modules: Add zephyr lc3 codec

modules/Kconfig

@@ -53,6 +53,9 @@ comment "hal_gigadevice module not available."
 comment "hal_nordic module not available."
 	depends on !ZEPHYR_HAL_NORDIC_MODULE
 
+comment "liblc3codec module not available."
+	depends on !ZEPHYR_LIBLC3CODEC_MODULE
+
 comment "LittleFS module not available."
 	depends on !ZEPHYR_LITTLEFS_MODULE
 

modules/liblc3codec/CMakeLists.txt

@@ -0,0 +1,22 @@
+if(CONFIG_LIBLC3CODEC)
+
+zephyr_library_named(liblc3codec)
+zephyr_library_compile_options(-O3 -ffast-math -Wno-array-bounds)
+
+zephyr_include_directories(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/include)
+zephyr_include_directories(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src)
+
+zephyr_library_sources(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src/attdet.c)
+zephyr_library_sources(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src/bits.c)
+zephyr_library_sources(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src/bwdet.c)
+zephyr_library_sources(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src/energy.c)
+zephyr_library_sources(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src/lc3.c)
+zephyr_library_sources(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src/ltpf.c)
+zephyr_library_sources(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src/mdct.c)
+zephyr_library_sources(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src/plc.c)
+zephyr_library_sources(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src/sns.c)
+zephyr_library_sources(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src/spec.c)
+zephyr_library_sources(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src/tables.c)
+zephyr_library_sources(${ZEPHYR_LIBLC3CODEC_MODULE_DIR}/src/tns.c)
+
+endif()

modules/liblc3codec/Kconfig

@@ -0,0 +1,8 @@
+# Copyright (c) 2022 Bose Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+config LIBLC3CODEC
+	bool "liblc3codec Support"
+	depends on FPU
+	help
+	  This option enables the Android liblc3codec library for Bluetooth LE Audio

samples/bluetooth/unicast_audio_client/boards/native_posix.conf

@@ -0,0 +1,10 @@
+CONFIG_LOG_MODE_IMMEDIATE=y
+CONFIG_BT_TINYCRYPT_ECC=y
+
+CONFIG_LIBLC3CODEC=y
+CONFIG_FPU=y
+
+# For LE-audio at 10ms intervals we need the tick counter to occur more frequently
+# than every 10 ms as each PDU for some reason takes 2 ticks to process.
+CONFIG_SYS_CLOCK_TICKS_PER_SEC=1000
+CONFIG_NATIVE_POSIX_SLOWDOWN_TO_REAL_TIME=y

samples/bluetooth/unicast_audio_client/boards/nrf5340dk_nrf5340_cpuapp.conf

@@ -0,0 +1,11 @@
+CONFIG_BT_CTLR_ADV_EXT=y
+CONFIG_BT_CTLR_ADV_PERIODIC=y
+
+# For LC3 the following configs are needed
+CONFIG_FPU=y
+CONFIG_LIBLC3CODEC=y
+# The LC3 codec uses a large amount of stack. This app runs the codec in the work-queue, hence
+# inctease stack size for that thread.
+CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=4096
+# LC3 lib requires floating point support in the c-lib NEWLIB is one way of getting that.
+CONFIG_NEWLIB_LIBC=y

samples/bluetooth/unicast_audio_client/prj.conf

@@ -3,6 +3,6 @@ CONFIG_BT_DEBUG_LOG=y
 CONFIG_BT_CENTRAL=y
 CONFIG_BT_AUDIO=y
 CONFIG_BT_AUDIO_UNICAST_CLIENT=y
-
+CONFIG_BT_ISO_TX_BUF_COUNT=4
 CONFIG_BT_EXT_ADV=y
 CONFIG_BT_CTLR_ADV_EXT=y

samples/bluetooth/unicast_audio_client/src/main.c

@@ -37,39 +37,137 @@ static K_SEM_DEFINE(sem_stream_qos, 0, 1);
 static K_SEM_DEFINE(sem_stream_enabled, 0, 1);
 static K_SEM_DEFINE(sem_stream_started, 0, 1);
 
