xref: /btstack/src/classic/avrcp_controller.c (revision 45a58b3093f5320b8ffda59b52081d2b540d3217)
1 /*
2  * Copyright (C) 2016 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the copyright holders nor the names of
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
17  *    personal benefit and not for any commercial purpose or for
18  *    monetary gain.
19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
24  * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
30  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * Please inquire about commercial licensing options at
34  * [email protected]
35  *
36  */
37 
38 #define __BTSTACK_FILE__ "avrcp_controller.c"
39 
40 #include <stdint.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <inttypes.h>
45 
46 #include "btstack.h"
47 #include "classic/avrcp.h"
48 #include "classic/avrcp_controller.h"
49 
50 // made public in avrcp_controller.h
51 avrcp_context_t avrcp_controller_context;
52 
53 void avrcp_controller_create_sdp_record(uint8_t * service, uint32_t service_record_handle, uint8_t browsing, uint16_t supported_features, const char * service_name, const char * service_provider_name){
54     avrcp_create_sdp_record(1, service, service_record_handle, browsing, supported_features, service_name, service_provider_name);
55 }
56 
57 static void avrcp_emit_repeat_and_shuffle_mode(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t ctype, avrcp_repeat_mode_t repeat_mode, avrcp_shuffle_mode_t shuffle_mode){
58     if (!callback) return;
59     uint8_t event[8];
60     int pos = 0;
61     event[pos++] = HCI_EVENT_AVRCP_META;
62     event[pos++] = sizeof(event) - 2;
63     event[pos++] = AVRCP_SUBEVENT_SHUFFLE_AND_REPEAT_MODE;
64     little_endian_store_16(event, pos, avrcp_cid);
65     pos += 2;
66     event[pos++] = ctype;
67     event[pos++] = repeat_mode;
68     event[pos++] = shuffle_mode;
69     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
70 }
71 
72 static void avrcp_emit_operation_status(btstack_packet_handler_t callback, uint8_t subevent, uint16_t avrcp_cid, uint8_t ctype, uint8_t operation_id){
73     if (!callback) return;
74     uint8_t event[7];
75     int pos = 0;
76     event[pos++] = HCI_EVENT_AVRCP_META;
77     event[pos++] = sizeof(event) - 2;
78     event[pos++] = subevent;
79     little_endian_store_16(event, pos, avrcp_cid);
80     pos += 2;
81     event[pos++] = ctype;
82     event[pos++] = operation_id;
83     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
84 }
85 
86 static void avrcp_press_and_hold_timeout_handler(btstack_timer_source_t * timer){
87     UNUSED(timer);
88     avrcp_connection_t * connection = btstack_run_loop_get_timer_context(timer);
89     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
90     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
91     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
92     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
93 }
94 
95 static void avrcp_press_and_hold_timer_start(avrcp_connection_t * connection){
96     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
97     btstack_run_loop_set_timer_handler(&connection->press_and_hold_cmd_timer, avrcp_press_and_hold_timeout_handler);
98     btstack_run_loop_set_timer_context(&connection->press_and_hold_cmd_timer, connection);
99     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
100     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
101 }
102 
103 static void avrcp_press_and_hold_timer_stop(avrcp_connection_t * connection){
104     connection->continuous_fast_forward_cmd = 0;
105     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
106 }
107 
108 static uint8_t request_pass_through_release_control_cmd(avrcp_connection_t * connection){
109     connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
110     if (connection->continuous_fast_forward_cmd){
111         avrcp_press_and_hold_timer_stop(connection);
112     }
113     connection->cmd_operands[0] = 0x80 | connection->cmd_operands[0];
114     connection->transaction_label++;
115     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
116     return ERROR_CODE_SUCCESS;
117 }
118 
119 static inline uint8_t request_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed, uint8_t continuous_fast_forward_cmd, avrcp_context_t * context){
120     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, context);
121     if (!connection){
122         log_error("avrcp: could not find a connection.");
123         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
124     }
125     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
126     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
127     connection->command_opcode =  AVRCP_CMD_OPCODE_PASS_THROUGH;
128     connection->command_type = AVRCP_CTYPE_CONTROL;
129     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
130     connection->subunit_id =   AVRCP_SUBUNIT_ID;
131     connection->cmd_operands_length = 0;
132 
133     connection->continuous_fast_forward_cmd = continuous_fast_forward_cmd;
134     connection->cmd_operands_length = 2;
135     connection->cmd_operands[0] = opid;
136     if (playback_speed > 0){
137         connection->cmd_operands[2] = playback_speed;
138         connection->cmd_operands_length++;
139     }
140     connection->cmd_operands[1] = connection->cmd_operands_length - 2;
141 
142     if (connection->continuous_fast_forward_cmd){
143         avrcp_press_and_hold_timer_start(connection);
144     }
145 
146     connection->transaction_label++;
147     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
148     return ERROR_CODE_SUCCESS;
149 }
150 
151 static uint8_t request_single_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
152     return request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, 0, &avrcp_controller_context);
153 }
154 
155 static uint8_t request_continuous_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
156     return request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, 1, &avrcp_controller_context);
157 }
158 
159 #define AVRCP_CMD_BUFFER_SIZE 30
160 static uint16_t avrcp_get_max_payload_size_for_packet_type(avrcp_packet_type_t packet_type){
161     switch (packet_type){
162         case AVRCP_SINGLE_PACKET:
163             return AVRCP_CMD_BUFFER_SIZE - 3;
164         case AVRCP_START_PACKET:
165             return AVRCP_CMD_BUFFER_SIZE - 4;
166         case AVRCP_CONTINUE_PACKET:
167         case AVRCP_END_PACKET:
168             return AVRCP_CMD_BUFFER_SIZE - 1;
169     }
170     return 0;
171 }
172 
173 static int avrcp_send_cmd(avrcp_connection_t * connection, avrcp_packet_type_t packet_type){
174     uint8_t command[AVRCP_CMD_BUFFER_SIZE];
175     int pos = 0;
176     uint16_t max_bytes = sizeof(command) - 1;
177 
178     // transport header
179     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
180     command[pos++] = (connection->transaction_label << 4) | (packet_type << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
181 
182     if (packet_type == AVRCP_START_PACKET){
183         // num packets: (3 bytes overhead (PID, num packets) + command) / (MTU - transport header)
184         command[pos++] = ((connection->cmd_operands_fragmented_len + 3 - 1) / (AVRCP_CMD_BUFFER_SIZE - 1)) + 1;
185         max_bytes -= 3;
186     }
187 
188     if (packet_type == AVRCP_SINGLE_PACKET || packet_type == AVRCP_START_PACKET){
189         // Profile IDentifier (PID)
190         command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
191         command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
192 
193         // command_type
194         command[pos++] = connection->command_type;
195         // subunit_type | subunit ID
196         command[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
197         // opcode
198         command[pos++] = (uint8_t)connection->command_opcode;
199     }
200 
201     if (packet_type == AVRCP_SINGLE_PACKET){
202         // operands
203         memcpy(command+pos, connection->cmd_operands, connection->cmd_operands_length);
204         pos += connection->cmd_operands_length;
205     } else {
206         uint16_t bytes_to_copy = btstack_min(connection->cmd_operands_fragmented_len-connection->cmd_operands_fragmented_pos, max_bytes);
207         memcpy(command+pos, &connection->cmd_operands_fragmented_buffer[connection->cmd_operands_fragmented_pos], bytes_to_copy);
208         pos += bytes_to_copy;
209         connection->cmd_operands_fragmented_pos += bytes_to_copy;
210     }
211 
212     return l2cap_send(connection->l2cap_signaling_cid, command, pos);
213 }
214 
