xref: /btstack/src/classic/a2dp_source.c (revision e883851f1d92ba6f82ca45f4db83673c9bf54f19)

/*
 * Copyright (C) 2016 BlueKitchen GmbH
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 * 4. Any redistribution, use, or modification is done solely for
 *    personal benefit and not for any commercial purpose or for
 *    monetary gain.
 *
 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * Please inquire about commercial licensing options at
 * [email protected]
 *
 */

/**
 * Supported use cases:
 * - single incoming connection: sep discovery starts and stream will get setup if remote sink sep with SBC is found
 * - single outgoing connection: see above
 * - outgoing and incoming connection to same device:
 *    - if outgoing is triggered first, incoming will get ignored.
 *    - if incoming starts first, start ougoing will fail, but incoming will succeed.
 * - outgoing and incoming connections to different devices:
 *    - if outgoing is first, incoming gets ignored.
 *    - if incoming starts first SEP discovery will get stopped and outgoing will succeed.
 */

#define BTSTACK_FILE__ "a2dp_source.c"

#include <stdint.h>
#include <string.h>

#include "bluetooth_psm.h"
#include "bluetooth_sdp.h"
#include "btstack_debug.h"
#include "btstack_event.h"
#include "classic/a2dp_source.h"
#include "classic/avdtp_source.h"
#include "classic/avdtp_util.h"
#include "classic/sdp_util.h"
#include "l2cap.h"

#define AVDTP_MAX_SEP_NUM 10
#define A2DP_SET_CONFIG_DELAY_MS 150

static const char * default_a2dp_source_service_name = "BTstack A2DP Source Service";
static const char * default_a2dp_source_service_provider_name = "BTstack A2DP Source Service Provider";
static bool sep_found_w2_set_configuration = false;
static btstack_timer_source_t a2dp_source_set_config_timer;

//
static bool     outgoing_active;

// discover remote seps
static a2dp_state_t a2dp_source_state = A2DP_IDLE;
static uint16_t     a2dp_source_cid;
static uint16_t     num_remote_seps = 0;
static avdtp_sep_t  remote_seps[AVDTP_MAX_SEP_NUM];

static bool stream_endpoint_configured = false;

static avdtp_stream_endpoint_context_t sc;
static btstack_packet_handler_t a2dp_source_packet_handler_user;

static void a2dp_source_packet_handler_internal(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
static void a2dp_discover_seps_with_next_waiting_connection(void);

static void a2dp_source_streaming_emit_connection_failed(avdtp_connection_t * connection, uint8_t local_seid, uint8_t status) {
    uint8_t event[14];
    int pos = 0;
    event[pos++] = HCI_EVENT_A2DP_META;
    event[pos++] = sizeof(event) - 2;
    event[pos++] = A2DP_SUBEVENT_STREAM_ESTABLISHED;
    little_endian_store_16(event, pos, connection->avdtp_cid);
    pos += 2;
    reverse_bd_addr(connection->remote_addr, &event[pos]);
    pos += 6;
    event[pos++] = local_seid;
    event[pos++] = 0;
    event[pos++] = status;

    (*a2dp_source_packet_handler_user)(HCI_EVENT_PACKET, 0, event, sizeof(event));
}

void a2dp_source_create_sdp_record(uint8_t * service, uint32_t service_record_handle, uint16_t supported_features, const char * service_name, const char * service_provider_name){
    uint8_t* attribute;
    de_create_sequence(service);

    // 0x0000 "Service Record Handle"
    de_add_number(service, DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_RECORD_HANDLE);
    de_add_number(service, DE_UINT, DE_SIZE_32, service_record_handle);

    // 0x0001 "Service Class ID List"
    de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST);
    attribute = de_push_sequence(service);
    {
        de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AUDIO_SOURCE);
    }
    de_pop_sequence(service, attribute);

    // 0x0004 "Protocol Descriptor List"
    de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST);
    attribute = de_push_sequence(service);
    {
        uint8_t* l2cpProtocol = de_push_sequence(attribute);
        {
            de_add_number(l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
            de_add_number(l2cpProtocol,  DE_UINT, DE_SIZE_16, BLUETOOTH_PSM_AVDTP);
        }
        de_pop_sequence(attribute, l2cpProtocol);

        uint8_t* avProtocol = de_push_sequence(attribute);
        {
            de_add_number(avProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVDTP);  // avProtocol_service
            de_add_number(avProtocol,  DE_UINT, DE_SIZE_16,  0x0103);  // version
        }
        de_pop_sequence(attribute, avProtocol);
    }
    de_pop_sequence(service, attribute);

    // 0x0005 "Public Browse Group"
    de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BROWSE_GROUP_LIST); // public browse group
    attribute = de_push_sequence(service);
    {
        de_add_number(attribute,  DE_UUID, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PUBLIC_BROWSE_ROOT);
    }
    de_pop_sequence(service, attribute);

