Create a platform layer

Create platform implementations for linux and esp32s3.
Get linux audio working using pulseaudio.

Author: adamac

src/CMakeLists.txt

@@ -1,12 +1,14 @@
-set(COMMON_SRC "webrtc.cpp" "main.cpp" "http.cpp")
+set(COMMON_SRC "webrtc.cpp" "main.cpp" "http.cpp" "media.cpp")
 
 if(IDF_TARGET STREQUAL linux)
 	idf_component_register(
-		SRCS ${COMMON_SRC}
+		SRCS ${COMMON_SRC} "platform_linux.cpp"
 		REQUIRES peer esp-libopus esp_http_client)
+	target_link_libraries(${COMPONENT_LIB} PRIVATE pulse pulse-simple)
+	target_link_libraries(${COMPONENT_LIB} PRIVATE "-lbsd")
 else()
 	idf_component_register(
-		SRCS ${COMMON_SRC} "wifi.cpp" "media.cpp"
+		SRCS ${COMMON_SRC} "platform_esp32s3.cpp" "wifi.cpp"
 		REQUIRES driver esp_wifi nvs_flash peer esp_psram esp-libopus esp_http_client)
 endif()
 

src/http.cpp

@@ -3,6 +3,7 @@
 #include <string.h>
 
 #include "main.h"
+#include "platform.h"
 
 #ifndef MIN
 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
@@ -34,9 +35,7 @@ esp_err_t oai_http_event_handler(esp_http_client_event_t *evt) {
       ESP_LOGD(LOG_TAG, "HTTP_EVENT_ON_DATA, len=%d", evt->data_len);
       if (esp_http_client_is_chunked_response(evt->client)) {
         ESP_LOGE(LOG_TAG, "Chunked HTTP response not supported");
-#ifndef LINUX_BUILD
-        esp_restart();
-#endif
+        oai_platform_restart();
       }
 
       if (output_len == 0 && evt->user_data) {
@@ -88,9 +87,7 @@ void oai_http_request(char *offer, char *answer) {
   esp_err_t err = esp_http_client_perform(client);
   if (err != ESP_OK || esp_http_client_get_status_code(client) != 201) {
     ESP_LOGE(LOG_TAG, "Error perform http request %s", esp_err_to_name(err));
-#ifndef LINUX_BUILD
-    esp_restart();
-#endif
+    oai_platform_restart();
   }
 
   esp_http_client_cleanup(client);

src/main.cpp

@@ -4,29 +4,19 @@
 #include <esp_log.h>
 #include <peer.h>
 
-#ifndef LINUX_BUILD
-#include "nvs_flash.h"
+#include "platform.h"
 
-extern "C" void app_main(void) {
-  esp_err_t ret = nvs_flash_init();
-  if (ret == ESP_ERR_NVS_NO_FREE_PAGES ||
-      ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
-    ESP_ERROR_CHECK(nvs_flash_erase());
-    ret = nvs_flash_init();
-  }
-  ESP_ERROR_CHECK(ret);
+#ifndef LINUX_BUILD
+#define MAIN extern "C" void app_main(void)
+#else
+#define MAIN int main(void)
+#endif
 
+MAIN {
   ESP_ERROR_CHECK(esp_event_loop_create_default());
   peer_init();
-  oai_init_audio_capture();
+  oai_platform_init_audio_capture();
   oai_init_audio_decoder();
   oai_wifi();
   oai_webrtc();
 }
-#else
-int main(void) {
-  ESP_ERROR_CHECK(esp_event_loop_create_default());
-  peer_init();
-  oai_webrtc();
-}
-#endif

src/main.h

@@ -1,3 +1,6 @@
+#ifndef _MAIN_H_
+#define _MAIN_H_
+
 #include <peer.h>
 
 #define LOG_TAG "realtimeapi-sdk"
@@ -11,3 +14,5 @@ void oai_send_audio(PeerConnection *peer_connection);
 void oai_audio_decode(uint8_t *data, size_t size);
 void oai_webrtc();
 void oai_http_request(char *offer, char *answer);
+
+#endif

src/media.cpp

@@ -1,144 +1,68 @@
-#include <driver/i2s.h>
 #include <opus.h>
+#include <stdio.h>
 