215 static int avrcp_register_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t event_id){
216     if (connection->notifications_to_deregister & (1 << event_id)) return 0;
217     if (connection->notifications_enabled & (1 << event_id)) return 0;
218     if (connection->notifications_to_register & (1 << event_id)) return 0;
219     connection->notifications_to_register |= (1 << event_id);
220     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
221     return 1;
222 }
223 
224 static void avrcp_prepare_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t event_id){
225     connection->transaction_label++;
226     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
227     connection->command_type = AVRCP_CTYPE_NOTIFY;
228     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
229     connection->subunit_id = AVRCP_SUBUNIT_ID;
230     int pos = 0;
231     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
232     pos += 3;
233     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REGISTER_NOTIFICATION;
234     connection->cmd_operands[pos++] = 0;                     // reserved(upper 6) | packet_type -> 0
235     big_endian_store_16(connection->cmd_operands, pos, 5);     // parameter length
236     pos += 2;
237     connection->cmd_operands[pos++] = event_id;
238     big_endian_store_32(connection->cmd_operands, pos, 0);
239     pos += 4;
240     connection->cmd_operands_length = pos;
241     // AVRCP_SPEC_V14.pdf 166
242     // answer page 61
243 }
244 
245 
246 static void avrcp_parser_reset(avrcp_connection_t * connection){
247     connection->list_offset = 0;
248     connection->num_attributes = 0;
249     connection->num_parsed_attributes = 0;
250     connection->parser_attribute_header_pos = 0;
251     connection->num_received_fragments = 0;
252     connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
253 }
254 
255 static void avrcp_controller_emit_now_playing_info_event_done(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t ctype, uint8_t status){
256     uint8_t event[7];
257     int pos = 0;
258     event[pos++] = HCI_EVENT_AVRCP_META;
259     event[pos++] = sizeof(event) - 2;
260     event[pos++] = AVRCP_SUBEVENT_NOW_PLAYING_INFO_DONE;
261     little_endian_store_16(event, pos, avrcp_cid);
262     pos += 2;
263     event[pos++] = ctype;
264     event[pos++] = status;
265     // printf_hexdump(event, pos);
266     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
267 }
268 
269 static void avrcp_controller_emit_now_playing_info_event(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t ctype, avrcp_media_attribute_id_t attr_id, uint8_t * value, uint16_t value_len){
270     uint8_t event[HCI_EVENT_BUFFER_SIZE];
271     int pos = 0;
272     event[pos++] = HCI_EVENT_AVRCP_META;
273     // reserve one byte for subevent type and data len
274     int data_len_pos = pos;
275     pos++;
276     int subevent_type_pos = pos;
277     pos++;
278     little_endian_store_16(event, pos, avrcp_cid);
279     pos += 2;
280     event[pos++] = ctype;
281 
282     switch (attr_id){
283         case AVRCP_MEDIA_ATTR_TITLE:
284             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TITLE_INFO;
285             event[pos++] = value_len;
286             memcpy(event+pos, value, value_len);
287             break;
288         case AVRCP_MEDIA_ATTR_ARTIST:
289             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ARTIST_INFO;
290             event[pos++] = value_len;
291             memcpy(event+pos, value, value_len);
292             break;
293         case AVRCP_MEDIA_ATTR_ALBUM:
294             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ALBUM_INFO;
295             event[pos++] = value_len;
296             memcpy(event+pos, value, value_len);
297             break;
298         case AVRCP_MEDIA_ATTR_GENRE:
299             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_GENRE_INFO;
300             event[pos++] = value_len;
301             memcpy(event+pos, value, value_len);
302             break;
303         case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
304             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_SONG_LENGTH_MS_INFO;
305             if (value){
306                 little_endian_store_32(event, pos, btstack_atoi((char *)value));
307             } else {
308                 little_endian_store_32(event, pos, 0);
309             }
310             pos += 4;
311             break;
312         case AVRCP_MEDIA_ATTR_TRACK:
313             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TRACK_INFO;
314             if (value){
315                 event[pos++] = btstack_atoi((char *)value);
316             } else {
317                 event[pos++] = 0;
318             }
319             break;
320         case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
321             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TOTAL_TRACKS_INFO;
322             if (value){
323                 event[pos++] = btstack_atoi((char *)value);
324             } else {
325                 event[pos++] = 0;
326             }
327             break;
328         default:
329             break;
330     }
331     event[data_len_pos] = pos - 2;
332     // printf("send attr len %d,  value %s\n", value_len, value);
333     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
334 }
335 
336 static void avrcp_parser_process_byte(uint8_t byte, avrcp_connection_t * connection, avrcp_command_type_t ctype){
337     uint16_t attribute_total_value_len;
338     uint32_t attribute_id;
339     switch(connection->parser_state){
340         case AVRCP_PARSER_GET_ATTRIBUTE_HEADER:
341             connection->parser_attribute_header[connection->parser_attribute_header_pos++] = byte;
342             connection->list_offset++;
343 
344             if (connection->parser_attribute_header_pos < AVRCP_ATTRIBUTE_HEADER_LEN) return;
345 
346             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
347             connection->attribute_value_len = btstack_min(attribute_total_value_len, AVRCP_MAX_ATTRIBUTTE_SIZE);
348             if (connection->attribute_value_len > 0){
349                 // get ready for attribute value
350                 connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_VALUE;
351                 return;
352             }
353 
354             // emit empty attribute
355             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
356             avrcp_controller_emit_now_playing_info_event(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, attribute_id, connection->attribute_value, connection->attribute_value_len);
357 
358             // done, see below
359             break;
360 
361         case AVRCP_PARSER_GET_ATTRIBUTE_VALUE:
362             connection->attribute_value[connection->attribute_value_offset++] = byte;
363             connection->list_offset++;
364 
365             if (connection->attribute_value_offset < connection->attribute_value_len) return;
366 
367             // emit (potentially partial) attribute
368             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
369             avrcp_controller_emit_now_playing_info_event(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, attribute_id, connection->attribute_value, connection->attribute_value_len);
370 
371             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
372             if (connection->attribute_value_offset < attribute_total_value_len){
373                 // ignore rest of attribute
374                 connection->parser_state = AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE;
375                 return;
376             }
377 
378             // done, see below
379             break;
380 
381         case AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE:
382             connection->attribute_value_offset++;
383             connection->list_offset++;
384 
385             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
386             if (connection->attribute_value_offset < attribute_total_value_len) return;
387 
388             // done, see below
389             break;
390 
391         default:
392             return;
393     }
394 
395     // attribute fully read, check if more to come
396     if (connection->list_offset < connection->list_size){
397         // more to come, reset parser
398         connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
399         connection->parser_attribute_header_pos = 0;
400     } else {
401         // fully done
402         avrcp_parser_reset(connection);
