Apply audio filter using esp_audio.h

[teddykishi]

Hi

Here my setup:
esp-idf: V4.4.4
esp-adf: V2.4
Hardware: ESP32-Lyrat Mini

i'm using the library esp_audio.h (esp_audio/include/esp_audio.h) and it work fine.

But I would like to apply audio filters from esp_sonic.h (esp_codec/include/processing/esp_sonic.h) to my audio such as the pitch or write my own audio processing code to change compression or echo.

How to get the audio data from esp_audio.h in order to alter them then to play it live ?

here is my code ```// initializing esp_audio as an audio player -- START
static void setup_player(void) {
if (player ) {
return ;
}
esp_audio_cfg_t cfg = DEFAULT_ESP_AUDIO_CONFIG();
//audio_board_handle_t board_handle = audio_board_init();
board_handle = audio_board_init();
cfg.vol_handle = board_handle->audio_hal;
cfg.vol_set = (audio_volume_set)audio_hal_set_volume;
cfg.vol_get = (audio_volume_get)audio_hal_get_volume;
cfg.prefer_type = ESP_AUDIO_PREFER_MEM; // ESP_AUDIO_PREFER_SPEED
cfg.resample_rate = 48000;
cfg.evt_que = xQueueCreate(3, sizeof(esp_audio_state_t));
player = esp_audio_create(&cfg);
audio_hal_ctrl_codec(board_handle->audio_hal, AUDIO_HAL_CODEC_MODE_BOTH, AUDIO_HAL_CTRL_START);
xTaskCreate(esp_audio_state_task, "player_task", 4096, cfg.evt_que, 1, NULL);

// Create readers and add to esp_audio
fatfs_stream_cfg_t fs_reader = FATFS_STREAM_CFG_DEFAULT();
fs_reader.type = AUDIO_STREAM_READER;
i2s_stream_cfg_t i2s_reader = I2S_STREAM_CFG_DEFAULT();
i2s_reader.type = AUDIO_STREAM_READER;
raw_stream_cfg_t raw_reader = RAW_STREAM_CFG_DEFAULT();
raw_reader.type = AUDIO_STREAM_READER;


audio_element_handle_t i2s_read_h = i2s_stream_init(&i2s_reader);
i2s_stream_set_clk(i2s_read_h, 48000, 16, 2);
esp_audio_input_stream_add(player, raw_stream_init(&raw_reader));
esp_audio_input_stream_add(player, fatfs_stream_init(&fs_reader));
esp_audio_input_stream_add(player, i2s_read_h);
http_stream_cfg_t http_cfg = HTTP_STREAM_CFG_DEFAULT();
http_cfg.event_handle = _http_stream_event_handle;
http_cfg.type = AUDIO_STREAM_READER;
http_cfg.enable_playlist_parser = true;
audio_element_handle_t http_stream_reader = http_stream_init(&http_cfg);
esp_audio_input_stream_add(player, http_stream_reader);

amr_decoder_cfg_t  amr_dec_cfg  = DEFAULT_AMR_DECODER_CONFIG();
flac_decoder_cfg_t flac_dec_cfg = DEFAULT_FLAC_DECODER_CONFIG();
ogg_decoder_cfg_t  ogg_dec_cfg  = DEFAULT_OGG_DECODER_CONFIG();
opus_decoder_cfg_t opus_dec_cfg = DEFAULT_OPUS_DECODER_CONFIG();
mp3_decoder_cfg_t  mp3_dec_cfg  = DEFAULT_MP3_DECODER_CONFIG();
wav_decoder_cfg_t  wav_dec_cfg  = DEFAULT_WAV_DECODER_CONFIG();
aac_decoder_cfg_t  aac_dec_cfg  = DEFAULT_AAC_DECODER_CONFIG();