 #include "main.h"
+#include "platform.h"
 
 #define OPUS_OUT_BUFFER_SIZE 1276  // 1276 bytes is recommended by opus_encode
-#define SAMPLE_RATE 8000
-#define BUFFER_SAMPLES 320
-
-#define MCLK_PIN 0
-#define DAC_BCLK_PIN 15
-#define DAC_LRCLK_PIN 16
-#define DAC_DATA_PIN 17
-#define ADC_BCLK_PIN 38
-#define ADC_LRCLK_PIN 39
-#define ADC_DATA_PIN 40
 
 #define OPUS_ENCODER_BITRATE 30000
 #define OPUS_ENCODER_COMPLEXITY 0
 
-void oai_init_audio_capture() {
-  i2s_config_t i2s_config_out = {
-      .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_TX),
-      .sample_rate = SAMPLE_RATE,
-      .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
-      .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
-      .communication_format = I2S_COMM_FORMAT_I2S_MSB,
-      .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
-      .dma_buf_count = 8,
-      .dma_buf_len = BUFFER_SAMPLES,
-      .use_apll = 1,
-      .tx_desc_auto_clear = true,
-  };
-  if (i2s_driver_install(I2S_NUM_0, &i2s_config_out, 0, NULL) != ESP_OK) {
-    printf("Failed to configure I2S driver for audio output");
-    return;
-  }
-
-  i2s_pin_config_t pin_config_out = {
-      .mck_io_num = MCLK_PIN,
-      .bck_io_num = DAC_BCLK_PIN,
-      .ws_io_num = DAC_LRCLK_PIN,
-      .data_out_num = DAC_DATA_PIN,
-      .data_in_num = I2S_PIN_NO_CHANGE,
-  };
-  if (i2s_set_pin(I2S_NUM_0, &pin_config_out) != ESP_OK) {
-    printf("Failed to set I2S pins for audio output");
-    return;
-  }
-  i2s_zero_dma_buffer(I2S_NUM_0);
+const auto kCaptureFrameSize = kCaptureSampleRate * 20 / 1000;
+const auto kPlaybackFrameSize = kPlaybackSampleRate * 20 / 1000;
 
-  i2s_config_t i2s_config_in = {
-      .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX),
-      .sample_rate = SAMPLE_RATE,
-      .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
-      .channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,
-      .communication_format = I2S_COMM_FORMAT_I2S_MSB,
-      .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
-      .dma_buf_count = 8,
-      .dma_buf_len = BUFFER_SAMPLES,
-      .use_apll = 1,
-  };
-  if (i2s_driver_install(I2S_NUM_1, &i2s_config_in, 0, NULL) != ESP_OK) {
-    printf("Failed to configure I2S driver for audio input");
-    return;
-  }
-
-  i2s_pin_config_t pin_config_in = {
-      .mck_io_num = MCLK_PIN,
-      .bck_io_num = ADC_BCLK_PIN,
-      .ws_io_num = ADC_LRCLK_PIN,
-      .data_out_num = I2S_PIN_NO_CHANGE,
-      .data_in_num = ADC_DATA_PIN,
-  };
-  if (i2s_set_pin(I2S_NUM_1, &pin_config_in) != ESP_OK) {
-    printf("Failed to set I2S pins for audio input");
-    return;
-  }
-}
-
-static opus_int16 *output_buffer = NULL;
-static size_t output_buffer_size = BUFFER_SAMPLES * sizeof(opus_int16);
 static OpusDecoder *opus_decoder = NULL;
+static OpusEncoder *opus_encoder = NULL;
+
+static opus_int16 output_buffer[kPlaybackFrameSize * kPlaybackChannelCount];
+static opus_int16 input_buffer[kCaptureFrameSize * kCaptureChannelCount];
+static uint8_t encoder_output_buffer[OPUS_OUT_BUFFER_SIZE];
 
 void oai_init_audio_decoder() {
   int decoder_error = 0;
-  opus_decoder = opus_decoder_create(SAMPLE_RATE, 2, &decoder_error);
+  opus_decoder = opus_decoder_create(kPlaybackSampleRate, kPlaybackChannelCount,
+                                     &decoder_error);
   if (decoder_error != OPUS_OK) {
     printf("Failed to create OPUS decoder");
     return;
   }
-
-  output_buffer = (opus_int16 *)malloc(output_buffer_size);
 }
 