403         avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 0);
404     }
405 }
406 
407 static void avrcp_source_parse_and_emit_element_attrs(uint8_t * packet, uint16_t num_bytes_to_read, avrcp_connection_t * connection, avrcp_command_type_t ctype){
408     int i;
409     for (i=0;i<num_bytes_to_read;i++){
410         avrcp_parser_process_byte(packet[i], connection, ctype);
411     }
412 }
413 
414 static uint8_t avrcp_controller_request_abort_continuation(avrcp_connection_t * connection){
415     connection->state = AVCTP_W2_SEND_COMMAND;
416     connection->transaction_label++;
417     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
418     connection->command_type = AVRCP_CTYPE_CONTROL;
419     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
420     connection->subunit_id = AVRCP_SUBUNIT_ID;
421     int pos = 0;
422     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
423     pos += 3;
424     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE; // PDU ID
425     connection->cmd_operands[pos++] = 0;
426     // Parameter Length
427     connection->cmd_operands_length = 8;
428     big_endian_store_16(connection->cmd_operands, pos, 1);
429     pos += 2;
430     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
431     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
432     return ERROR_CODE_SUCCESS;
433 }
434 
435 
436 static uint8_t avrcp_controller_request_continue_response(avrcp_connection_t * connection){
437     connection->state = AVCTP_W2_SEND_COMMAND;
438     connection->transaction_label++;
439     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
440     connection->command_type = AVRCP_CTYPE_CONTROL;
441     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
442     connection->subunit_id = AVRCP_SUBUNIT_ID;
443     int pos = 0;
444     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
445     pos += 3;
446     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE; // PDU ID
447     connection->cmd_operands[pos++] = 0;
448     // Parameter Length
449     connection->cmd_operands_length = 8;
450     big_endian_store_16(connection->cmd_operands, pos, 1);
451     pos += 2;
452     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
453     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
454     return ERROR_CODE_SUCCESS;
455 }
456 
457 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t *packet, uint16_t size){
458     uint8_t operands[20];
459     uint8_t opcode;
460     int     pos = 3;
461     // uint8_t transport_header = packet[0];
462     // uint8_t transaction_label = transport_header >> 4;
463     // uint8_t packet_type = (transport_header & 0x0F) >> 2;
464     // uint8_t frame_type = (transport_header & 0x03) >> 1;
465     // uint8_t ipid = transport_header & 0x01;
466     // uint8_t byte_value = packet[2];
467     // uint16_t pid = (byte_value << 8) | packet[2];
468 
469     avrcp_command_type_t ctype = (avrcp_command_type_t) packet[pos++];
470     uint8_t byte_value = packet[pos++];
471     avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (byte_value >> 3);
472     avrcp_subunit_type_t subunit_id = (avrcp_subunit_type_t)   (byte_value & 0x07);
473     opcode = packet[pos++];
474 
475     // printf("    Transport header 0x%02x (transaction_label %d, packet_type %d, frame_type %d, ipid %d), pid 0x%4x\n",
476     //     transport_header, transaction_label, packet_type, frame_type, ipid, pid);
477     // // printf_hexdump(packet+pos, size-pos);
478 
479     uint8_t pdu_id;
480     uint16_t param_length;
481     switch (avrcp_cmd_opcode(packet,size)){
482         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:{
483             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
484             connection->state = AVCTP_CONNECTION_OPENED;
485             // operands:
486             memcpy(operands, packet+pos, 5);
487             uint8_t unit_type = operands[1] >> 3;
488             uint8_t max_subunit_ID = operands[1] & 0x07;
489             log_info("    SUBUNIT INFO response: ctype 0x%02x (0C), subunit_type 0x%02x (1F), subunit_id 0x%02x (07), opcode 0x%02x (30), unit_type 0x%02x, max_subunit_ID %d", ctype, subunit_type, subunit_id, opcode, unit_type, max_subunit_ID);
490             break;
491         }
492         case AVRCP_CMD_OPCODE_UNIT_INFO:{
493             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
494             connection->state = AVCTP_CONNECTION_OPENED;
495             // operands:
496             memcpy(operands, packet+pos, 5);
497             uint8_t unit_type = operands[1] >> 3;
498             uint8_t unit = operands[1] & 0x07;
499             uint32_t company_id = operands[2] << 16 | operands[3] << 8 | operands[4];
500             log_info("    UNIT INFO response: ctype 0x%02x (0C), subunit_type 0x%02x (1F), subunit_id 0x%02x (07), opcode 0x%02x (30), unit_type 0x%02x, unit %d, company_id 0x%06" PRIx32,
501                 ctype, subunit_type, subunit_id, opcode, unit_type, unit, company_id);
502             break;
503         }
504         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
505             if (size - pos < 7) {
506                 log_error("avrcp: wrong packet size");
507                 return;
508             };
509             // operands:
510             memcpy(operands, packet+pos, 7);
511             pos += 7;
512             // uint32_t company_id = operands[0] << 16 | operands[1] << 8 | operands[2];
513             pdu_id = operands[3];
514 
515             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE && pdu_id != AVRCP_PDU_ID_REGISTER_NOTIFICATION){
516                 log_info("AVRCP_CMD_OPCODE_VENDOR_DEPENDENT state %d", connection->state);
517                 return;
518             }
519             connection->state = AVCTP_CONNECTION_OPENED;
520 
521 
522             // uint8_t unit_type = operands[4] >> 3;
523             // uint8_t unit = operands[4] & 0x07;
524             param_length = big_endian_read_16(operands, 5);
525 
526             // printf("    VENDOR DEPENDENT response: ctype 0x%02x (0C), subunit_type 0x%02x (1F), subunit_id 0x%02x (07), opcode 0x%02x (30), unit_type 0x%02x, unit %d, company_id 0x%06x\n",
527             //     ctype, subunit_type, subunit_id, opcode, unit_type, unit, company_id );
528 
529             // if (ctype == AVRCP_CTYPE_RESPONSE_INTERIM) return;
530             log_info("        VENDOR DEPENDENT response: pdu id 0x%02x, param_length %d, status %s", pdu_id, param_length, avrcp_ctype2str(ctype));
531             switch (pdu_id){
532                 case AVRCP_PDU_ID_GetCurrentPlayerApplicationSettingValue:{
533                     uint8_t num_attributes = packet[pos++];
534                     int i;
535                     avrcp_repeat_mode_t  repeat_mode =  AVRCP_REPEAT_MODE_INVALID;
536                     avrcp_shuffle_mode_t shuffle_mode = AVRCP_SHUFFLE_MODE_INVALID;
537                     for (i = 0; i < num_attributes; i++){
538                         uint8_t attribute_id    = packet[pos++];
539                         uint8_t value = packet[pos++];
540                         switch (attribute_id){
541                             case 0x02:
542                                 repeat_mode = (avrcp_repeat_mode_t) value;
543                                 break;
544                             case 0x03:
545                                 shuffle_mode = (avrcp_shuffle_mode_t) value;
546                                 break;
547                             default:
548                                 break;
549                         }
550                     }
551                     avrcp_emit_repeat_and_shuffle_mode(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, repeat_mode, shuffle_mode);
552                     break;
553                 }
554                 case AVRCP_PDU_ID_SetPlayerApplicationSettingValue:{
555                     uint8_t event[6];
556                     int offset = 0;
557                     event[offset++] = HCI_EVENT_AVRCP_META;
558                     event[offset++] = sizeof(event) - 2;
559                     event[offset++] = AVRCP_SUBEVENT_PLAYER_APPLICATION_VALUE_RESPONSE;
560                     little_endian_store_16(event, offset, connection->avrcp_cid);
561                     offset += 2;
562                     event[offset++] = ctype;
563                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
564                     break;
565                 }
566                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME:{
567                     uint8_t event[7];
568                     int offset = 0;