esp_audio_codec_lib_add(player, AUDIO_CODEC_TYPE_DECODER, amr_decoder_init(&amr_dec_cfg));
esp_audio_codec_lib_add(player, AUDIO_CODEC_TYPE_DECODER, flac_decoder_init(&flac_dec_cfg));
esp_audio_codec_lib_add(player, AUDIO_CODEC_TYPE_DECODER, ogg_decoder_init(&ogg_dec_cfg));
esp_audio_codec_lib_add(player, AUDIO_CODEC_TYPE_DECODER, decoder_opus_init(&opus_dec_cfg));
esp_audio_codec_lib_add(player, AUDIO_CODEC_TYPE_DECODER, wav_decoder_init(&wav_dec_cfg));
esp_audio_codec_lib_add(player, AUDIO_CODEC_TYPE_DECODER, aac_decoder_init(&aac_dec_cfg));

mp3_el = mp3_decoder_init(&mp3_dec_cfg);
esp_audio_codec_lib_add(player, AUDIO_CODEC_TYPE_DECODER, mp3_el);
audio_element_handle_t m4a_dec_cfg = aac_decoder_init(&aac_dec_cfg);
audio_element_set_tag(m4a_dec_cfg, "m4a");
esp_audio_codec_lib_add(player, AUDIO_CODEC_TYPE_DECODER, m4a_dec_cfg);

audio_element_handle_t ts_dec_cfg = aac_decoder_init(&aac_dec_cfg);
audio_element_set_tag(ts_dec_cfg, "ts");
esp_audio_codec_lib_add(player, AUDIO_CODEC_TYPE_DECODER, ts_dec_cfg);

wav_encoder_cfg_t wav_enc_cfg = DEFAULT_WAV_ENCODER_CONFIG();
esp_audio_codec_lib_add(player, AUDIO_CODEC_TYPE_ENCODER, wav_encoder_init(&wav_enc_cfg));
// END WAIT TO PLAY

// Create writers and add to esp_audio
fatfs_stream_cfg_t fs_writer = FATFS_STREAM_CFG_DEFAULT();
fs_writer.type = AUDIO_STREAM_WRITER;

i2s_stream_cfg_t i2s_writer = I2S_STREAM_CFG_DEFAULT();
i2s_writer.type = AUDIO_STREAM_WRITER;

raw_stream_cfg_t raw_writer = RAW_STREAM_CFG_DEFAULT();
raw_writer.type = AUDIO_STREAM_WRITER;
audio_element_handle_t i2s_h = i2s_stream_init(&i2s_writer);
int channels = 2; // mono 2 for stereo
i2s_stream_set_clk(i2s_h, 48000, 16, channels);

equalizer_cfg_t equalizer_cfg = DEFAULT_EQUALIZER_CONFIG();
int set_value_gain[10] = {-12, -6, 0, 6, 12, 12, 6, 0, -6, -12};
equalizer_cfg.samplerate = 48000;
equalizer_cfg.channel = 2;
equalizer_cfg.set_gain = set_value_gain; 
audio_element_handle_t equalizer = equalizer_init(&equalizer_cfg);

esp_audio_output_stream_add(player, i2s_h);
esp_audio_output_stream_add(player, equalizer);
esp_audio_output_stream_add(player, fatfs_stream_init(&fs_writer));
esp_audio_output_stream_add(player, raw_stream_init(&raw_writer));


// Set default volume
esp_audio_vol_set(player, 50);

AUDIO_MEM_SHOW(TAG);
ESP_LOGI(TAG, "esp_audio instance is:%p\r\n", player);

}

void on_button_press(uint8_t num, char* song_url) {

esp_audio_media_type_set(player, MEDIA_SRC_TYPE_MUSIC_SD);

esp_err_t ret = esp_audio_play(player, AUDIO_CODEC_TYPE_DECODER, song_url, 0);

esp_audio_music_info_t music_info = {0};
esp_audio_music_info_get(player, &music_info);

ESP_LOGI(TAG, "[ * ] Receive music info from wav decoder, sample_rates=%d, bits=%d, ch=%d, bps=%d",
            music_info.sample_rates, music_info.bits, music_info.channels, music_info.bps);

if (ret == ESP_OK) {
    // [TO DO] add pitch filter 
    // [TO DO] add echo filter 
} else {
    ESP_LOGE(TAG, "Failed to play URL: %s", song_url);
}

}

If I'm not clear enough please ask me questions.
Thank you very much