diff --git a/src/le-audio/broadcast_audio_uri_builder.c b/src/le-audio/broadcast_audio_uri_builder.c
index 3ade53996..978e47413 100644
--- a/src/le-audio/broadcast_audio_uri_builder.c
+++ b/src/le-audio/broadcast_audio_uri_builder.c
@@ -41,7 +41,6 @@
 #include "btstack_base64_encoder.h"
 #include "btstack_util.h"
 
-#include <stdio.h>
 #include <stdint.h>
 #include <string.h>
 #include <inttypes.h>
@@ -59,10 +58,30 @@ static inline bool broadcast_audio_uri_builder_have_space(const broadcast_audio_
     return builder->len + len <= builder->size;
 }
 
-void broadcast_audio_uri_builder_init(broadcast_audio_uri_builder_t * builder, uint8_t * buffer, uint16_t size){
+static inline char * broadcast_audio_uri_builder_get_ptr( const broadcast_audio_uri_builder_t * builder ) {
+   return &builder->buffer[builder->len];
+}
+
+bool broadcast_audio_uri_builder_init(broadcast_audio_uri_builder_t * builder, char * buffer, uint16_t size){
     builder->buffer = buffer;
     builder->size = size;
     builder->len = 0;
+    return broadcast_audio_uri_builder_append_string(builder, "BLUETOOTH:UUID:184F;");
+}
+
+bool broadcast_audio_uri_builder_finalize(broadcast_audio_uri_builder_t * builder){
+    bool ok = broadcast_audio_uri_builder_append_string(builder, ";");
+    uint16_t remaining;
+    void *ptr;
+    if(ok) {
+        remaining = broadcast_audio_uri_builder_get_remaining_space(builder);
+        ptr = broadcast_audio_uri_builder_get_ptr(builder);
+        ok = (remaining > 0);
+    }
+    if(ok) {
+        memset(ptr, 0, remaining);
+    }
+    return ok;
 }
 
 uint16_t broadcast_audio_uri_builder_get_remaining_space(const broadcast_audio_uri_builder_t * builder){
@@ -93,20 +112,17 @@ bool broadcast_audio_uri_builder_append_broadcast_name(broadcast_audio_uri_build
     if( !ok ) {
         return ok;
     }
-    uint8_t *ptr =&builder->buffer[builder->len];
+    char *ptr = broadcast_audio_uri_builder_get_ptr(builder);
     size_t remaining = broadcast_audio_uri_builder_get_remaining_space( builder );
-    ptr = btstack_base64_encoder(broadcast_name, strlen(broadcast_name), ptr, &remaining);
-    if( ptr == NULL ) {
-        goto error_return;
+    ok = btstack_base64_encoder_process_block(broadcast_name, strlen(broadcast_name), ptr, &remaining);
+    if( ok ) {
+        builder->len += remaining;
+        ok = broadcast_audio_uri_builder_append_string( builder, ";" );
     }
-    ok = broadcast_audio_uri_builder_append_string( builder, ";" );
     if( !ok ) {
-        goto error_return;
+        builder->len = len;
     }
-    return true;
-error_return:
-    builder->len = len;
-    return false;
+    return ok;
 }
 
 bool broadcast_audio_uri_builder_append_advertiser_address_type(broadcast_audio_uri_builder_t * builder, bd_addr_type_t advertiser_address_type){
@@ -116,14 +132,9 @@ bool broadcast_audio_uri_builder_append_advertiser_address_type(broadcast_audio_
 }
 
 bool broadcast_audio_uri_builder_append_standard_quality(broadcast_audio_uri_builder_t * builder, bool standard_quality){
-    uint8_t *ptr = &builder->buffer[builder->len];
-    uint16_t remaining = broadcast_audio_uri_builder_get_remaining_space( builder );
-    int len = snprintf((char*)ptr, remaining, "SQ:%u;", (int) standard_quality);
-    if((len>0) && (len<remaining)) {
-        builder->len += len-1;
-        return true;
-    }
-    return false;
+    char buffer[10];
+    btstack_snprintf_assert_complete(buffer, sizeof(buffer), "SQ:%u;", (int) standard_quality);
+    return broadcast_audio_uri_builder_append_string(builder, buffer);
 }
 
 bool broadcast_audio_uri_builder_append_high_quality(broadcast_audio_uri_builder_t * builder, bool high_quality){
@@ -133,47 +144,73 @@ bool broadcast_audio_uri_builder_append_high_quality(broadcast_audio_uri_builder
 }
 