569                     event[offset++] = HCI_EVENT_AVRCP_META;
570                     event[offset++] = sizeof(event) - 2;
571                     event[offset++] = AVRCP_SUBEVENT_SET_ABSOLUTE_VOLUME_RESPONSE;
572                     little_endian_store_16(event, offset, connection->avrcp_cid);
573                     offset += 2;
574                     event[offset++] = ctype;
575                     event[offset++] = packet[pos++];
576                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
577                     break;
578                 }
579                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
580                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) packet[pos++];
581                     uint8_t capability_count = packet[pos++];
582                     int i;
583                     switch (capability_id){
584                         case AVRCP_CAPABILITY_ID_COMPANY:
585                             // log_info("Supported companies %d: ", capability_count);
586                             for (i = 0; i < capability_count; i++){
587                                 uint32_t company_id = big_endian_read_24(packet, pos);
588                                 pos += 3;
589                                 log_info("  0x%06" PRIx32 ", ", company_id);
590                             }
591                             break;
592                         case AVRCP_CAPABILITY_ID_EVENT:
593                             // log_info("Supported events %d: ", capability_count);
594                             for (i = 0; i < capability_count; i++){
595                                 uint8_t event_id = packet[pos++];
596                                 log_info("  0x%02x %s", event_id, avrcp_event2str(event_id));
597                             }
598                             break;
599                     }
600                     break;
601                 }
602                 case AVRCP_PDU_ID_GET_PLAY_STATUS:{
603                     uint32_t song_length = big_endian_read_32(packet, pos);
604                     pos += 4;
605                     uint32_t song_position = big_endian_read_32(packet, pos);
606                     pos += 4;
607                     uint8_t play_status = packet[pos];
608                     // log_info("        GET_PLAY_STATUS length 0x%04X, position 0x%04X, status %s", song_length, song_position, avrcp_play_status2str(play_status));
609 
610                     uint8_t event[15];
611                     int offset = 0;
612                     event[offset++] = HCI_EVENT_AVRCP_META;
613                     event[offset++] = sizeof(event) - 2;
614                     event[offset++] = AVRCP_SUBEVENT_PLAY_STATUS;
615                     little_endian_store_16(event, offset, connection->avrcp_cid);
616                     offset += 2;
617                     event[offset++] = ctype;
618                     little_endian_store_32(event, offset, song_length);
619                     offset += 4;
620                     little_endian_store_32(event, offset, song_position);
621                     offset += 4;
622                     event[offset++] = play_status;
623                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
624                     break;
625                 }
626                 case AVRCP_PDU_ID_REGISTER_NOTIFICATION:{
627                     avrcp_notification_event_id_t  event_id = (avrcp_notification_event_id_t) packet[pos++];
628                     uint16_t event_mask = (1 << event_id);
629                     uint16_t reset_event_mask = ~event_mask;
630                     switch (ctype){
631                         case AVRCP_CTYPE_RESPONSE_INTERIM:
632                             // register as enabled
633                             connection->notifications_enabled |= event_mask;
634                             // printf("INTERIM notifications_enabled 0x%2x, notifications_to_register 0x%2x\n", connection->notifications_enabled,  connection->notifications_to_register);
635                             break;
636                         case AVRCP_CTYPE_RESPONSE_CHANGED_STABLE:
637                             // received change, event is considered deregistered
638                             // we are re-enabling it automatically, if it is not
639                             // explicitly disabled
640                             connection->notifications_enabled &= reset_event_mask;
641                             if (! (connection->notifications_to_deregister & event_mask)){
642                                 avrcp_register_notification(connection, event_id);
643                                 // printf("CHANGED_STABLE notifications_enabled 0x%2x, notifications_to_register 0x%2x\n", connection->notifications_enabled,  connection->notifications_to_register);
644                             } else {
645                                 connection->notifications_to_deregister &= reset_event_mask;
646                             }
647                             break;
648                         default:
649                             connection->notifications_to_register &= reset_event_mask;
650                             connection->notifications_enabled &= reset_event_mask;
651                             connection->notifications_to_deregister &= reset_event_mask;
652                             break;
653                     }
654 
655                     switch (event_id){
656                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:{
657                             uint8_t event[7];
658                             int offset = 0;
659                             event[offset++] = HCI_EVENT_AVRCP_META;
660                             event[offset++] = sizeof(event) - 2;
661                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_STATUS_CHANGED;
662                             little_endian_store_16(event, offset, connection->avrcp_cid);
663                             offset += 2;
664                             event[offset++] = ctype;
665                             event[offset++] = packet[pos];
666                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
667                             break;
668                         }
669                         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:{
670                             uint8_t event[6];
671                             int offset = 0;
672                             event[offset++] = HCI_EVENT_AVRCP_META;
673                             event[offset++] = sizeof(event) - 2;
674                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_TRACK_CHANGED;
675                             little_endian_store_16(event, offset, connection->avrcp_cid);
676                             offset += 2;
677                             event[offset++] = ctype;
678                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
679                             break;
680                         }
681                         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:{
682                             uint8_t event[6];
683                             int offset = 0;
684                             event[offset++] = HCI_EVENT_AVRCP_META;
685                             event[offset++] = sizeof(event) - 2;
686                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_NOW_PLAYING_CONTENT_CHANGED;
687                             little_endian_store_16(event, offset, connection->avrcp_cid);
688                             offset += 2;
689                             event[offset++] = ctype;
690                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
691                             break;
692                         }
693                         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:{
694                             uint8_t event[6];
695                             int offset = 0;
696                             event[offset++] = HCI_EVENT_AVRCP_META;
697                             event[offset++] = sizeof(event) - 2;
698                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_AVAILABLE_PLAYERS_CHANGED;
699                             little_endian_store_16(event, offset, connection->avrcp_cid);
700                             offset += 2;
701                             event[offset++] = ctype;
702                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
703                             break;
704                         }
