Good Morning,
I need to read a MP3 file from a SD Card, to decode it using firmware and to send it via I2S to an amplifier.
Using some Espressif librairies, I managed to initialise the SDCard and to read an MP3 file on it.
Moreover, I managed to initialise I2S and to send datas manually.
Now I need to find a MP3 decoder to decode the MP3 file.
Do you know if there is some librairies that I can use in order to do it ??
I have seen some examples using ADF (Pipes, Elements, Streams and so on...) that do the job.
Unfortunately, I managed to implement it but the datas at the output of the I2S pins where not correct.
The LR_CLK and the BIT_CLK where not at the good frequency and I did not find how to correct it...
When I configured a 16KHz sample rate, the LR_CLK frequency was 1,35Khz only...
So now, I try to do it manually, and I am looking for a MP3 decoder.
Could you please help me on the subject ?
Best regards,
Thomas TRUILHE
How to decode MP3 on ESP32 ?
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- Posts: 40
- Joined: Wed Jun 22, 2022 12:10 pm
Re: How to decode MP3 on ESP32 ?
Suppose your test file is "/sdcard/test.mp3" you can use follow code directly to play mp3.
Code: Select all
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "nvs_flash.h"
#include "sdkconfig.h"
#include "audio_element.h"
#include "audio_pipeline.h"
#include "audio_event_iface.h"
#include "audio_common.h"
#include "fatfs_stream.h"
#include "i2s_stream.h"
#include "mp3_decoder.h"
#include "wav_encoder.h"
#include "esp_peripherals.h"
#include "periph_sdcard.h"
#include "board.h"
static const char *TAG = "MP3_EXAMPLE";
void app_main(void)
{
audio_pipeline_handle_t pipeline;
audio_element_handle_t fatfs_stream_reader, i2s_stream_writer, mp3_decoder;
esp_log_level_set("*", ESP_LOG_WARN);
esp_log_level_set(TAG, ESP_LOG_INFO);
ESP_LOGI(TAG, "[1.0] Mount sdcard");
// Initialize peripherals management
esp_periph_config_t periph_cfg = DEFAULT_ESP_PERIPH_SET_CONFIG();
esp_periph_set_handle_t set = esp_periph_set_init(&periph_cfg);
// Initialize SD Card peripheral
audio_board_sdcard_init(set, SD_MODE_1_LINE);
ESP_LOGI(TAG, "[2.0] Start codec chip");
audio_board_handle_t board_handle = audio_board_init();
audio_hal_ctrl_codec(board_handle->audio_hal, AUDIO_HAL_CODEC_MODE_BOTH, AUDIO_HAL_CTRL_START);
ESP_LOGI(TAG, "[3.0] Create audio pipeline");
audio_pipeline_cfg_t pipeline_cfg = DEFAULT_AUDIO_PIPELINE_CONFIG();
pipeline = audio_pipeline_init(&pipeline_cfg);
mem_assert(pipeline);
fatfs_stream_cfg_t fatfs_cfg = FATFS_STREAM_CFG_DEFAULT();
fatfs_cfg.type = AUDIO_STREAM_READER;
fatfs_stream_reader = fatfs_stream_init(&fatfs_cfg);
i2s_stream_cfg_t i2s_cfg = I2S_STREAM_CFG_DEFAULT();
i2s_cfg.type = AUDIO_STREAM_WRITER;
i2s_stream_writer = i2s_stream_init(&i2s_cfg);
mp3_decoder_cfg_t mp3_dec_cfg = DEFAULT_MP3_DECODER_CONFIG();
mp3_decoder = mp3_decoder_init(&mp3_dec_cfg);
ESP_LOGI(TAG, "[3.1] Register all elements to audio pipeline");
audio_pipeline_register(pipeline, fatfs_stream_reader, "file_read");
audio_pipeline_register(pipeline, mp3_decoder, "mp3_decoder");
audio_pipeline_register(pipeline, i2s_stream_writer, "i2s");
ESP_LOGI(TAG, "[3.2] Link it together [sdcard]-->fatfs_stream-->mp3_decoder-->i2s_stream");