 bool broadcast_audio_uri_builder_append_advertiser_address(broadcast_audio_uri_builder_t * builder, bd_addr_t advertiser_address){
+    char buffer[13];
     uint16_t len = builder->len;
     bool ok = broadcast_audio_uri_builder_append_string(builder,"AD:");
-    if (ok){
-        char buffer[13];
-        broadcast_audio_uri_builder_string_hexdump((uint8_t *)buffer, (const uint8_t *) advertiser_address, 6);
-        buffer[12] = ';';
-        broadcast_audio_uri_builder_append_bytes(builder, (const uint8_t *) buffer, sizeof(buffer));
-    } else {
+    broadcast_audio_uri_builder_string_hexdump((uint8_t *)buffer, (const uint8_t *) advertiser_address, 6);
+    buffer[12] = ';';
+    if(ok){
+        ok = broadcast_audio_uri_builder_append_bytes(builder, (const uint8_t *) buffer, sizeof(buffer));
+    }
+    if(!ok){
         builder->len = len;
     }
     return ok;
 }
 
 bool broadcast_audio_uri_builder_append_broadcast_id(broadcast_audio_uri_builder_t * builder, uint32_t broadcast_id){
+    uint8_t buffer[7];
     uint16_t len = builder->len;
     bool ok = broadcast_audio_uri_builder_append_string(builder,"BI:");
-    if (ok){
-        uint8_t buffer[7];
-        uint8_t big_endian_id[3];
-        big_endian_store_24(big_endian_id, 0, broadcast_id);
-        broadcast_audio_uri_builder_string_hexdump(buffer, big_endian_id, 3);
-        buffer[6] = ';';
-        broadcast_audio_uri_builder_append_bytes(builder, (const uint8_t *) buffer, sizeof(buffer));
-    } else {
+
+    uint8_t big_endian_id[3];
+    big_endian_store_24(big_endian_id, 0, broadcast_id);
+    broadcast_audio_uri_builder_string_hexdump(buffer, big_endian_id, 3);
+    buffer[6] = ';';
+
+    if(ok){
+        ok = broadcast_audio_uri_builder_append_bytes(builder, (const uint8_t *) buffer, sizeof(buffer));
+    }
+    if(!ok) {
         builder->len = len;
     }
     return ok;
-
 }
 