    // 0x0009 "Bluetooth Profile Descriptor List"
    de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BLUETOOTH_PROFILE_DESCRIPTOR_LIST);
    attribute = de_push_sequence(service);
    {
        uint8_t *a2dProfile = de_push_sequence(attribute);
        {
            de_add_number(a2dProfile,  DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_ADVANCED_AUDIO_DISTRIBUTION);
            de_add_number(a2dProfile,  DE_UINT, DE_SIZE_16, 0x0103);
        }
        de_pop_sequence(attribute, a2dProfile);
    }
    de_pop_sequence(service, attribute);


    // 0x0100 "Service Name"
    de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0100);
    if (service_name){
        de_add_data(service,  DE_STRING, strlen(service_name), (uint8_t *) service_name);
    } else {
        de_add_data(service,  DE_STRING, strlen(default_a2dp_source_service_name), (uint8_t *) default_a2dp_source_service_name);
    }

    // 0x0100 "Provider Name"
    de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0102);
    if (service_provider_name){
        de_add_data(service,  DE_STRING, strlen(service_provider_name), (uint8_t *) service_provider_name);
    } else {
        de_add_data(service,  DE_STRING, strlen(default_a2dp_source_service_provider_name), (uint8_t *) default_a2dp_source_service_provider_name);
    }

    // 0x0311 "Supported Features"
    de_add_number(service, DE_UINT, DE_SIZE_16, 0x0311);
    de_add_number(service, DE_UINT, DE_SIZE_16, supported_features);
}

static void a2dp_signaling_emit_reconfigured(uint16_t cid, uint8_t local_seid, uint8_t status){
    uint8_t event[7];
    int pos = 0;
    event[pos++] = HCI_EVENT_A2DP_META;
    event[pos++] = sizeof(event) - 2;
    event[pos++] = A2DP_SUBEVENT_STREAM_RECONFIGURED;
    little_endian_store_16(event, pos, cid);
    pos += 2;
    event[pos++] = local_seid;
    event[pos++] = status;
    (*a2dp_source_packet_handler_user)(HCI_EVENT_PACKET, 0, event, sizeof(event));
}

static void a2dp_source_discover_stream_endpoints(uint16_t avdtp_cid){
    a2dp_source_cid = avdtp_cid;
    avdtp_source_discover_stream_endpoints(avdtp_cid);
}

static void a2dp_source_set_config_timer_handler(btstack_timer_source_t * timer){
    if (stream_endpoint_configured) return;

    uint16_t avdtp_cid = (uint16_t)(uintptr_t) btstack_run_loop_get_timer_context(timer);
	avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
	btstack_run_loop_set_timer_context(&a2dp_source_set_config_timer, NULL);

    if (connection == NULL) {
        log_info("a2dp_discover_seps_with_next_waiting_connection");
        a2dp_discover_seps_with_next_waiting_connection();
        return;
    }

    a2dp_source_discover_stream_endpoints(avdtp_cid);
}

static void a2dp_source_set_config_timer_start(uint16_t avdtp_cid){
    log_info("a2dp_source_set_config_timer_start cid 0%02x", avdtp_cid);
    btstack_run_loop_remove_timer(&a2dp_source_set_config_timer);
    btstack_run_loop_set_timer_handler(&a2dp_source_set_config_timer,a2dp_source_set_config_timer_handler);
    btstack_run_loop_set_timer(&a2dp_source_set_config_timer, A2DP_SET_CONFIG_DELAY_MS);
    btstack_run_loop_set_timer_context(&a2dp_source_set_config_timer, (void *)(uintptr_t)avdtp_cid);
    btstack_run_loop_add_timer(&a2dp_source_set_config_timer);
}

static void a2dp_source_set_config_timer_stop(void){
    log_info("a2dp_source_set_config_timer_stop");
    btstack_run_loop_remove_timer(&a2dp_source_set_config_timer);
	btstack_run_loop_set_timer_context(&a2dp_source_set_config_timer, NULL);
}

static void a2dp_start_discovering_seps(avdtp_connection_t * connection){
    a2dp_source_state = A2DP_DISCOVER_SEPS;
    sc.active_remote_sep_index = 0;
    num_remote_seps = 0;
    memset(remote_seps, 0, sizeof(avdtp_sep_t) * AVDTP_MAX_SEP_NUM);
    connection->a2dp_source_discover_seps = false;