705                         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:{
706                             uint8_t event[7];
707                             int offset = 0;
708                             event[offset++] = HCI_EVENT_AVRCP_META;
709                             event[offset++] = sizeof(event) - 2;
710                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_VOLUME_CHANGED;
711                             little_endian_store_16(event, offset, connection->avrcp_cid);
712                             offset += 2;
713                             event[offset++] = ctype;
714                             event[offset++] = packet[pos++] & 0x7F;
715                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
716                             break;
717                         }
718                         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:{
719                             uint8_t event[7];
720                             int offset = 0;
721                             event[offset++] = HCI_EVENT_AVRCP_META;
722                             event[offset++] = sizeof(event) - 2;
723                             event[offset++] = AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED;
724                             little_endian_store_16(event, offset, connection->avrcp_cid);
725                             offset += 2;
726                             event[offset++] = ctype;
727                             event[offset++] = packet[pos++] & 0x7F;
728                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
729                             break;
730                         }
731 
732                         // case AVRCP_NOTIFICATION_EVENT_PLAYER_APPLICATION_SETTING_CHANGED:{
733                         //     uint8_t num_PlayerApplicationSettingAttributes = packet[pos++];
734                         //     int i;
735                         //     for (i = 0; i < num_PlayerApplicationSettingAttributes; i++){
736                         //         uint8_t PlayerApplicationSetting_AttributeID = packet[pos++];
737                         //         uint8_t PlayerApplicationSettingValueID = packet[pos++];
738                         //     }
739                         //     break;
740                         // }
741                         // case AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED:
742                         //     uint16_t player_id = big_endian_read_16(packet, pos);
743                         //     pos += 2;
744                         //     uint16_t uid_counter = big_endian_read_16(packet, pos);
745                         //     pos += 2;
746                         //     break;
747                         // case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:
748                         //     uint16_t uid_counter = big_endian_read_16(packet, pos);
749                         //     pos += 2;
750                         //     break;
751                         default:
752                             log_info("avrcp: not implemented");
753                             break;
754                     }
755                     if (connection->notifications_to_register != 0){
756                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
757                     }
758                     break;
759                 }
760 
761                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
762                     avrcp_packet_type_t packet_type = operands[4] & 0x03;
763                     switch (packet_type){
764                         case AVRCP_START_PACKET:
765                         case AVRCP_SINGLE_PACKET:
766                             avrcp_parser_reset(connection);
767                             connection->list_size = param_length;
768                             connection->num_attributes = packet[pos++];
769 
770                             // printf("AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES num_attributes %d, total size %d, packet type 0x%02x \n", connection->num_attributes, connection->list_size, operands[4] & 0x03);
771                             avrcp_source_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
772 
773                             if (packet_type == AVRCP_START_PACKET){
774                                 avrcp_controller_request_continue_response(connection);
775                             }
776                             break;
777                         case AVRCP_CONTINUE_PACKET:
778                         case AVRCP_END_PACKET:
779                             connection->num_received_fragments++;
780                             if (connection->num_received_fragments < connection->max_num_fragments){
781                                 avrcp_source_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
782                                 if (packet_type == AVRCP_CONTINUE_PACKET){
783                                     avrcp_controller_request_continue_response(connection);
784                                 }
785                             } else {
786                                 avrcp_controller_request_abort_continuation(connection);
787                                 avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 1);
788                                 avrcp_parser_reset(connection);
789                             }
790                             break;
791                     }
792                 }
793                 default:
794                     break;
795             }
796             break;
797         case AVRCP_CMD_OPCODE_PASS_THROUGH:{
798             // 0x80 | connection->cmd_operands[0]
799             uint8_t operation_id = packet[pos++];
800             switch (connection->state){
801                 case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
802                     if (connection->continuous_fast_forward_cmd){
803                         connection->state = AVCTP_W4_STOP;
804                     } else {
805                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
806                     }
807                     break;
808                 case AVCTP_W2_RECEIVE_RESPONSE:
809                     connection->state = AVCTP_CONNECTION_OPENED;
810                     break;
811                 default:
812                     // check for notifications? move state transition down
813                     // log_info("AVRCP_CMD_OPCODE_PASS_THROUGH state %d\n", connection->state);
814                     break;
815             }
816             if (connection->state == AVCTP_W4_STOP){
817                 avrcp_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_START, connection->avrcp_cid, ctype, operation_id);
818             }
819             if (connection->state == AVCTP_CONNECTION_OPENED) {
820                 // RELEASE response
821                 operation_id = operation_id & 0x7F;
822                 avrcp_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_COMPLETE, connection->avrcp_cid, ctype, operation_id);
823             }
824             if (connection->state == AVCTP_W2_SEND_RELEASE_COMMAND){
825                 // PRESS response
826                 request_pass_through_release_control_cmd(connection);
827             }
828             break;
829         }
830         default:
831             break;
832     }
833 }
834 
835 static void avrcp_controller_handle_can_send_now(avrcp_connection_t * connection){
836     int i;
837     switch (connection->state){
838         case AVCTP_W2_SEND_PRESS_COMMAND:
839             connection->state = AVCTP_W2_RECEIVE_PRESS_RESPONSE;
840             avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
841             break;
842         case AVCTP_W2_SEND_COMMAND:
843         case AVCTP_W2_SEND_RELEASE_COMMAND:
844             connection->state = AVCTP_W2_RECEIVE_RESPONSE;
845             avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
846             break;
847         case AVCTP_CONNECTION_OPENED:
848             if (connection->notifications_to_register != 0){
849                 for (i = 1; i <= AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED; i++){
850                     if (connection->notifications_to_register & (1<<i)){
851                         connection->notifications_to_register &= ~ (1 << i);
852                         avrcp_prepare_notification(connection, (avrcp_notification_event_id_t) i);
853                         connection->state = AVCTP_W2_RECEIVE_RESPONSE;
854                         avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
855                         return;
