Merge branch 'bt/opt_audio_datapath_v4.3' into 'release/v4.3'

bt/optimized a2dp_sink audio datapath (v4.3)

See merge request espressif/esp-idf!21224

components/bt/host/bluedroid/btc/profile/std/a2dp/btc_a2dp_sink.c

@@ -85,7 +85,6 @@ enum {
 
 /* 18 frames is equivalent to 6.89*18*2.9 ~= 360 ms @ 44.1 khz, 20 ms mediatick */
 #define MAX_OUTPUT_A2DP_SNK_FRAME_QUEUE_SZ     (25)
-#define JITTER_BUFFER_WATER_LEVEL (5)
 
 #define BTC_A2DP_SNK_DATA_QUEUE_IDX            (1)
 
@@ -696,9 +695,7 @@ UINT8 btc_a2dp_sink_enque_buf(BT_HDR *p_pkt)
         p_msg->num_frames_to_be_processed = (*((UINT8 *)(p_msg + 1) + p_msg->offset)) & 0x0f;
         APPL_TRACE_VERBOSE("btc_a2dp_sink_enque_buf %d + \n", p_msg->num_frames_to_be_processed);
         fixed_queue_enqueue(a2dp_sink_local_param.btc_aa_snk_cb.RxSbcQ, p_msg, FIXED_QUEUE_MAX_TIMEOUT);
-        if (fixed_queue_length(a2dp_sink_local_param.btc_aa_snk_cb.RxSbcQ) >= JITTER_BUFFER_WATER_LEVEL) {
-            osi_thread_post_event(a2dp_sink_local_param.btc_aa_snk_cb.data_ready_event, OSI_THREAD_MAX_TIMEOUT);
-        }
+        osi_thread_post_event(a2dp_sink_local_param.btc_aa_snk_cb.data_ready_event, OSI_THREAD_MAX_TIMEOUT);
     } else {
         /* let caller deal with a failed allocation */
         APPL_TRACE_WARNING("btc_a2dp_sink_enque_buf No Buffer left - ");

examples/bluetooth/bluedroid/classic_bt/a2dp_sink/main/bt_app_core.c

@@ -13,12 +13,23 @@
 #include "freertos/FreeRTOSConfig.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/queue.h"
+#include "freertos/semphr.h"
 #include "freertos/task.h"
 #include "esp_log.h"
 #include "bt_app_core.h"
 #include "driver/i2s.h"
 #include "freertos/ringbuf.h"
 
+
+#define RINGBUF_HIGHEST_WATER_LEVEL    (32 * 1024)
+#define RINGBUF_PREFETCH_WATER_LEVEL   (20 * 1024)
+
+enum {
+    RINGBUFFER_MODE_PROCESSING,    /* ringbuffer is buffering incoming audio data, I2S is working */
+    RINGBUFFER_MODE_PREFETCHING,   /* ringbuffer is buffering incoming audio data, I2S is waiting */
+    RINGBUFFER_MODE_DROPPING       /* ringbuffer is not buffering (dropping) incoming audio data, I2S is working */
+};
+
 /*******************************
  * STATIC FUNCTION DECLARATIONS
  ******************************/
@@ -40,6 +51,8 @@ static xQueueHandle s_bt_app_task_queue = NULL;  /* handle of work queue */
 static xTaskHandle s_bt_app_task_handle = NULL;  /* handle of application task  */
 static xTaskHandle s_bt_i2s_task_handle = NULL;  /* handle of I2S task */
 static RingbufHandle_t s_ringbuf_i2s = NULL;     /* handle of ringbuffer for I2S */
+static SemaphoreHandle_t s_i2s_write_semaphore = NULL;
+static uint16_t ringbuffer_mode = RINGBUFFER_MODE_PROCESSING;
 
 /*******************************
  * STATIC FUNCTION DEFINITIONS
@@ -94,14 +107,28 @@ static void bt_i2s_task_handler(void *arg)
 {
     uint8_t *data = NULL;
     size_t item_size = 0;
+    /**
+     * The total length of DMA buffer of I2S is:
+     * `dma_frame_num * dma_desc_num * i2s_channel_num * i2s_data_bit_width / 8`.
+     * Transmit `dma_frame_num * dma_desc_num` bytes to DMA is trade-off.
+     */
+    const size_t item_size_upto = 60 * 6;
     size_t bytes_written = 0;
 