    // if we initiated the connection, start config right away, else wait a bit to give remote a chance to do it first
    if (outgoing_active && (a2dp_source_cid == connection->avdtp_cid)){
        log_info("discover seps");
        a2dp_source_discover_stream_endpoints(connection->avdtp_cid);
    } else {
        log_info("wait a bit, then discover seps");
        a2dp_source_set_config_timer_start(connection->avdtp_cid);
    }
}

static void a2dp_discover_seps_with_next_waiting_connection(void){
    a2dp_source_state = A2DP_IDLE;

    btstack_linked_list_iterator_t it;
    btstack_linked_list_iterator_init(&it, avdtp_get_connections());
    while (btstack_linked_list_iterator_has_next(&it)){
        avdtp_connection_t * next_connection = (avdtp_connection_t *)btstack_linked_list_iterator_next(&it);
        if (!next_connection->a2dp_source_discover_seps) continue;
        a2dp_start_discovering_seps(next_connection);
    }
}

static void a2dp_source_packet_handler_internal(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
    UNUSED(channel);
    UNUSED(size);

    uint16_t cid;
    avdtp_connection_t * connection;

    uint8_t signal_identifier;
    uint8_t status;
    uint8_t remote_seid;

    if (packet_type != HCI_EVENT_PACKET) return;
    if (hci_event_packet_get_type(packet) != HCI_EVENT_AVDTP_META) return;

    switch (packet[2]){
        case AVDTP_SUBEVENT_SIGNALING_CONNECTION_ESTABLISHED:
            if (sc.local_stream_endpoint == NULL) return;

            cid = avdtp_subevent_signaling_connection_established_get_avdtp_cid(packet);
            connection = avdtp_get_connection_for_avdtp_cid(cid);
            btstack_assert(connection != NULL);

            status = avdtp_subevent_signaling_connection_established_get_status(packet);
            if (status != ERROR_CODE_SUCCESS){
                // notify about connection error only if we're initiator
                if (outgoing_active && (a2dp_source_cid == cid)){
                    log_info("A2DP source signaling connection failed status 0x%02x", status);
                    outgoing_active = false;
                    a2dp_replace_subevent_id_and_emit_cmd(a2dp_source_packet_handler_user, packet, size, A2DP_SUBEVENT_SIGNALING_CONNECTION_ESTABLISHED);
                }
                break;
            }
            log_info("A2DP source signaling connection established avdtp_cid 0x%02x", cid);

            // notify app
            a2dp_replace_subevent_id_and_emit_cmd(a2dp_source_packet_handler_user, packet, size, A2DP_SUBEVENT_SIGNALING_CONNECTION_ESTABLISHED);

            // we already have a valid setup
            if (stream_endpoint_configured) return;

            // start discover seps now if:
            // - outgoing active: signaling for outgoing connection
            // - outgoing not active: incoming connection and no sep discover ongoing

            log_info("outgoing_active %d, current avdtp cid 0x%02x, a2dp_source_state %d", outgoing_active, cid, a2dp_source_state);
            if ((outgoing_active && (a2dp_source_cid == cid)) || (!outgoing_active && (a2dp_source_state == A2DP_IDLE))){
                a2dp_start_discovering_seps(connection);
            } else {
                // post-pone sep discovery
                connection->a2dp_source_discover_seps = true;
            }
            break;

        case AVDTP_SUBEVENT_SIGNALING_SEP_FOUND:
            cid = avdtp_subevent_signaling_sep_found_get_avdtp_cid(packet);
            if (a2dp_source_cid != cid) break;
            if (a2dp_source_state == A2DP_DISCOVER_SEPS) {
                avdtp_sep_t sep;
                sep.seid       = avdtp_subevent_signaling_sep_found_get_remote_seid(packet);;
                sep.in_use     = avdtp_subevent_signaling_sep_found_get_in_use(packet);
                sep.media_type = (avdtp_media_type_t) avdtp_subevent_signaling_sep_found_get_media_type(packet);
                sep.type       = (avdtp_sep_type_t) avdtp_subevent_signaling_sep_found_get_sep_type(packet);
                log_info("A2DP Found sep: remote seid 0x%02x, in_use %d, media type %d, sep type %s, index %d",
                         sep.seid, sep.in_use, sep.media_type, sep.type == AVDTP_SOURCE ? "source" : "sink",
                         num_remote_seps);
                if (sep.type == AVDTP_SINK) {
                    remote_seps[num_remote_seps++] = sep;
                }
            }
            break;

        case AVDTP_SUBEVENT_SIGNALING_SEP_DICOVERY_DONE:
            cid = avdtp_subevent_signaling_sep_dicovery_done_get_avdtp_cid(packet);
            if (a2dp_source_cid != cid) break;
            if (a2dp_source_state != A2DP_DISCOVER_SEPS) break;

            connection = avdtp_get_connection_for_avdtp_cid(cid);
            btstack_assert(connection != NULL);

            if (num_remote_seps > 0){
                a2dp_source_state = A2DP_GET_CAPABILITIES;
                connection->supported_codecs_bitmap = 0;
                sc.active_remote_sep_index = 0;
            } else {
                if (outgoing_active){
                    outgoing_active = false;
                    connection = avdtp_get_connection_for_avdtp_cid(cid);
                    btstack_assert(connection != NULL);
                    a2dp_source_streaming_emit_connection_failed(connection, sc.local_stream_endpoint->sep.seid, ERROR_CODE_CONNECTION_REJECTED_DUE_TO_NO_SUITABLE_CHANNEL_FOUND);
                }