856                     }
857                 }
858             }
859             return;
860         case AVCTP_W2_SEND_FRAGMENTED_COMMAND:
861             if (connection->cmd_operands_fragmented_pos == 0){
862                  avrcp_send_cmd(connection, AVRCP_START_PACKET);
863                  avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
864             } else {
865                 if (connection->cmd_operands_fragmented_len - connection->cmd_operands_fragmented_pos > avrcp_get_max_payload_size_for_packet_type(AVRCP_CONTINUE_PACKET)){
866                      avrcp_send_cmd(connection, AVRCP_CONTINUE_PACKET);
867                      avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
868                  } else {
869                     connection->state = AVCTP_W2_RECEIVE_RESPONSE;
870                     avrcp_send_cmd(connection, AVRCP_END_PACKET);
871                  }
872             }
873         default:
874             return;
875     }
876 }
877 
878 static void avrcp_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
879     avrcp_connection_t * connection;
880 
881     switch (packet_type) {
882         case L2CAP_DATA_PACKET:
883             connection = get_avrcp_connection_for_l2cap_signaling_cid(channel, &avrcp_controller_context);
884             if (!connection) break;
885             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
886             break;
887         case HCI_EVENT_PACKET:
888             switch (hci_event_packet_get_type(packet)){
889                 case L2CAP_EVENT_CAN_SEND_NOW:
890                     connection = get_avrcp_connection_for_l2cap_signaling_cid(channel, &avrcp_controller_context);
891                     if (!connection) break;
892                     avrcp_controller_handle_can_send_now(connection);
893                     break;
894             default:
895                 avrcp_packet_handler(packet_type, channel, packet, size, &avrcp_controller_context);
896                 break;
897         }
898         default:
899             break;
900     }
901 }
902 
903 void avrcp_controller_init(void){
904     avrcp_controller_context.role = AVRCP_CONTROLLER;
905     avrcp_controller_context.connections = NULL;
906     avrcp_controller_context.packet_handler = avrcp_controller_packet_handler;
907     l2cap_register_service(&avrcp_controller_packet_handler, BLUETOOTH_PROTOCOL_AVCTP, 0xffff, LEVEL_2);
908 }
909 
910 void avrcp_controller_register_packet_handler(btstack_packet_handler_t callback){
911     if (callback == NULL){
912         log_error("avrcp_register_packet_handler called with NULL callback");
913         return;
914     }
915     avrcp_controller_context.avrcp_callback = callback;
916 }
917 
918 uint8_t avrcp_controller_connect(bd_addr_t bd_addr, uint16_t * avrcp_cid){
919     return avrcp_connect(bd_addr, &avrcp_controller_context, avrcp_cid);
920 }
921 
922 uint8_t avrcp_controller_unit_info(uint16_t avrcp_cid){
923     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
924     if (!connection){
925         log_error("avrcp_unit_info: could not find a connection.");
926         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
927     }
928     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
929     connection->state = AVCTP_W2_SEND_COMMAND;
930 
931     connection->transaction_label++;
932     connection->command_opcode = AVRCP_CMD_OPCODE_UNIT_INFO;
933     connection->command_type = AVRCP_CTYPE_STATUS;
934     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
935     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
936     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
937     connection->cmd_operands_length = 5;
938     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
939     return ERROR_CODE_SUCCESS;
940 }
941 
942 uint8_t avrcp_controller_subunit_info(uint16_t avrcp_cid){
943     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
944     if (!connection){
945         log_error("avrcp_unit_info: could not find a connection.");
946         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
947     }
948     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
949     connection->state = AVCTP_W2_SEND_COMMAND;
950 
951     connection->transaction_label++;
952     connection->command_opcode = AVRCP_CMD_OPCODE_SUBUNIT_INFO;
953     connection->command_type = AVRCP_CTYPE_STATUS;
954     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
955     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
956     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
957     connection->cmd_operands[0] = 7; // page: 0, extention_code: 7
958     connection->cmd_operands_length = 5;
959     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
960     return ERROR_CODE_SUCCESS;
961 }
962 
963 static uint8_t avrcp_controller_get_capabilities(uint16_t avrcp_cid, uint8_t capability_id){
964     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
965     if (!connection){
966         log_error("avrcp_get_capabilities: could not find a connection.");
967         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
968     }
969     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
970     connection->state = AVCTP_W2_SEND_COMMAND;
971 
972     connection->transaction_label++;
973     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
974     connection->command_type = AVRCP_CTYPE_STATUS;
975     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
976     connection->subunit_id = AVRCP_SUBUNIT_ID;
977     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
978     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_CAPABILITIES; // PDU ID
979     connection->cmd_operands[4] = 0;
980     big_endian_store_16(connection->cmd_operands, 5, 1); // parameter length
981     connection->cmd_operands[7] = capability_id;                  // capability ID
982     connection->cmd_operands_length = 8;
983     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
984     return ERROR_CODE_SUCCESS;
985 }
986 
987 uint8_t avrcp_controller_get_supported_company_ids(uint16_t avrcp_cid){
988     return avrcp_controller_get_capabilities(avrcp_cid, AVRCP_CAPABILITY_ID_COMPANY);
989 }
990 
991 uint8_t avrcp_controller_get_supported_events(uint16_t avrcp_cid){
992     return avrcp_controller_get_capabilities(avrcp_cid, AVRCP_CAPABILITY_ID_EVENT);
993 }
994 
995 
996 uint8_t avrcp_controller_play(uint16_t avrcp_cid){
997     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
998 }
999 
1000 uint8_t avrcp_controller_stop(uint16_t avrcp_cid){
1001     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1002 }
1003 
1004 uint8_t avrcp_controller_pause(uint16_t avrcp_cid){
1005     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1006 }
1007 
1008 uint8_t avrcp_controller_forward(uint16_t avrcp_cid){
1009     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1010 }
1011 
1012 uint8_t avrcp_controller_backward(uint16_t avrcp_cid){
1013     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1014 }
1015 
1016 uint8_t avrcp_controller_volume_up(uint16_t avrcp_cid){
1017     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1018 }
1019 
1020 uint8_t avrcp_controller_volume_down(uint16_t avrcp_cid){
1021     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1022 }
1023 
1024 uint8_t avrcp_controller_mute(uint16_t avrcp_cid){
1025     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1026 }
1027 
1028 uint8_t avrcp_controller_skip(uint16_t avrcp_cid){
1029     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_SKIP, 0);
1030 }
1031 
1032 uint8_t avrcp_controller_fast_forward(uint16_t avrcp_cid){
1033     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1034 }
1035 
1036 uint8_t avrcp_controller_rewind(uint16_t avrcp_cid){
1037     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1038 }
1039 
1040 
1041 /* start cmds */
1042 
1043 uint8_t avrcp_controller_release_press_and_hold_cmd(uint16_t avrcp_cid){
1044     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1045     if (!connection){
1046         log_error("avrcp_stop_play: could not find a connection.");
1047         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1048     }
1049     if (connection->state != AVCTP_W4_STOP) return ERROR_CODE_COMMAND_DISALLOWED;
1050     return request_pass_through_release_control_cmd(connection);
1051 }
1052 
1053 uint8_t avrcp_controller_press_and_hold_play(uint16_t avrcp_cid){
1054     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1055 }
1056 uint8_t avrcp_controller_press_and_hold_stop(uint16_t avrcp_cid){