-bool broadcast_audio_uri_builder_append_broadcast_code(broadcast_audio_uri_builder_t * builder, const uint8_t * broadcast_code){
-    UNUSED(broadcast_code);
+bool broadcast_audio_uri_builder_append_broadcast_code_as_bytes(broadcast_audio_uri_builder_t * builder, const uint8_t * broadcast_code){
     uint16_t len = builder->len;
     bool ok = broadcast_audio_uri_builder_append_string(builder,"BC:");
-    if (ok){
-        uint8_t buffer[25];
-        // TODO: base64
-        memcpy(buffer, "MDEyMzQ1Njc4OWFiY2RlZg==", 24);
-        buffer[24] = ';';
-        broadcast_audio_uri_builder_append_bytes(builder, (const uint8_t *) buffer, sizeof(buffer));
-    } else {
+    if (!ok){
+        return ok;
+    }
+    char *ptr = broadcast_audio_uri_builder_get_ptr(builder);
+    size_t remaining = broadcast_audio_uri_builder_get_remaining_space(builder);
+    ok = btstack_base64_encoder_process_block(broadcast_code, 16, ptr, &remaining);
+    if(ok) {
+        builder->len += remaining;
+        ok = broadcast_audio_uri_builder_append_string( builder, ";" );
+    }
+    if(!ok){
+        builder->len = len;
+    }
+    return ok;
+}
+
+bool broadcast_audio_uri_builder_append_broadcast_code_as_string(broadcast_audio_uri_builder_t * builder, const char *broadcast_code){
+    uint16_t len = builder->len;
+    bool ok = broadcast_audio_uri_builder_append_string(builder,"BC:");
+    if (!ok){
+        return ok;
+    }
+    char *ptr = broadcast_audio_uri_builder_get_ptr(builder);
+    size_t remaining = broadcast_audio_uri_builder_get_remaining_space(builder);
+    size_t block_size = btstack_min(strlen(broadcast_code), 16);
+    ok = btstack_base64_encoder_process_block(broadcast_code, block_size, ptr, &remaining);
+    if(ok) {
+        builder->len += remaining;
+        ok = broadcast_audio_uri_builder_append_string( builder, ";" );
+    }
+    if(!ok){
         builder->len = len;
     }
     return ok;
@@ -184,16 +221,41 @@ bool broadcast_audio_uri_builder_append_vendor_specific(broadcast_audio_uri_buil
     UNUSED(data_len);
     uint16_t len = builder->len;
     bool ok = broadcast_audio_uri_builder_append_string(builder, "VS:");
-    if (ok){
+    size_t remaining, olen;
+    btstack_base64_state_t state;
+    if(ok) {
+        char buffer[9] = "ID:0000;";
         uint8_t vendor_id_big_endian_id[2];
         big_endian_store_16(vendor_id_big_endian_id, 0, vendor_id);
-        uint8_t vendor_id_hex[4];
-        memset(vendor_id_hex, 0, sizeof(vendor_id_hex));
-        broadcast_audio_uri_builder_string_hexdump(vendor_id_hex, vendor_id_hex, 2);
-        // TODO: base64(vendor_id_hex + data)
+        broadcast_audio_uri_builder_string_hexdump((uint8_t*)&buffer[3], vendor_id_big_endian_id, 2);
+        char *ptr = broadcast_audio_uri_builder_get_ptr(builder);
+        remaining = broadcast_audio_uri_builder_get_remaining_space(builder);
+        olen = remaining;
+        btstack_base64_encoder_stream_init( &state );
+        ssize_t ret = btstack_base64_encoder_stream( &state, buffer, strlen(buffer), ptr, &olen );
+        ok = ((ret>0) && !(olen>remaining));
+    }
+    if(ok) {
+        builder->len += olen;
+        remaining -= olen;
+        olen = remaining;
+        char *ptr = broadcast_audio_uri_builder_get_ptr(builder);
+        ssize_t ret = btstack_base64_encoder_stream( &state, data, data_len, ptr, &olen );
+        ok = ((ret>0) && !(olen>remaining));
+    }
+    if(ok) {
+        builder->len += olen;
+        remaining -= olen;
+        olen = remaining;
+        char *ptr = broadcast_audio_uri_builder_get_ptr(builder);
+        ssize_t ret = btstack_base64_encoder_stream_final(&state, ptr, &olen);
+        ok = ((ret>=0) && (olen<remaining));
+    }
+    if (ok){
+        builder->len += olen;
         ok = broadcast_audio_uri_builder_append_string(builder, ";");
     }
-    if (ok == false){
+    if (!ok){
         builder->len = len;
     }
     return ok;
@@ -201,59 +263,115 @@ bool broadcast_audio_uri_builder_append_vendor_specific(broadcast_audio_uri_buil
 
 bool broadcast_audio_uri_builder_append_advertising_sid(broadcast_audio_uri_builder_t * builder, uint8_t advertising_sid){
     char buffer[10];
-    btstack_snprintf_assert_complete(buffer, sizeof(buffer), "AS:%02X;", advertising_sid);
+    btstack_snprintf_assert_complete(buffer, sizeof(buffer), "AS:%X;", advertising_sid);
     return broadcast_audio_uri_builder_append_string(builder, buffer);
 }
 
 bool broadcast_audio_uri_builder_append_pa_interval(broadcast_audio_uri_builder_t * builder, uint16_t pa_interval){
     char buffer[10];
-    btstack_snprintf_assert_complete(buffer, sizeof(buffer), "PI:%04" PRIX16 ";", pa_interval);
+    btstack_snprintf_assert_complete(buffer, sizeof(buffer), "PI:%" PRIX16 ";", pa_interval);
     return broadcast_audio_uri_builder_append_string(builder, buffer);
 }
 
 bool broadcast_audio_uri_builder_append_num_subgroups(broadcast_audio_uri_builder_t * builder, uint8_t num_subgroups){
     char buffer[10];
-    btstack_snprintf_assert_complete(buffer, sizeof(buffer), "NS:%02X", num_subgroups);
+    btstack_snprintf_assert_complete(buffer, sizeof(buffer), "NS:%X;", num_subgroups);
     return broadcast_audio_uri_builder_append_string(builder, buffer);
 }
 
 bool broadcast_audio_uri_builder_append_bis_sync(broadcast_audio_uri_builder_t * builder, uint32_t bis_sync){
     char buffer[10];
-    btstack_snprintf_assert_complete(buffer, sizeof(buffer), "BS:%04" PRIX32 ";", bis_sync);
+    btstack_snprintf_assert_complete(buffer, sizeof(buffer), "BS:%" PRIX32 ";", bis_sync);
     return broadcast_audio_uri_builder_append_string(builder, buffer);
 }
 
 bool broadcast_audio_uri_builder_append_sg_number_of_bises(broadcast_audio_uri_builder_t * builder, uint32_t sg_number_of_bises){
     char buffer[10];
-    btstack_snprintf_assert_complete(buffer, sizeof(buffer), "NB:%04" PRIX32 ";", sg_number_of_bises);
+    btstack_snprintf_assert_complete(buffer, sizeof(buffer), "NB:%" PRIX32 ";", sg_number_of_bises);
     return broadcast_audio_uri_builder_append_string(builder, buffer);
 }
 