audio_pipeline_link(pipeline, (const char *[]) {
"file_read", "mp3_decoder", "i2s"
}, 3);
ESP_LOGI(TAG, "[3.3] Set up uri (file as fatfs_stream, wav as wav decoder, and default output is i2s)");
audio_element_set_uri(fatfs_stream_reader, "/sdcard/test.mp3"); // change your test file name here
ESP_LOGI(TAG, "[4.0] Set up event listener");
audio_event_iface_cfg_t evt_cfg = AUDIO_EVENT_IFACE_DEFAULT_CFG();
audio_event_iface_handle_t evt = audio_event_iface_init(&evt_cfg);
ESP_LOGI(TAG, "[4.1] Listening event from all elements of pipeline");
audio_pipeline_set_listener(pipeline, evt);
ESP_LOGI(TAG, "[4.2] Listening event from peripherals");
audio_event_iface_set_listener(esp_periph_set_get_event_iface(set), evt);
ESP_LOGI(TAG, "[5.0] Start audio_pipeline");
audio_pipeline_run(pipeline);
ESP_LOGI(TAG, "[6.0] Listen for all pipeline events");
while (1) {
audio_event_iface_msg_t msg;
esp_err_t ret = audio_event_iface_listen(evt, &msg, portMAX_DELAY);
if (ret != ESP_OK) {
ESP_LOGE(TAG, "[ * ] Event interface error : %d", ret);
continue;
}
if (msg.source_type == AUDIO_ELEMENT_TYPE_ELEMENT && msg.source == (void *)mp3_decoder
&& msg.cmd == AEL_MSG_CMD_REPORT_MUSIC_INFO) {
audio_element_info_t music_info = {0};
audio_element_getinfo(mp3_decoder, &music_info);
ESP_LOGI(TAG, "[ * ] Receive music info from wav decoder, sample_rates=%d, bits=%d, ch=%d",
music_info.sample_rates, music_info.bits, music_info.channels);
i2s_stream_set_clk(i2s_stream_writer, music_info.sample_rates, music_info.bits, music_info.channels);
continue;
}
if (msg.source_type == AUDIO_ELEMENT_TYPE_ELEMENT && msg.cmd == AEL_MSG_CMD_REPORT_STATUS
&& (((int)msg.data == AEL_STATUS_STATE_STOPPED) || ((int)msg.data == AEL_STATUS_STATE_FINISHED))) {
ESP_LOGW(TAG, "[ * ] Stop event received");
break;
}
}
ESP_LOGI(TAG, "[7.0] Stop audio_pipeline and release all resources");
audio_pipeline_stop(pipeline);
audio_pipeline_wait_for_stop(pipeline);
audio_pipeline_terminate(pipeline);
audio_pipeline_unregister(pipeline, fatfs_stream_reader);
audio_pipeline_unregister(pipeline, mp3_decoder);
audio_pipeline_unregister(pipeline, i2s_stream_writer);
/* Terminate the pipeline before removing the listener */
audio_pipeline_remove_listener(pipeline);
/* Stop all peripheral before removing the listener */
esp_periph_set_stop_all(set);
audio_event_iface_remove_listener(esp_periph_set_get_event_iface(set), evt);
/* Make sure audio_pipeline_remove_listener & audio_event_iface_remove_listener are called before destroying event_iface */
audio_event_iface_destroy(evt);
/* Release all resources */
audio_pipeline_deinit(pipeline);
audio_element_deinit(fatfs_stream_reader);
audio_element_deinit(mp3_decoder);
audio_element_deinit(i2s_stream_writer);
esp_periph_set_destroy(set);
}
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- Posts: 7
- Joined: Sun Aug 13, 2023 10:35 pm
Re: How to decode MP3 on ESP32 ?
Did you ever figure this out? I've been trying to do the exact same thing!
Re: How to decode MP3 on ESP32 ?
Try the esp-adf player example called pipeline_play_sdcard_music. It works perfectly for me on mp3 files on an SD card using the ESP32-LryaT-Mini v1.2.
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