-void print_hex(const uint8_t *ptr, size_t len)
+
+#if defined(CONFIG_LIBLC3CODEC)
+
+#include "lc3.h"
+#include "math.h"
+
+/* Current sample do not use codec configuration parameters, hence below shall match the selected
+ * codec configuration.
+ * One sample data buffer en generated and repeated.
+ */
+#define AUDIO_SAMPLE_RATE_HZ    16000
+#define AUDIO_FREQUENCY_HZ      400
+#define AUDIO_LENGTH_US         10000 /* amount of sample data - shall match LC3 frame length */
+#define AUDIO_LENGTH_100US      (AUDIO_LENGTH_US / 100)
+#define NUM_SAMPLES             ((AUDIO_LENGTH_US * AUDIO_SAMPLE_RATE_HZ) / USEC_PER_SEC)
+#define AUDIO_VOLUME            (INT16_MAX - 3000) /* codec does clipping above INT16_MAX - 3000 */
+
+static int16_t audio_buf[NUM_SAMPLES];
+static lc3_encoder_t lc3_encoder;
+static lc3_encoder_mem_48k_t lc3_encoder_mem;
+
+
+/**
+ * Use the math lib to generate a sine-wave using 16 bit samples into a buffer.
+ *
+ * @param buf Destination buffer
+ * @param length_us Length of the buffer in microseconds
+ * @param frequency_hz frequency in Hz
+ * @param sample_rate_hz sample-rate in Hz.
+ */
+static void fill_audio_buf_sin(int16_t *buf, int length_us, int frequency_hz, int sample_rate_hz)
 {
-	while (len-- != 0) {
-		printk("%02x", *ptr++);
+	const int sine_period_samples = sample_rate_hz / frequency_hz;
+	const unsigned int num_samples = (length_us * sample_rate_hz) / USEC_PER_SEC;
+	const float step = 2 * 3.1415 / sine_period_samples;
+
+	for (int i = 0; i < num_samples; i++) {
+		const float sample = sin(i * step);
+
+		buf[i] = (int16_t)(AUDIO_VOLUME * sample);
 	}
 }
 
-static void print_codec(const struct bt_codec *codec)
+static void lc3_audio_timer_timeout(struct k_work *work)
 {
-	printk("codec 0x%02x cid 0x%04x vid 0x%04x count %u\n",
-	       codec->id, codec->cid, codec->vid, codec->data_count);
+	/* For the first call-back we push multiple audio frames to the buffer to use the
+	 * controller ISO buffer to handle jitter.
+	 */
+	const uint8_t prime_count = 2;
+	static int64_t start_time;
+	static int32_t pdu_cnt;
+	int32_t pdu_goal_cnt;
+	int64_t uptime, run_time_ms, run_time_100us;
 
-	for (size_t i = 0; i < codec->data_count; i++) {
-		printk("data #%zu: type 0x%02x len %u\n",
-		       i, codec->data[i].data.type,
-		       codec->data[i].data.data_len);
-		print_hex(codec->data[i].data.data,
-			  codec->data[i].data.data_len -
-				sizeof(codec->data[i].data.type));
-		printk("\n");
+	k_work_schedule(&audio_send_work, K_USEC(preset_16_2_1.qos.interval));
+
+	if (start_time == 0) {
+		/* Read start time and produce the number of frames needed to catch up with any
+		 * inaccuracies in the timer. by calculating the number of frames we should
+		 * have sent and compare to how many were actually sent.
+		 */
+		start_time = k_uptime_get();
 	}
 
-	for (size_t i = 0; i < codec->meta_count; i++) {
-		printk("meta #%zu: type 0x%02x len %u\n",
-		       i, codec->meta[i].data.type,
-		       codec->meta[i].data.data_len);
-		print_hex(codec->meta[i].data.data,
-			  codec->meta[i].data.data_len -
-				sizeof(codec->meta[i].data.type));
-		printk("\n");
+	uptime = k_uptime_get();
+	run_time_ms = uptime - start_time;
+
+	/* PDU count calculations done in 100us units to allow 7.5ms framelength in fixed-point */
+	run_time_100us = run_time_ms * 10;
+	pdu_goal_cnt = run_time_100us / AUDIO_LENGTH_100US;
+
+	/* Add primer value to ensure the controller do not run low on data due to jitter */
+	pdu_goal_cnt += prime_count;
+
+	printk("LC3 encode %d frames\n", pdu_goal_cnt - pdu_cnt);
+
+	while (pdu_cnt < pdu_goal_cnt) {
+
+		int ret;
+		struct net_buf *buf;
+		uint8_t *net_buffer;
+		uint16_t lc3_ret;
+		const uint16_t tx_sdu_len = audio_stream.iso->qos->tx->sdu;
+
+		buf = net_buf_alloc(&tx_pool, K_FOREVER);
+		net_buf_reserve(buf, BT_ISO_CHAN_SEND_RESERVE);
+
+		net_buffer = net_buf_tail(buf);
+		buf->len += tx_sdu_len;
+
+		lc3_ret = lc3_encode(lc3_encoder, LC3_PCM_FORMAT_S16, audio_buf,
+				     1, tx_sdu_len, net_buffer);
+
+		if (lc3_ret == -1) {
+			printk("LC3 encoder failed - wrong parameters?: %d", lc3_ret);
+		}
+
+		ret = bt_audio_stream_send(&audio_stream, buf);
+
+		if (ret < 0) {
+			printk("  Failed to send LC3 audio data (%d)\n", ret);
+			net_buf_unref(buf);
+		} else {
+			printk("  TX LC3 l: %zu\n", tx_sdu_len);
+			pdu_cnt++;
+		}
 	}
 }
 