                // continue
                a2dp_discover_seps_with_next_waiting_connection();
            }
            break;

        case AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CAPABILITY:
            cid = avdtp_subevent_signaling_media_codec_sbc_capability_get_avdtp_cid(packet);
            if (a2dp_source_cid != cid) break;
            if (a2dp_source_state == A2DP_GET_CAPABILITIES) {

                log_info("A2DP received SBC capability, received: remote seid 0x%02x (expected: remote seid 0x%02x)",
                    avdtp_subevent_signaling_media_codec_sbc_capability_get_remote_seid(packet), remote_seps[sc.active_remote_sep_index].seid);

                connection = avdtp_get_connection_for_avdtp_cid(cid);
                btstack_assert(connection != NULL);

                // choose SBC config params
                uint8_t sampling_frequency = avdtp_choose_sbc_sampling_frequency(sc.local_stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_sampling_frequency_bitmap(packet));
                uint8_t channel_mode = avdtp_choose_sbc_channel_mode(sc.local_stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_channel_mode_bitmap(packet));
                uint8_t block_length = avdtp_choose_sbc_block_length(sc.local_stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_block_length_bitmap(packet));
                uint8_t subbands = avdtp_choose_sbc_subbands(sc.local_stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_subbands_bitmap(packet));

                uint8_t allocation_method = avdtp_choose_sbc_allocation_method(sc.local_stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_allocation_method_bitmap(packet));
                uint8_t max_bitpool_value = avdtp_choose_sbc_max_bitpool_value(sc.local_stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_max_bitpool_value(packet));
                uint8_t min_bitpool_value = avdtp_choose_sbc_min_bitpool_value(sc.local_stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_min_bitpool_value(packet));

				// set media configuration
				sc.local_stream_endpoint->remote_configuration_bitmap = store_bit16(sc.local_stream_endpoint->remote_configuration_bitmap, AVDTP_MEDIA_CODEC, 1);
				sc.local_stream_endpoint->remote_configuration.media_codec.media_type = AVDTP_AUDIO;
				sc.local_stream_endpoint->remote_configuration.media_codec.media_codec_type = AVDTP_CODEC_SBC;

                // select reserved SBC config buffer
                sc.local_stream_endpoint->remote_configuration.media_codec.media_codec_information = sc.local_stream_endpoint->media_codec_sbc_info;
                sc.local_stream_endpoint->remote_configuration.media_codec.media_codec_information_len = 4;

				// store SBC configuration in reserved field
                sc.local_stream_endpoint->remote_configuration.media_codec.media_codec_information[0] = (sampling_frequency << 4) | channel_mode;
                sc.local_stream_endpoint->remote_configuration.media_codec.media_codec_information[1] = (block_length << 4) | (subbands << 2) | allocation_method;
                sc.local_stream_endpoint->remote_configuration.media_codec.media_codec_information[2] = min_bitpool_value;
                sc.local_stream_endpoint->remote_configuration.media_codec.media_codec_information[3] = max_bitpool_value;

                // suitable Sink SEP found, configure SEP
                sep_found_w2_set_configuration = true;
                connection->supported_codecs_bitmap |= (1 << AVDTP_CODEC_SBC);
            }
            break;

        case AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_OTHER_CAPABILITY:
            log_info("received non SBC codec. not implemented");
            break;

        case AVDTP_SUBEVENT_SIGNALING_MEDIA_TRANSPORT_CAPABILITY:
            log_info("received, but not forwarded: AVDTP_SUBEVENT_SIGNALING_MEDIA_TRANSPORT_CAPABILITY, remote seid 0x%02x", avdtp_subevent_signaling_media_transport_capability_get_remote_seid(packet));
            break;
        case AVDTP_SUBEVENT_SIGNALING_REPORTING_CAPABILITY:
            log_info("received, but not forwarded: AVDTP_SUBEVENT_SIGNALING_REPORTING_CAPABILITY, remote seid 0x%02x", avdtp_subevent_signaling_reporting_capability_get_remote_seid(packet));
            break;
        case AVDTP_SUBEVENT_SIGNALING_RECOVERY_CAPABILITY:
            log_info("received, but not forwarded: AVDTP_SUBEVENT_SIGNALING_RECOVERY_CAPABILITY, remote seid 0x%02x", avdtp_subevent_signaling_recovery_capability_get_remote_seid(packet));
            break;
        case AVDTP_SUBEVENT_SIGNALING_CONTENT_PROTECTION_CAPABILITY:
            log_info("received, but not forwarded: AVDTP_SUBEVENT_SIGNALING_CONTENT_PROTECTION_CAPABILITY, remote seid 0x%02x", avdtp_subevent_signaling_content_protection_capability_get_remote_seid(packet));
            break;
        case AVDTP_SUBEVENT_SIGNALING_HEADER_COMPRESSION_CAPABILITY:
            log_info("received, but not forwarded: AVDTP_SUBEVENT_SIGNALING_HEADER_COMPRESSION_CAPABILITY, remote seid 0x%02x", avdtp_subevent_signaling_header_compression_capability_get_remote_seid(packet));
            break;
        case AVDTP_SUBEVENT_SIGNALING_MULTIPLEXING_CAPABILITY:
            log_info("received, but not forwarded: AVDTP_SUBEVENT_SIGNALING_MULTIPLEXING_CAPABILITY, remote seid 0x%02x", avdtp_subevent_signaling_multiplexing_capability_get_remote_seid(packet));
            break;