1057     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1058 }
1059 uint8_t avrcp_controller_press_and_hold_pause(uint16_t avrcp_cid){
1060     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1061 }
1062 uint8_t avrcp_controller_press_and_hold_forward(uint16_t avrcp_cid){
1063     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1064 }
1065 uint8_t avrcp_controller_press_and_hold_backward(uint16_t avrcp_cid){
1066     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1067 }
1068 uint8_t avrcp_controller_press_and_hold_fast_forward(uint16_t avrcp_cid){
1069     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1070 }
1071 uint8_t avrcp_controller_press_and_hold_rewind(uint16_t avrcp_cid){
1072     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1073 }
1074 uint8_t avrcp_controller_press_and_hold_volume_up(uint16_t avrcp_cid){
1075     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1076 }
1077 uint8_t avrcp_controller_press_and_hold_volume_down(uint16_t avrcp_cid){
1078     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1079 }
1080 uint8_t avrcp_controller_press_and_hold_mute(uint16_t avrcp_cid){
1081     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1082 }
1083 
1084 
1085 /* stop continuous cmds */
1086 
1087 uint8_t avrcp_controller_get_play_status(uint16_t avrcp_cid){
1088     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1089     if (!connection){
1090         log_error("avrcp_get_play_status: could not find a connection.");
1091         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1092     }
1093     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1094     connection->state = AVCTP_W2_SEND_COMMAND;
1095     connection->transaction_label++;
1096     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1097     connection->command_type = AVRCP_CTYPE_STATUS;
1098     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1099     connection->subunit_id = AVRCP_SUBUNIT_ID;
1100     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1101     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_PLAY_STATUS;
1102     connection->cmd_operands[4] = 0;                     // reserved(upper 6) | packet_type -> 0
1103     big_endian_store_16(connection->cmd_operands, 5, 0); // parameter length
1104     connection->cmd_operands_length = 7;
1105     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1106     return ERROR_CODE_SUCCESS;
1107 }
1108 
1109 uint8_t avrcp_controller_enable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1110     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1111     if (!connection){
1112         log_error("avrcp_get_play_status: could not find a connection.");
1113         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1114     }
1115     avrcp_register_notification(connection, event_id);
1116     return ERROR_CODE_SUCCESS;
1117 }
1118 
1119 uint8_t avrcp_controller_disable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1120     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1121     if (!connection){
1122         log_error("avrcp_get_play_status: could not find a connection.");
1123         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1124     }
1125     connection->notifications_to_deregister |= (1 << event_id);
1126     return ERROR_CODE_SUCCESS;
1127 }
1128 
1129 uint8_t avrcp_controller_set_addressed_player(uint16_t avrcp_cid, uint16_t addressed_player_id){
1130     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1131     if (!connection){
1132         log_error("avrcp_get_capabilities: could not find a connection.");
1133         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1134     }
1135     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1136     connection->state = AVCTP_W2_SEND_COMMAND;
1137 
1138     connection->transaction_label++;
1139     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1140     connection->command_type = AVRCP_CTYPE_CONTROL;
1141     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1142     connection->subunit_id = AVRCP_SUBUNIT_ID;
1143     int pos = 0;
1144     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1145     pos += 3;
1146     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ADDRESSED_PLAYER; // PDU ID
1147     connection->cmd_operands[pos++] = 0;
1148 
1149     // Parameter Length
1150     big_endian_store_16(connection->cmd_operands, pos, 2);
1151     pos += 2;
1152 
1153     big_endian_store_16(connection->cmd_operands, pos, addressed_player_id);
1154     pos += 2;
1155 
1156     connection->cmd_operands_length = pos;
1157     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1158     return ERROR_CODE_SUCCESS;
1159 }
1160 
1161 uint8_t avrcp_controller_get_now_playing_info(uint16_t avrcp_cid){
1162     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1163     if (!connection){
1164         log_error("avrcp_get_capabilities: could not find a connection.");
1165         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1166     }
1167     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1168     connection->state = AVCTP_W2_SEND_COMMAND;
1169 
1170     connection->transaction_label++;
1171     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1172     connection->command_type = AVRCP_CTYPE_STATUS;
1173     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1174     connection->subunit_id = AVRCP_SUBUNIT_ID;
1175     int pos = 0;
1176     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1177     pos += 3;
1178     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES; // PDU ID
1179     connection->cmd_operands[pos++] = 0;
1180 
1181     // Parameter Length
1182     big_endian_store_16(connection->cmd_operands, pos, 9);
1183     pos += 2;
1184 
1185     // write 8 bytes value
1186     memset(connection->cmd_operands + pos, 0, 8); // identifier: PLAYING
1187     pos += 8;
1188 
1189     connection->cmd_operands[pos++] = 0; // attribute count, if 0 get all attributes
1190     // every attribute is 4 bytes long
1191 
1192     connection->cmd_operands_length = pos;
1193     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1194     return ERROR_CODE_SUCCESS;
1195 }
1196 
1197 uint8_t avrcp_controller_set_absolute_volume(uint16_t avrcp_cid, uint8_t volume){
1198      avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1199     if (!connection){
1200         log_error("avrcp_get_capabilities: could not find a connection.");
1201         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1202     }
1203     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1204     connection->state = AVCTP_W2_SEND_COMMAND;
1205 
1206     connection->transaction_label++;
1207     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1208     connection->command_type = AVRCP_CTYPE_CONTROL;
1209     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1210     connection->subunit_id = AVRCP_SUBUNIT_ID;
1211     int pos = 0;
1212     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1213     pos += 3;
1214     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME; // PDU ID
1215     connection->cmd_operands[pos++] = 0;
1216 
1217     // Parameter Length
1218     big_endian_store_16(connection->cmd_operands, pos, 1);
1219     pos += 2;
1220     connection->cmd_operands[pos++] = volume;
1221 
1222     connection->cmd_operands_length = pos;
1223     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1224     return ERROR_CODE_SUCCESS;
1225 }
1226 
1227 uint8_t avrcp_controller_query_shuffle_and_repeat_modes(uint16_t avrcp_cid){
1228     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1229     if (!connection){
1230         log_error("avrcp_get_capabilities: could not find a connection.");
1231         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1232     }
1233     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1234     connection->state = AVCTP_W2_SEND_COMMAND;
1235 
1236     connection->transaction_label++;
1237     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1238     connection->command_type = AVRCP_CTYPE_STATUS;
1239     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1240     connection->subunit_id = AVRCP_SUBUNIT_ID;
1241     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1242     connection->cmd_operands[3] = AVRCP_PDU_ID_GetCurrentPlayerApplicationSettingValue; // PDU ID
1243     connection->cmd_operands[4] = 0;
1244     big_endian_store_16(connection->cmd_operands, 5, 5); // parameter length
1245     connection->cmd_operands[7] = 4;                     // NumPlayerApplicationSettingAttributeID