+static void init_lc3(void)
+{
+	/* Fill audio buffer with Sine wave */
+	fill_audio_buf_sin(audio_buf, AUDIO_LENGTH_US, AUDIO_FREQUENCY_HZ,
+			   AUDIO_SAMPLE_RATE_HZ);
+
+	for (int i = 0; i < NUM_SAMPLES; i++) {
+		printk("%3i: %6i\n", i, audio_buf[i]);
+	}
+
+	/* Create the encoder instance. This shall complete before stream_started() is called. */
+	lc3_encoder = lc3_setup_encoder(AUDIO_LENGTH_US, AUDIO_SAMPLE_RATE_HZ, 0, &lc3_encoder_mem);
+
+	if (lc3_encoder == NULL) {
+		printk("ERROR: Failed to setup LC3 encoder - wrong parameters?\n");
+	}
+}
+
+#else
+
+#define init_lc3(...)
+
 /**
  * @brief Send audio data on timeout
  *
@@ -122,6 +220,41 @@ static void audio_timer_timeout(struct k_work *work)
 	}
 }
 
+#endif
+
+static void print_hex(const uint8_t *ptr, size_t len)
+{
+	while (len-- != 0) {
+		printk("%02x", *ptr++);
+	}
+}
+
+static void print_codec(const struct bt_codec *codec)
+{
+	printk("codec 0x%02x cid 0x%04x vid 0x%04x count %u\n",
+	       codec->id, codec->cid, codec->vid, codec->data_count);
+
+	for (size_t i = 0; i < codec->data_count; i++) {
+		printk("data #%zu: type 0x%02x len %u\n",
+		       i, codec->data[i].data.type,
+		       codec->data[i].data.data_len);
+		print_hex(codec->data[i].data.data,
+			  codec->data[i].data.data_len -
+			  sizeof(codec->data[i].data.type));
+		printk("\n");
+	}
+
+	for (size_t i = 0; i < codec->meta_count; i++) {
+		printk("meta #%zu: type 0x%02x len %u\n",
+		       i, codec->meta[i].data.type,
+		       codec->meta[i].data.data_len);
+		print_hex(codec->meta[i].data.data,
+			  codec->meta[i].data.data_len -
+			  sizeof(codec->meta[i].data.type));
+		printk("\n");
+	}
+}
+
 static bool check_audio_support_and_connect(struct bt_data *data,
 					    void *user_data)
 {
@@ -392,7 +525,11 @@ static int init(void)
 
 	audio_stream.ops = &stream_ops;
 
+#if defined(CONFIG_LIBLC3CODEC)
+	k_work_init_delayable(&audio_send_work, lc3_audio_timer_timeout);
+#else
 	k_work_init_delayable(&audio_send_work, audio_timer_timeout);
+#endif
 
 	return 0;
 }
@@ -492,6 +629,10 @@ static int enable_stream(struct bt_audio_stream *stream)
 {
 	int err;
 
+	if (IS_ENABLED(CONFIG_LIBLC3CODEC)) {
+		init_lc3();
+	}
+
 	err = bt_audio_stream_enable(stream, preset_16_2_1.codec.meta,
 				     preset_16_2_1.codec.meta_count);
 	if (err != 0) {

samples/bluetooth/unicast_audio_server/boards/native_posix.conf

@@ -0,0 +1,10 @@
+CONFIG_LOG_MODE_IMMEDIATE=y
+CONFIG_BT_TINYCRYPT_ECC=y
+
+CONFIG_LIBLC3CODEC=y
+CONFIG_FPU=y
+
+# For LE-audio at 10ms intervals we need the tick counter to occur more frequently
+# than every 10 ms as each PDU for some reason takes 2 ticks to process.
+CONFIG_SYS_CLOCK_TICKS_PER_SEC=1000
+CONFIG_NATIVE_POSIX_SLOWDOWN_TO_REAL_TIME=y

samples/bluetooth/unicast_audio_server/boards/nrf5340dk_nrf5340_cpuapp.conf

@@ -1,2 +1,11 @@
 CONFIG_BT_CTLR_ADV_EXT=y
 CONFIG_BT_CTLR_ADV_PERIODIC=y
+
+# For LC3 the following configs are needed
+CONFIG_FPU=y
+CONFIG_LIBLC3CODEC=y
+# The LC3 codec uses a large amount of stack. This app runs the codec in the work-queue, hence
+# inctease stack size for that thread.
+CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=4096
+# LC3 lib requires floating point support in the c-lib NEWLIB is one way of getting that.
+CONFIG_NEWLIB_LIBC=y