        case AVDTP_SUBEVENT_SIGNALING_DELAY_REPORTING_CAPABILITY:
            cid = avdtp_subevent_signaling_delay_reporting_capability_get_avdtp_cid(packet);
            log_info("received AVDTP_SUBEVENT_SIGNALING_DELAY_REPORTING_CAPABILITY, cid 0x%02x, state %d", cid, a2dp_source_state);

            if (a2dp_source_cid != cid) break;
            if (a2dp_source_state != A2DP_GET_CAPABILITIES) break;

            sc.local_stream_endpoint->remote_configuration_bitmap = store_bit16(sc.local_stream_endpoint->remote_configuration_bitmap, AVDTP_DELAY_REPORTING, 1);
            a2dp_replace_subevent_id_and_emit_cmd(a2dp_source_packet_handler_user, packet, size, A2DP_SUBEVENT_SIGNALING_DELAY_REPORTING_CAPABILITY);
            break;

        case AVDTP_SUBEVENT_SIGNALING_CAPABILITIES_DONE:
            cid = avdtp_subevent_signaling_capabilities_done_get_avdtp_cid(packet);
            if (a2dp_source_cid != cid) break;
            if (a2dp_source_state != A2DP_GET_CAPABILITIES) break;

            if (sep_found_w2_set_configuration){
                a2dp_source_state = A2DP_SET_CONFIGURATION;
                sep_found_w2_set_configuration = false;
                break;
            }
            // endpoint was not suitable, check next one
            sc.active_remote_sep_index++;
            if (sc.active_remote_sep_index >= num_remote_seps){
                // we didn't find a suitable SBC stream endpoint, sorry.
                if (outgoing_active){
                    outgoing_active = false;
                    connection = avdtp_get_connection_for_avdtp_cid(cid);
                    btstack_assert(connection != NULL);
                    a2dp_source_streaming_emit_connection_failed(connection, sc.local_stream_endpoint->sep.seid, ERROR_CODE_CONNECTION_REJECTED_DUE_TO_NO_SUITABLE_CHANNEL_FOUND);
                }
                a2dp_discover_seps_with_next_waiting_connection();
            }
            break;

        case AVDTP_SUBEVENT_SIGNALING_DELAY_REPORT:
            cid = avdtp_subevent_signaling_delay_report_get_avdtp_cid(packet);
            if (a2dp_source_cid != cid) break;
            a2dp_replace_subevent_id_and_emit_cmd(a2dp_source_packet_handler_user, packet, size, A2DP_SUBEVENT_SIGNALING_DELAY_REPORT);
            break;

        case AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CONFIGURATION:
            cid = avdtp_subevent_signaling_media_codec_sbc_configuration_get_avdtp_cid(packet);

            if ((a2dp_source_cid == cid) && (a2dp_source_state == A2DP_W4_SET_CONFIGURATION)){
				// outgoing: discovery and config of remote sink sep successful, trigger stream open
				a2dp_source_state = A2DP_W2_OPEN_STREAM_WITH_SEID;
            } else {
				// incoming: accept cid and wait for stream open
				a2dp_source_cid = cid;
				a2dp_source_state = A2DP_W4_OPEN_STREAM_WITH_SEID;
            }

            // config set: stop timer
			a2dp_source_set_config_timer_stop();
            stream_endpoint_configured = true;

            sc.sampling_frequency = avdtp_subevent_signaling_media_codec_sbc_configuration_get_sampling_frequency(packet);
            sc.channel_mode = avdtp_subevent_signaling_media_codec_sbc_configuration_get_channel_mode(packet);
            sc.block_length = avdtp_subevent_signaling_media_codec_sbc_configuration_get_block_length(packet);
            sc.subbands = avdtp_subevent_signaling_media_codec_sbc_configuration_get_subbands(packet);
            sc.allocation_method = avdtp_subevent_signaling_media_codec_sbc_configuration_get_allocation_method(packet);
            sc.max_bitpool_value = avdtp_subevent_signaling_media_codec_sbc_configuration_get_max_bitpool_value(packet);
            sc.min_bitpool_value = avdtp_subevent_signaling_media_codec_sbc_configuration_get_min_bitpool_value(packet);

            log_info("A2DP received SBC Config: sample rate %u, max bitpool %u., remote seid 0x%02x", sc.sampling_frequency, sc.max_bitpool_value, avdtp_subevent_signaling_media_codec_sbc_configuration_get_remote_seid(packet));
            a2dp_replace_subevent_id_and_emit_cmd(a2dp_source_packet_handler_user, packet, size, A2DP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CONFIGURATION);
            break;