-bool broadcast_audio_uri_builder_append_sg_metadata(broadcast_audio_uri_builder_t * builder, const uint8_t * metadata, uint16_t metadata_len){
+bool broadcast_audio_uri_builder_sg_metadata_begin(broadcast_audio_uri_builder_t * builder){
     uint16_t len = builder->len;
     bool ok = broadcast_audio_uri_builder_append_string(builder, "SM:");
-    if (ok && (metadata_len > 0)) {
-        // TODO: base64(data)
-        ok = broadcast_audio_uri_builder_append_bytes(builder, metadata, metadata_len);
+    if (ok) {
+        btstack_base64_encoder_stream_init(&builder->state);
+    }
+    if(!ok){
+        builder->len = len;
+    }
+    return ok;
+}
+
+bool broadcast_audio_uri_builder_sg_metadata_append_ltv(broadcast_audio_uri_builder_t * builder, uint8_t metadata_len, const uint8_t type, const uint8_t * metadata){
+    if(metadata_len == 0) {
+        return true;
+    }
+    uint16_t len = builder->len;
+    char *ptr = broadcast_audio_uri_builder_get_ptr(builder);
+    size_t remaining = broadcast_audio_uri_builder_get_remaining_space(builder);
+    size_t olen = remaining;
+    uint8_t l = metadata_len + 1; // account for type octet
+    ssize_t ret = btstack_base64_encoder_stream(&builder->state, &l, 1, ptr, &olen);
+    bool ok = (ret>0) && !(olen>remaining);
+    if (ok) {
+        builder->len += olen;
+        ptr = broadcast_audio_uri_builder_get_ptr(builder);
+        remaining = broadcast_audio_uri_builder_get_remaining_space(builder);
+        olen = remaining;
+        ret = btstack_base64_encoder_stream(&builder->state, &type, 1, ptr, &olen);
+        ok = (ret>0) && !(olen>remaining);
     }
     if (ok) {
-        ok = broadcast_audio_uri_builder_append_string(builder, ";");
+        builder->len += olen;
+        ptr = broadcast_audio_uri_builder_get_ptr(builder);
+        remaining = broadcast_audio_uri_builder_get_remaining_space(builder);
+        olen = remaining;
+        ret = btstack_base64_encoder_stream(&builder->state, metadata, metadata_len, ptr, &olen);
+        ok = (ret>0) && !(olen>remaining);
+    }
+    if(ok) {
+        builder->len += olen;
     } else {
         builder->len = len;
     }
     return ok;
 }
 
+bool broadcast_audio_uri_builder_sg_metadata_end(broadcast_audio_uri_builder_t * builder){
+    uint16_t len = builder->len;
+
+    char *ptr = broadcast_audio_uri_builder_get_ptr(builder);
+    size_t remaining = broadcast_audio_uri_builder_get_remaining_space(builder);
+    size_t olen = remaining;
+    ssize_t ret = btstack_base64_encoder_stream_final(&builder->state, ptr, &olen);
+    bool ok = (ret>=0) && !(olen>remaining);
+
+    if (ok) {
+        builder->len += olen;
+        ok = broadcast_audio_uri_builder_append_string(builder, ";");
+    }
+    if(!ok){
+        builder->len = len;
+    }
+    return ok;
+}
+
 bool broadcast_audio_uri_builder_append_public_broadcast_announcement_metadata(broadcast_audio_uri_builder_t * builder, const uint8_t * metadata, uint16_t metadata_len){
+    if(metadata_len == 0) {
+        return true;
+    }
     uint16_t len = builder->len;
     bool ok = broadcast_audio_uri_builder_append_string(builder, "PM:");
-    if (ok && metadata_len > 0) {
-        // TODO: base64(data)
-        ok = broadcast_audio_uri_builder_append_bytes(builder, metadata, metadata_len);
+    if (ok) {
+        char *ptr = broadcast_audio_uri_builder_get_ptr(builder);
+        size_t remaining = broadcast_audio_uri_builder_get_remaining_space(builder);
+        ok = btstack_base64_encoder_process_block(metadata, metadata_len, ptr, &remaining);
     }
     if (ok) {
         ok = broadcast_audio_uri_builder_append_string(builder, ";");
-    } else {
+    }
+    if(!ok){
         builder->len = len;
     }
     return ok;
diff --git a/src/le-audio/broadcast_audio_uri_builder.h b/src/le-audio/broadcast_audio_uri_builder.h
index 41dfcae9d..febfe137e 100644
--- a/src/le-audio/broadcast_audio_uri_builder.h
+++ b/src/le-audio/broadcast_audio_uri_builder.h
@@ -45,15 +45,17 @@
 #include <stdint.h>
 #include "btstack_bool.h"
 #include "bluetooth.h"
+#include "btstack_base64_encoder.h"
 