1246     // PlayerApplicationSettingAttributeID1 AVRCP Spec, Appendix F, 133
1247     connection->cmd_operands[8]  = 0x01;    // equalizer  (1-OFF, 2-ON)
1248     connection->cmd_operands[9]  = 0x02;    // repeat     (1-off, 2-single track, 3-all tracks, 4-group repeat)
1249     connection->cmd_operands[10] = 0x03;    // shuffle    (1-off, 2-all tracks, 3-group shuffle)
1250     connection->cmd_operands[11] = 0x04;    // scan       (1-off, 2-all tracks, 3-group scan)
1251     connection->cmd_operands_length = 12;
1252     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1253     return ERROR_CODE_SUCCESS;
1254 }
1255 
1256 static uint8_t avrcp_controller_set_current_player_application_setting_value(uint16_t avrcp_cid, uint8_t attr_id, uint8_t attr_value){
1257     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1258     if (!connection){
1259         log_error("avrcp_get_capabilities: could not find a connection.");
1260         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1261     }
1262     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1263     connection->state = AVCTP_W2_SEND_COMMAND;
1264 
1265     connection->transaction_label++;
1266     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1267     connection->command_type = AVRCP_CTYPE_CONTROL;
1268     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1269     connection->subunit_id = AVRCP_SUBUNIT_ID;
1270     int pos = 0;
1271     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1272     pos += 3;
1273     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SetPlayerApplicationSettingValue; // PDU ID
1274     connection->cmd_operands[pos++] = 0;
1275     // Parameter Length
1276     big_endian_store_16(connection->cmd_operands, pos, 3);
1277     pos += 2;
1278     connection->cmd_operands[pos++] = 2;
1279     connection->cmd_operands_length = pos;
1280     connection->cmd_operands[pos++]  = attr_id;
1281     connection->cmd_operands[pos++]  = attr_value;
1282     connection->cmd_operands_length = pos;
1283     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1284     return ERROR_CODE_SUCCESS;
1285 }
1286 
1287 uint8_t avrcp_controller_set_shuffle_mode(uint16_t avrcp_cid, avrcp_shuffle_mode_t mode){
1288     if (mode < AVRCP_SHUFFLE_MODE_OFF || mode > AVRCP_SHUFFLE_MODE_GROUP) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1289     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x03, mode);
1290 }
1291 
1292 uint8_t avrcp_controller_set_repeat_mode(uint16_t avrcp_cid, avrcp_repeat_mode_t mode){
1293     if (mode < AVRCP_REPEAT_MODE_OFF || mode > AVRCP_REPEAT_MODE_GROUP) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1294     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x02, mode);
1295 }
1296 
1297 uint8_t avrcp_controller_disconnect(uint16_t avrcp_cid){
1298     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1299     if (!connection){
1300         log_error("avrcp_get_capabilities: could not find a connection.");
1301         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1302     }
1303     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1304     if (connection->browsing_connection){
1305         if (connection->browsing_connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1306         l2cap_disconnect(connection->browsing_connection->l2cap_browsing_cid, 0);
1307     }
1308     l2cap_disconnect(connection->l2cap_signaling_cid, 0);
1309     return ERROR_CODE_SUCCESS;
1310 }
1311 
1312 uint8_t avrcp_controller_play_item_for_scope(uint16_t avrcp_cid, uint8_t * uid, uint16_t uid_counter, avrcp_browsing_scope_t scope){
1313     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1314     if (!connection){
1315         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1316         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1317     }
1318     if (connection->state != AVCTP_CONNECTION_OPENED){
1319         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1320         return ERROR_CODE_COMMAND_DISALLOWED;
1321     }
1322     connection->state = AVCTP_W2_SEND_COMMAND;
1323 
1324     connection->transaction_label++;
1325     connection->command_type = AVRCP_CTYPE_CONTROL;
1326     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1327     connection->subunit_id = AVRCP_SUBUNIT_ID;
1328     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1329     int pos = 0;
1330     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1331     pos += 3;
1332     connection->cmd_operands[pos++] = AVRCP_PDU_ID_PLAY_ITEM; // PDU ID
1333     // reserved
1334     connection->cmd_operands[pos++] = 0;
1335     // Parameter Length
1336     big_endian_store_16(connection->cmd_operands, pos, 11);
1337     pos += 2;
1338     connection->cmd_operands[pos++]  = scope;
1339     memset(&connection->cmd_operands[pos], 0, 8);
1340     if (uid){
1341         memcpy(&connection->cmd_operands[pos], uid, 8);
1342     }
1343     pos += 8;
1344     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1345     pos += 2;
1346     connection->cmd_operands_length = pos;
1347 
1348     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1349     return ERROR_CODE_SUCCESS;
1350 }
1351 
1352 uint8_t avrcp_controller_add_item_from_scope_to_now_playing_list(uint16_t avrcp_cid, uint8_t * uid, uint16_t uid_counter, avrcp_browsing_scope_t scope){
1353     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1354     if (!connection){
1355         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1356         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1357     }
1358     if (connection->state != AVCTP_CONNECTION_OPENED){
1359         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1360         return ERROR_CODE_COMMAND_DISALLOWED;
1361     }
1362     connection->state = AVCTP_W2_SEND_COMMAND;
1363 
1364     connection->transaction_label++;
1365     connection->command_type = AVRCP_CTYPE_CONTROL;
1366     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1367     connection->subunit_id = AVRCP_SUBUNIT_ID;
1368     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1369     int pos = 0;
1370     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1371     pos += 3;
1372     connection->cmd_operands[pos++] = AVRCP_PDU_ID_ADD_TO_NOW_PLAYING; // PDU ID
1373     // reserved
1374     connection->cmd_operands[pos++] = 0;
1375     // Parameter Length
1376     big_endian_store_16(connection->cmd_operands, pos, 11);
1377     pos += 2;
1378     connection->cmd_operands[pos++]  = scope;
1379     memset(&connection->cmd_operands[pos], 0, 8);
1380     if (uid){
1381         memcpy(&connection->cmd_operands[pos], uid, 8);
1382     }
1383     pos += 8;
1384     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1385     pos += 2;
1386     connection->cmd_operands_length = pos;
1387 
1388     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1389     return ERROR_CODE_SUCCESS;
1390 }
1391 
1392 uint8_t avrcp_controller_set_max_num_fragments(uint16_t avrcp_cid, uint8_t max_num_fragments){
1393     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1394     if (!connection){
1395         log_error("avrcp_controller_play_item: could not find a connection.");
1396         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1397     }
1398     connection->max_num_fragments = max_num_fragments;
1399     return ERROR_CODE_SUCCESS;
1400 }
1401 
1402 uint8_t avrcp_controller_send_custom_command(uint16_t avrcp_cid, avrcp_command_type_t command_type, avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id, avrcp_command_opcode_t command_opcode, const uint8_t * command_buffer, uint16_t command_len){
1403     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1404     if (!connection){
1405         log_error("avrcp_controller_play_item: could not find a connection.");
1406         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1407     }
1408 
1409     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1410     connection->state = AVCTP_W2_SEND_FRAGMENTED_COMMAND;
1411 
1412     connection->transaction_label++;
1413     connection->command_opcode = command_opcode;
1414     connection->command_type = command_type;
1415     connection->subunit_type = subunit_type;
1416     connection->subunit_id = subunit_id;
1417     connection->cmd_operands_fragmented_buffer = command_buffer;
1418     connection->cmd_operands_fragmented_pos = 0;
1419     connection->cmd_operands_fragmented_len = command_len;
1420 
1421     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1422     return ERROR_CODE_SUCCESS;
1423 }
1424