        case AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_OTHER_CONFIGURATION:
            break;

        case AVDTP_SUBEVENT_STREAMING_CAN_SEND_MEDIA_PACKET_NOW:
            a2dp_replace_subevent_id_and_emit_cmd(a2dp_source_packet_handler_user, packet, size, A2DP_SUBEVENT_STREAMING_CAN_SEND_MEDIA_PACKET_NOW);
            break;

        case AVDTP_SUBEVENT_STREAMING_CONNECTION_ESTABLISHED:
            cid = avdtp_subevent_streaming_connection_established_get_avdtp_cid(packet);
            if (a2dp_source_cid != cid) break;
            if (a2dp_source_state != A2DP_W4_OPEN_STREAM_WITH_SEID) break;

			outgoing_active = false;
            status = avdtp_subevent_streaming_connection_established_get_status(packet);
            if (status != ERROR_CODE_SUCCESS){
                log_info("A2DP source streaming connection could not be established, avdtp_cid 0x%02x, status 0x%02x ---", cid, status);
                a2dp_replace_subevent_id_and_emit_cmd(a2dp_source_packet_handler_user, packet, size, A2DP_SUBEVENT_STREAM_ESTABLISHED);
                break;
            }

            log_info("A2DP source streaming connection established --- avdtp_cid 0x%02x, local seid 0x%02x, remote seid 0x%02x", cid,
                avdtp_subevent_streaming_connection_established_get_local_seid(packet),
                avdtp_subevent_streaming_connection_established_get_remote_seid(packet));
            a2dp_source_state = A2DP_STREAMING_OPENED;
            a2dp_replace_subevent_id_and_emit_cmd(a2dp_source_packet_handler_user, packet, size, A2DP_SUBEVENT_STREAM_ESTABLISHED);
            break;

        case AVDTP_SUBEVENT_SIGNALING_ACCEPT:
            cid = avdtp_subevent_signaling_accept_get_avdtp_cid(packet);

			// reset discovery timer while remote is active
			if (avdtp_subevent_signaling_accept_get_is_initiator(packet) == 0) {
				uint16_t avdtp_cid = (uint16_t)(uintptr_t) btstack_run_loop_get_timer_context(&a2dp_source_set_config_timer);
				if ((avdtp_cid == 0) || (avdtp_cid != cid)) break;
				log_info("Reset discovery timer");
				a2dp_source_set_config_timer_start(avdtp_cid);
				break;
			}

            if (a2dp_source_cid != cid) break;

            signal_identifier = avdtp_subevent_signaling_accept_get_signal_identifier(packet);

            log_info("A2DP cmd %s accepted, global state %d, cid 0x%02x", avdtp_si2str(signal_identifier), a2dp_source_state, cid);

            switch (a2dp_source_state){
                case A2DP_GET_CAPABILITIES:
                    remote_seid = remote_seps[sc.active_remote_sep_index].seid;
                    log_info("A2DP get capabilities for remote seid 0x%02x", remote_seid);
                    avdtp_source_get_all_capabilities(cid, remote_seid);
                    return;

                case A2DP_SET_CONFIGURATION:
                    remote_seid = remote_seps[sc.active_remote_sep_index].seid;
                    log_info("A2DP initiate set configuration locally and wait for response ... local seid 0x%02x, remote seid 0x%02x", avdtp_stream_endpoint_seid(sc.local_stream_endpoint), remote_seid);
                    a2dp_source_state = A2DP_W4_SET_CONFIGURATION;
                    avdtp_source_set_configuration(cid, avdtp_stream_endpoint_seid(sc.local_stream_endpoint), remote_seid, sc.local_stream_endpoint->remote_configuration_bitmap, sc.local_stream_endpoint->remote_configuration);
                    return;

                case A2DP_W2_OPEN_STREAM_WITH_SEID:
                    log_info("A2DP open stream ... local seid 0x%02x, active remote seid 0x%02x", avdtp_stream_endpoint_seid(sc.local_stream_endpoint), sc.local_stream_endpoint->remote_sep.seid);
                    a2dp_source_state = A2DP_W4_OPEN_STREAM_WITH_SEID;
                    avdtp_source_open_stream(cid, avdtp_stream_endpoint_seid(sc.local_stream_endpoint), sc.local_stream_endpoint->remote_sep.seid);
                    break;

                case A2DP_W2_RECONFIGURE_WITH_SEID:
                    log_info("A2DP reconfigured ... local seid 0x%02x, active remote seid 0x%02x", avdtp_stream_endpoint_seid(sc.local_stream_endpoint), sc.local_stream_endpoint->remote_sep.seid);
                    a2dp_signaling_emit_reconfigured(cid, avdtp_stream_endpoint_seid(sc.local_stream_endpoint), ERROR_CODE_SUCCESS);
                    a2dp_source_state = A2DP_STREAMING_OPENED;
                    break;