 #if defined __cplusplus
 extern "C" {
 #endif
 
 typedef struct {
-    uint8_t * buffer;
+    char * buffer;
     uint16_t  size;
     uint16_t len;
+    btstack_base64_state_t state;
 } broadcast_audio_uri_builder_t;
 
 /**
@@ -61,8 +63,18 @@ typedef struct {
  * @param builder
  * @param buffer to setup BASE
  * @param size of buffer
+ * @return true if there was sufficient space in the underlying buffer
  */
-void broadcast_audio_uri_builder_init(broadcast_audio_uri_builder_t * builder, uint8_t * buffer, uint16_t size);
+bool broadcast_audio_uri_builder_init(broadcast_audio_uri_builder_t * builder, char * buffer, uint16_t size);
+
+/**
+ * Finalize Broadcast Audio URI
+ * @param builder
+ * @param buffer to setup BASE
+ * @param size of buffer
+ * @return true if there was sufficient space in the underlying buffer
+ */
+bool broadcast_audio_uri_builder_finalize(broadcast_audio_uri_builder_t * builder);
 
 /**
  * @brief Query remaining space in buffer
@@ -128,12 +140,24 @@ bool broadcast_audio_uri_builder_append_advertiser_address(broadcast_audio_uri_b
 bool broadcast_audio_uri_builder_append_broadcast_id(broadcast_audio_uri_builder_t * builder, uint32_t broadcast_id);
 
 /**
- * Append Broadcast ID
+ * Append Broadcast Code
  * @param builder
- * @param Broadcast Code (128 bit)
+ * @param Broadcast Code (128 bit) as byte array
  * @return
  */
-bool broadcast_audio_uri_builder_append_broadcast_code(broadcast_audio_uri_builder_t * builder, const uint8_t * broadcast_code);
+bool broadcast_audio_uri_builder_append_broadcast_code_as_bytes(broadcast_audio_uri_builder_t * builder, const uint8_t * broadcast_code);
+
+/**
+ * Append Broadcast Code
+ * @param builder
+ * @param Broadcast Code (128 bit) as string
+ * @return
+ *
+ * The broadcast code will include the first 16 bytes of the given string.
+ * If the string is smaller only the bytes till the null termination are included.
+ * Bigger strings are truncated after 16 bytes.
+ */
+bool broadcast_audio_uri_builder_append_broadcast_code_as_string(broadcast_audio_uri_builder_t * builder, const char * broadcast_code);
 
 /**
  * Append Standard Quality
@@ -202,13 +226,28 @@ bool broadcast_audio_uri_builder_append_bis_sync(broadcast_audio_uri_builder_t *
 bool broadcast_audio_uri_builder_append_sg_number_of_bises(broadcast_audio_uri_builder_t * builder, uint32_t sg_number_of_bises);
 
 /**
- * Append SG_Metadata
+ * Start a SG_Metadata block
  * @param builder
- * @param metadata
- * @param metadata_len
  * @return
  */
-bool broadcast_audio_uri_builder_append_sg_metadata(broadcast_audio_uri_builder_t * builder, const uint8_t * metadata, uint16_t metadata_len);
+bool broadcast_audio_uri_builder_sg_metadata_begin(broadcast_audio_uri_builder_t * builder);
+
+/**
+ * Append ltv to SG_Metadata block
+ * @param builder
+ * @param metadata_len
+ * @param type
+ * @param metadata
+ * @return
+ */
+bool broadcast_audio_uri_builder_sg_metadata_append_ltv(broadcast_audio_uri_builder_t * builder, uint8_t metadata_len, uint8_t type, const uint8_t * metadata);
+
+/**
+ * Finalize SG_Metadata block
+ * @param builder
+ * @return
+ */
+bool broadcast_audio_uri_builder_sg_metadata_end(broadcast_audio_uri_builder_t * builder);
 
 /**
  * Append Public Broadcast Announcement Metadata