     for (;;) {
-        /* receive data from ringbuffer and write it to I2S DMA transmit buffer */
-        data = (uint8_t *)xRingbufferReceive(s_ringbuf_i2s, &item_size, (portTickType)portMAX_DELAY);
-        if (item_size != 0){
-            i2s_write(0, data, item_size, &bytes_written, portMAX_DELAY);
-            vRingbufferReturnItem(s_ringbuf_i2s, (void *)data);
+        if (pdTRUE == xSemaphoreTake(s_i2s_write_semaphore, portMAX_DELAY)) {
+            for (;;) {
+                item_size = 0;
+                /* receive data from ringbuffer and write it to I2S DMA transmit buffer */
+                data = (uint8_t *)xRingbufferReceiveUpTo(s_ringbuf_i2s, &item_size, (TickType_t)pdMS_TO_TICKS(5), item_size_upto);
+                if (item_size == 0) {
+                    ESP_LOGI(BT_APP_CORE_TAG, "ringbuffer underflowed! mode changed: RINGBUFFER_MODE_PREFETCHING");
+                    ringbuffer_mode = RINGBUFFER_MODE_PREFETCHING;
+                    break;
+                }
+                i2s_write(0, data, item_size, &bytes_written, portMAX_DELAY);
+                vRingbufferReturnItem(s_ringbuf_i2s, (void *)data);
+            }
         }
     }
 }
@@ -157,10 +184,17 @@ void bt_app_task_shut_down(void)
 
 void bt_i2s_task_start_up(void)
 {
-    if ((s_ringbuf_i2s = xRingbufferCreate(8 * 1024, RINGBUF_TYPE_BYTEBUF)) == NULL) {
+    ESP_LOGI(BT_APP_CORE_TAG, "ringbuffer data empty! mode changed: RINGBUFFER_MODE_PREFETCHING");
+    ringbuffer_mode = RINGBUFFER_MODE_PREFETCHING;
+    if ((s_i2s_write_semaphore = xSemaphoreCreateBinary()) == NULL) {
+        ESP_LOGE(BT_APP_CORE_TAG, "%s, Semaphore create failed", __func__);
         return;
     }
-    xTaskCreate(bt_i2s_task_handler, "BtI2STask", 1024, NULL, configMAX_PRIORITIES - 3, &s_bt_i2s_task_handle);
+    if ((s_ringbuf_i2s = xRingbufferCreate(RINGBUF_HIGHEST_WATER_LEVEL, RINGBUF_TYPE_BYTEBUF)) == NULL) {
+        ESP_LOGE(BT_APP_CORE_TAG, "%s, ringbuffer create failed", __func__);
+        return;
+    }
+    xTaskCreate(bt_i2s_task_handler, "BtI2STask", 2048, NULL, configMAX_PRIORITIES - 3, &s_bt_i2s_task_handle);
 }
 
 void bt_i2s_task_shut_down(void)
@@ -173,11 +207,44 @@ void bt_i2s_task_shut_down(void)
         vRingbufferDelete(s_ringbuf_i2s);
         s_ringbuf_i2s = NULL;
     }
+    if (s_i2s_write_semaphore) {
+        vSemaphoreDelete(s_i2s_write_semaphore);
+        s_i2s_write_semaphore = NULL;
+    }
 }
 
 size_t write_ringbuf(const uint8_t *data, size_t size)
 {
-    BaseType_t done = xRingbufferSend(s_ringbuf_i2s, (void *)data, size, (portTickType)portMAX_DELAY);
+    size_t item_size = 0;
+    BaseType_t done = pdFALSE;
+
+    if (ringbuffer_mode == RINGBUFFER_MODE_DROPPING) {
+        ESP_LOGW(BT_APP_CORE_TAG, "ringbuffer is full, drop this packet!");
+        vRingbufferGetInfo(s_ringbuf_i2s, NULL, NULL, NULL, NULL, &item_size);
+        if (item_size <= RINGBUF_PREFETCH_WATER_LEVEL) {
+            ESP_LOGI(BT_APP_CORE_TAG, "ringbuffer data decreased! mode changed: RINGBUFFER_MODE_PROCESSING");
+            ringbuffer_mode = RINGBUFFER_MODE_PROCESSING;
+        }
+        return 0;
+    }
+
+    done = xRingbufferSend(s_ringbuf_i2s, (void *)data, size, (TickType_t)0);
+
+    if (!done) {
+        ESP_LOGW(BT_APP_CORE_TAG, "ringbuffer overflowed, ready to decrease data! mode changed: RINGBUFFER_MODE_DROPPING");
+        ringbuffer_mode = RINGBUFFER_MODE_DROPPING;
+    }
+
+    if (ringbuffer_mode == RINGBUFFER_MODE_PREFETCHING) {
+        vRingbufferGetInfo(s_ringbuf_i2s, NULL, NULL, NULL, NULL, &item_size);
+        if (item_size >= RINGBUF_PREFETCH_WATER_LEVEL) {
+            ESP_LOGI(BT_APP_CORE_TAG, "ringbuffer data increased! mode changed: RINGBUFFER_MODE_PROCESSING");
+            ringbuffer_mode = RINGBUFFER_MODE_PROCESSING;
+            if (pdFALSE == xSemaphoreGive(s_i2s_write_semaphore)) {
+                ESP_LOGE(BT_APP_CORE_TAG, "semphore give failed");
+            }
+        }
+    }
 
     return done ? size : 0;
 }