                case A2DP_STREAMING_OPENED:
                    switch (signal_identifier){
                        case  AVDTP_SI_START:
                            a2dp_emit_stream_event(a2dp_source_packet_handler_user, cid, avdtp_stream_endpoint_seid(sc.local_stream_endpoint), A2DP_SUBEVENT_STREAM_STARTED);
                            break;
                        case AVDTP_SI_SUSPEND:
                            a2dp_emit_stream_event(a2dp_source_packet_handler_user, cid, avdtp_stream_endpoint_seid(sc.local_stream_endpoint), A2DP_SUBEVENT_STREAM_SUSPENDED);
                            break;
                        case AVDTP_SI_ABORT:
                        case AVDTP_SI_CLOSE:
                            a2dp_emit_stream_event(a2dp_source_packet_handler_user, cid, avdtp_stream_endpoint_seid(sc.local_stream_endpoint), A2DP_SUBEVENT_STREAM_STOPPED);
                            break;
                        default:
                            break;
                    }
                    break;

                default:
                    break;
            }
            break;

        case AVDTP_SUBEVENT_SIGNALING_REJECT:
            cid = avdtp_subevent_signaling_reject_get_avdtp_cid(packet);
            if (a2dp_source_cid != cid) break;
            if (avdtp_subevent_signaling_reject_get_is_initiator(packet) == 0) break;

            a2dp_source_state = A2DP_CONNECTED;
            a2dp_replace_subevent_id_and_emit_cmd(a2dp_source_packet_handler_user, packet, size, A2DP_SUBEVENT_COMMAND_REJECTED);
            break;

        case AVDTP_SUBEVENT_SIGNALING_GENERAL_REJECT:
            cid = avdtp_subevent_signaling_general_reject_get_avdtp_cid(packet);
            if (a2dp_source_cid != cid) break;
            if (avdtp_subevent_signaling_general_reject_get_is_initiator(packet) == 0) break;

            a2dp_source_state = A2DP_CONNECTED;
            a2dp_replace_subevent_id_and_emit_cmd(a2dp_source_packet_handler_user, packet, size, A2DP_SUBEVENT_COMMAND_REJECTED);
            break;

        case AVDTP_SUBEVENT_STREAMING_CONNECTION_RELEASED:
            cid = avdtp_subevent_streaming_connection_released_get_avdtp_cid(packet);
            if (a2dp_source_cid != cid) break;

            a2dp_source_state = A2DP_CONFIGURED;
            a2dp_replace_subevent_id_and_emit_cmd(a2dp_source_packet_handler_user, packet, size, A2DP_SUBEVENT_STREAM_RELEASED);
            break;

        case AVDTP_SUBEVENT_SIGNALING_CONNECTION_RELEASED:
            cid = avdtp_subevent_signaling_connection_released_get_avdtp_cid(packet);
            // connect/release are passed on to app
            if (a2dp_source_cid == cid){
                stream_endpoint_configured = false;
                a2dp_source_state = A2DP_IDLE;
                a2dp_source_cid = 0;
            }
            a2dp_replace_subevent_id_and_emit_cmd(a2dp_source_packet_handler_user, packet, size, A2DP_SUBEVENT_SIGNALING_CONNECTION_RELEASED);
            break;

        default:
            break;
    }
}
void a2dp_source_register_packet_handler(btstack_packet_handler_t callback){
    btstack_assert(callback != NULL);

    avdtp_source_register_packet_handler(&a2dp_source_packet_handler_internal);
    a2dp_source_packet_handler_user = callback;
}

void a2dp_source_init(void){
    avdtp_source_init();
}

avdtp_stream_endpoint_t * a2dp_source_create_stream_endpoint(avdtp_media_type_t media_type, avdtp_media_codec_type_t media_codec_type,
															 uint8_t * codec_capabilities, uint16_t codec_capabilities_len,
															 uint8_t * codec_configuration, uint16_t codec_configuration_len){
    avdtp_stream_endpoint_t * local_stream_endpoint = avdtp_source_create_stream_endpoint(AVDTP_SOURCE, media_type);
    if (!local_stream_endpoint){
        return NULL;
    }
    avdtp_source_register_media_transport_category(avdtp_stream_endpoint_seid(local_stream_endpoint));
    avdtp_source_register_media_codec_category(avdtp_stream_endpoint_seid(local_stream_endpoint), media_type, media_codec_type,
        codec_capabilities, codec_capabilities_len);
	avdtp_source_register_delay_reporting_category(avdtp_stream_endpoint_seid(local_stream_endpoint));