 void oai_audio_decode(uint8_t *data, size_t size) {
-  int decoded_size =
-      opus_decode(opus_decoder, data, size, output_buffer, BUFFER_SAMPLES, 0);
+  int decoded_size = opus_decode(opus_decoder, data, size, output_buffer,
+                                 sizeof(output_buffer), 0);
 
   if (decoded_size > 0) {
     size_t bytes_written = 0;
-    i2s_write(I2S_NUM_0, output_buffer, output_buffer_size,
-              &bytes_written, portMAX_DELAY);
+    oai_platform_audio_write((char *)output_buffer, sizeof(output_buffer),
+                             &bytes_written);
   }
 }
 
-static OpusEncoder *opus_encoder = NULL;
-static opus_int16 *encoder_input_buffer = NULL;
-static uint8_t *encoder_output_buffer = NULL;
-
 void oai_init_audio_encoder() {
   int encoder_error;
-  opus_encoder = opus_encoder_create(SAMPLE_RATE, 1, OPUS_APPLICATION_VOIP,
-                                     &encoder_error);
+  opus_encoder = opus_encoder_create(kCaptureSampleRate, kCaptureChannelCount,
+                                     OPUS_APPLICATION_VOIP, &encoder_error);
   if (encoder_error != OPUS_OK) {
     printf("Failed to create OPUS encoder");
     return;
   }
 
-  if (opus_encoder_init(opus_encoder, SAMPLE_RATE, 1, OPUS_APPLICATION_VOIP) !=
-      OPUS_OK) {
-    printf("Failed to initialize OPUS encoder");
-    return;
-  }
-
   opus_encoder_ctl(opus_encoder, OPUS_SET_BITRATE(OPUS_ENCODER_BITRATE));
   opus_encoder_ctl(opus_encoder, OPUS_SET_COMPLEXITY(OPUS_ENCODER_COMPLEXITY));
   opus_encoder_ctl(opus_encoder, OPUS_SET_SIGNAL(OPUS_SIGNAL_VOICE));
-  encoder_input_buffer = (opus_int16 *)malloc(BUFFER_SAMPLES);
-  encoder_output_buffer = (uint8_t *)malloc(OPUS_OUT_BUFFER_SIZE);
 }
 
 void oai_send_audio(PeerConnection *peer_connection) {
   size_t bytes_read = 0;
 
-  i2s_read(I2S_NUM_1, encoder_input_buffer, BUFFER_SAMPLES, &bytes_read,
-           portMAX_DELAY);
+  oai_platform_audio_read((char *)input_buffer, sizeof(input_buffer),
+                          &bytes_read);
 
   auto encoded_size =
-      opus_encode(opus_encoder, encoder_input_buffer, BUFFER_SAMPLES / 2,
-                  encoder_output_buffer, OPUS_OUT_BUFFER_SIZE);
+      opus_encode(opus_encoder, input_buffer, kCaptureFrameSize,
+                  encoder_output_buffer, sizeof(encoder_output_buffer));
 
   peer_connection_send_audio(peer_connection, encoder_output_buffer,
                              encoded_size);

src/media.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include "peer_connection.h"
+
+void oai_send_audio(PeerConnection *peer_connection);

src/platform.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdlib.h>
+
+#include "peer_connection.h"
+
+inline constexpr int kCaptureSampleRate = 8000;
+inline constexpr int kCaptureChannelCount = 1;
+inline constexpr int kPlaybackSampleRate = 8000;
+inline constexpr int kPlaybackChannelCount = 2;
+
+void oai_platform_init(void);
+void oai_platform_restart(void);
+void oai_platform_init_audio_capture(void);
+void oai_platform_audio_write(char *output_buffer, size_t output_buffer_size,
+                              size_t *bytes_written);
+void oai_platform_audio_read(char *input_buffer, size_t input_buffer_size,
+                             size_t *bytes_read);
+void oai_platform_send_audio_task(PeerConnection *peer_connection);