release/v4.0 and later releases have already supported this function. You can try to use the a2dp_sink example and a2dp_source example in ESP-IDF.

  • The function will be directly supported in the ADF examples in the future.

I want to use a sensor on the I2C of ESP32-LyraT. Is there an example on how to read I2C device data?

Please refer to the i2c example.

How to output 32-bit I2S audio data?

Please refer to the following code:

i2s_stream_cfg_t i2s_writer_cfg = I2S_STREAM_CFG_DEFAULT();
i2s_writer_cfg.type = AUDIO_STREAM_WRITER;
i2s_writer_cfg.stack_in_ext = true;
i2s_writer_cfg.task_core = 1;
i2s_writer_cfg.need_expand = true;
i2s_writer_cfg.expand_src_bits = 16;
i2s_writer = i2s_stream_init(&i2s_writer_cfg);

Why do I always get an error when compiling example/get-started/play-mp3 with ESP-ADF and ESP-IDF v4.1?

Error log: fatal error: audio_type_def.h: No such file or directory

  • The file audio_type_def.h is located in the esp-adf-libs of ESP-ADF. If this file cannot be found during the compilation process, it indicates that ESP-ADF v2.4 may not have been correctly detected, especially the submodules may not have been updated.

  • To correctly detect ESP-ADF v2.4, please follow the steps described in Update to a stable release version.

  • Try executing the following commands and recompile.

    cd $ADF_PATH
git fetch
git checkout v2.4
git submodule update --init --recursive

Where can I check the ESP-IDF version supported by ESP-ADF?

Will integrating DuerOS occupy the recording function of the ESP32-LyraT development board throughout the process?

The current design occupies the recording data throughout the process. However, you can enable the multi_output function of I2S_stream to output the recording data to the desired location through this channel.

Does ESP-ADF support the development of custom voice recognition keywords?

The voice training interface has not yet been opened. You can directly use the free wake-up word “Hi, Espressif”. If you have customization requirements, please email sales@espressif.com for details.

Does ESP-ADF support running Alexa examples on the ESP32-LyraTD-MSC v2.1 development board?

ESP-ADF does not directly support Alexa examples. For Alexa examples, please refer to esp-va-sdk.

Regarding voice recognition on ESP32, can you recommend a suitable development board for localization?

We recommend using the ESP32-Lyrat-Mini development board or the ESP32-S3-Korvo-2 development board for localization.

Does ESP32 have a development board that supports both MIC and AUX pickup?

The ESP32-lyraT-4.3 development board supports both MIC and AUX pickup.

How to implement call function using the ESP32-LyraT development board?

You can refer to the VoIP example VoIP.

What is the maximum power of supported speakers for ESP32 series audio development board?

  • ESP32 development board uses NS4150 PA by default, and its maximum power is 3 W.

  • You may change the PA design according to needs.

Does Espressif’s voice wake-up solution have specific requirements regarding environmental noise?

The current Espressif voice solution can meet the environmental requirements of a signal-to-noise ratio of less than 5 dB. For some fixed noise scenarios, it can even be less than 0 dB (need to be optimized for the actual product).

If there is an AUX input on the ESP32’s AI development board, can the MIC still be used to pick up sound?

  • The ESP-ADF development framework can choose various ways to pick up sound, including MIC input and Line-in.

  • The pickup method selection is as follows:

    typedef enum {
  AUDIO_HAL_CODEC_MODE_ENCODE = 1, /*! <select adc */      // MIC pickup
  AUDIO_HAL_CODEC_MODE_DECODE, /*! <select dac*/
  AUDIO_HAL_CODEC_MODE_BOTH, /*! <select both adc and dac */   //  MIC + speaker
  AUDIO_HAL_CODEC_MODE_LINE_IN, /*! <set adc channel */,             // microphone pickup
} Audio_hal_codec_mode_t;

  • The pickup method configuration is as follows:

    audio_board_handle_t board_handle = audio_board_init();
audio_hal_ctrl_codec(board_handle->audio_hal, AUDIO_HAL_CODEC_MODE_DECODE, AUDIO_HAL_CTRL_START);   // If you want to pick up sound from the MIC, modify this configuration option.

When designing an audio development board with the ESP32-WROVER-B module and ES8311, which pins can be selected for the MCLK clock?

Can the ESP32-WROVER-E module use a single I2S to realize simultaneous playback and recording?

Yes. You can refer to the ESP32-LyraT getting started guide.

Do Espressif modules support Spotify Connect?

:CHIP: ESP32 | ESP32-S2 | ESP32-S3 :

Not supported yet. It is recommended to consider using dlna, which can achieve a similar effect.

When running the korvo_du1906 example on an ESP32-Korvo-DU1906 board, a reboot caused the following error message: Guru Meditation Error: Core 0 panic’ed (IllegalInstruction). Exception was unhandled. How to resolve such issue?

  • Please check the power supply.

  • Provide power to the entire system. It is recommended to use at least a 5 V/2 A power adapter to ensure stable power supply.

Can ESP-DSP fft run 4096, 8192, and more samples?

Yes, it supports up to 32 K samples. The maximum value can be configured in menuconfig. For example, in the fft demo, the configuration steps are idf.py menuconfig > Component config > DSP Library > Maximum FFT length > (*)32768.

How to connect a microphone to ESP32?

  • You can connect I2S peripheral if it is a digital microphone.

  • You can connect ADC peripheral if it is an analog microphone.

Does ESP32 support analog audio or digital audio output?

  • ESP32 supports DAC analog audio output, which can be used to play simple audio such as prompt tones.

  • ESP32 supports PWM analog audio output, which is slightly better than DAC. Demonstration code: esp-iot-solution.

  • ESP32 also supports I2S digital audio output. For I2S configurable pins, please refer to ESP32 Datasheet > Chapter Peripherals and Sensors.

What audio formats does the ESP32 chip support?

ESP32 supports audio formats such as MP3, AAC, FLAC, WAV, OGG, OPUS, AMR, G.711, etc. For more information, please refer to the instructions under ESP-ADF SDK.

How to use the ESP32 chip to decode compressed audio?

For applications using the ESP32 chip to decode compressed audio, refer to the examples in the esp-adf/examples/recorder folder.

Where is the code example for ESP-LED-Strip?

The corresponding code examples are stored in ESP-ADF. Please refer to the led_pixels example.

Does ESP32 support online voice recognition?

Yes, it does. Please refer to the esp-adf/examples/dueros example.

Does ESP32 support volume adjustment of Bluetooth headphones?

Yes. ESP32 uses the Bluetooth AVRCP tuning protocol. You can test the function with the esp-adf/examples/player/pipeline_bt_sink example.


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