	// store user codec configuration buffer
	local_stream_endpoint->media_codec_configuration_info = codec_configuration;
	local_stream_endpoint->media_codec_configuration_len  = codec_configuration_len;

    sc.local_stream_endpoint = local_stream_endpoint;
    return local_stream_endpoint;
}

void a2dp_source_finalize_stream_endpoint(avdtp_stream_endpoint_t * stream_endpoint){
    avdtp_source_finalize_stream_endpoint(stream_endpoint);
}

uint8_t a2dp_source_establish_stream(bd_addr_t remote_addr, uint8_t loc_seid, uint16_t * avdtp_cid){
    if (outgoing_active || stream_endpoint_configured) {
        return ERROR_CODE_COMMAND_DISALLOWED;
    }

    sc.local_stream_endpoint = avdtp_get_stream_endpoint_for_seid(loc_seid);
    if (!sc.local_stream_endpoint){
        return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
    }

    uint16_t outgoing_cid;

    outgoing_active = true;
    uint8_t status = avdtp_source_connect(remote_addr, &outgoing_cid);
    if (status != ERROR_CODE_SUCCESS) {
        // if there's already a connection for for remote addr, avdtp_source_connect fails,
        // but the stream will get set-up nevertheless
        outgoing_active = false;
        return status;
    }

    // stop sep discovery for other
    if (a2dp_source_state != A2DP_IDLE){
        avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(a2dp_source_cid);
        if (connection != NULL){
            // sdp discovery has started: post-pone action, reserve sep discovery mechanism
            connection->a2dp_source_discover_seps = true;
        }
    }

    // setup state
    a2dp_source_state = A2DP_W4_CONNECTED;
    a2dp_source_cid   = outgoing_cid;
    *avdtp_cid = outgoing_cid;

    return ERROR_CODE_SUCCESS;
}

uint8_t a2dp_source_disconnect(uint16_t avdtp_cid){
    return avdtp_disconnect(avdtp_cid);
}

uint8_t a2dp_source_reconfigure_stream_sampling_frequency(uint16_t avdtp_cid, uint32_t sampling_frequency){
    btstack_assert(sc.local_stream_endpoint != NULL);

    if (a2dp_source_cid != avdtp_cid){
        return ERROR_CODE_COMMAND_DISALLOWED;
    }

    avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
    if (connection == NULL){
        return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
    }

    if (a2dp_source_state != A2DP_STREAMING_OPENED) {
        return ERROR_CODE_COMMAND_DISALLOWED;
    }

    log_info("Reconfigure avdtp_cid 0x%02x", avdtp_cid);

    (void)memcpy(sc.local_stream_endpoint->media_codec_sbc_info,
                 sc.local_stream_endpoint->remote_sep.configuration.media_codec.media_codec_information,
                 4);

    // update sampling frequency
    uint8_t config = sc.local_stream_endpoint->media_codec_sbc_info[0] & 0x0f;
    switch (sampling_frequency){
        case 48000:
            config |= (AVDTP_SBC_48000 << 4);
            break;
        case 44100:
            config |= (AVDTP_SBC_44100 << 4);
            break;
        case 32000:
            config |= (AVDTP_SBC_32000 << 4);
            break;
        case 16000:
            config |= (AVDTP_SBC_16000 << 4);
            break;
        default:
            log_error("Unsupported sampling frequency %u", (int) sampling_frequency);
            return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
    }
    sc.local_stream_endpoint->media_codec_sbc_info[0] = config;

    avdtp_capabilities_t new_configuration;
    new_configuration.media_codec.media_type = AVDTP_AUDIO;
    new_configuration.media_codec.media_codec_type = AVDTP_CODEC_SBC;
    new_configuration.media_codec.media_codec_information_len = 4;
    new_configuration.media_codec.media_codec_information = sc.local_stream_endpoint->media_codec_sbc_info;

    // start reconfigure
    a2dp_source_state = A2DP_W2_RECONFIGURE_WITH_SEID;

    return avdtp_source_reconfigure(
        avdtp_cid,
        avdtp_stream_endpoint_seid(sc.local_stream_endpoint),
        sc.local_stream_endpoint->remote_sep.seid,
        1 << AVDTP_MEDIA_CODEC,
        new_configuration
    );
}

uint8_t a2dp_source_start_stream(uint16_t avdtp_cid, uint8_t local_seid){
    return avdtp_start_stream(avdtp_cid, local_seid);
}

uint8_t a2dp_source_pause_stream(uint16_t avdtp_cid, uint8_t local_seid){
    return avdtp_suspend_stream(avdtp_cid, local_seid);
}

void a2dp_source_stream_endpoint_request_can_send_now(uint16_t avdtp_cid, uint8_t local_seid){
    avdtp_source_stream_endpoint_request_can_send_now(avdtp_cid, local_seid);
}

int a2dp_max_media_payload_size(uint16_t avdtp_cid, uint8_t local_seid){
    return avdtp_max_media_payload_size(avdtp_cid, local_seid);
}

int a2dp_source_stream_send_media_payload(uint16_t avdtp_cid, uint8_t local_seid, uint8_t * storage, int num_bytes_to_copy, uint8_t num_frames, uint8_t marker){
    return avdtp_source_stream_send_media_payload(avdtp_cid, local_seid, storage, num_bytes_to_copy, num_frames, marker);
}