xref: /btstack/example/a2dp_source_demo.c (revision 762141afa59a4094329f828b2e84ec60cf9c372c)
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 BLUEKITCHEN
24  * GMBH 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__ "a2dp_source_demo.c"
39 
40 /*
41  * a2dp_source_demo.c
42  */
43 
44 // *****************************************************************************
45 /* EXAMPLE_START(a2dp_source_demo): A2DP Source - Stream Audio and Control Volume
46  *
47  * @text This A2DP Source example demonstrates how to send an audio data stream
48  * to a remote A2DP Sink device and how to switch between two audio data sources.
49  * In addition, the AVRCP Target is used to answer queries on currently played media,
50  * as well as to handle remote playback control, i.e. play, stop, repeat, etc. If HAVE_BTSTACK_STDIN
51  * is set, press SPACE on the console to show the available AVDTP and AVRCP commands.
52  *
53  * @text To test with a remote device, e.g. a Bluetooth speaker,
54  * set the device_addr_string to the Bluetooth address of your
55  * remote device in the code, and use the UI to connect and start playback.
56  *
57  * @text For more info on BTstack audio, see our blog post
58  * [A2DP Sink and Source on STM32 F4 Discovery Board](http://bluekitchen-gmbh.com/a2dp-sink-and-source-on-stm32-f4-discovery-board/).
59  *
60  */
61 // *****************************************************************************
62 
63 
64 #include <stdint.h>
65 #include <stdio.h>
66 #include <inttypes.h>
67 #include <string.h>
68 
69 #include "btstack.h"
70 #include "hxcmod.h"
71 #include "mods/mod.h"
72 
73 // logarithmic volume reduction, samples are divided by 2^x
74 // #define VOLUME_REDUCTION 3
75 
76 //#define AVRCP_BROWSING_ENABLED
77 
78 #define NUM_CHANNELS                2
79 #define BYTES_PER_AUDIO_SAMPLE      (2*NUM_CHANNELS)
80 #define AUDIO_TIMEOUT_MS            10
81 #define TABLE_SIZE_441HZ            100
82 
83 #define SBC_STORAGE_SIZE 1030
84 
85 typedef enum {
86     STREAM_SINE = 0,
87     STREAM_MOD,
88     STREAM_PTS_TEST
89 } stream_data_source_t;
90 
91 typedef struct {
92     uint16_t a2dp_cid;
93     uint8_t  local_seid;
94     uint8_t  remote_seid;
95     uint8_t  stream_opened;
96     uint16_t avrcp_cid;
97 
98     uint32_t time_audio_data_sent; // ms
99     uint32_t acc_num_missed_samples;
100     uint32_t samples_ready;
101     btstack_timer_source_t audio_timer;
102     uint8_t  streaming;
103     int      max_media_payload_size;
104     uint32_t rtp_timestamp;
105 
106     uint8_t  sbc_storage[SBC_STORAGE_SIZE];
107     uint16_t sbc_storage_count;
108     uint8_t  sbc_ready_to_send;
109 
110     uint8_t volume;
111 } a2dp_media_sending_context_t;
112 
113 static  uint8_t media_sbc_codec_capabilities[] = {
114     (AVDTP_SBC_44100 << 4) | AVDTP_SBC_STEREO,
115     0xFF,//(AVDTP_SBC_BLOCK_LENGTH_16 << 4) | (AVDTP_SBC_SUBBANDS_8 << 2) | AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS,
116     2, 53
117 };
118 
119 // input signal: pre-computed int16 sine wave, 44100 Hz at 441 Hz
120 static const int16_t sine_int16_44100[] = {
121      0,    2057,    4107,    6140,    8149,   10126,   12062,   13952,   15786,   17557,
122  19260,   20886,   22431,   23886,   25247,   26509,   27666,   28714,   29648,   30466,
123  31163,   31738,   32187,   32509,   32702,   32767,   32702,   32509,   32187,   31738,
124  31163,   30466,   29648,   28714,   27666,   26509,   25247,   23886,   22431,   20886,
125  19260,   17557,   15786,   13952,   12062,   10126,    8149,    6140,    4107,    2057,
126      0,   -2057,   -4107,   -6140,   -8149,  -10126,  -12062,  -13952,  -15786,  -17557,
127 -19260,  -20886,  -22431,  -23886,  -25247,  -26509,  -27666,  -28714,  -29648,  -30466,
128 -31163,  -31738,  -32187,  -32509,  -32702,  -32767,  -32702,  -32509,  -32187,  -31738,
129 -31163,  -30466,  -29648,  -28714,  -27666,  -26509,  -25247,  -23886,  -22431,  -20886,
130 -19260,  -17557,  -15786,  -13952,  -12062,  -10126,   -8149,   -6140,   -4107,   -2057,
131 };
132 
133 static const int num_samples_sine_int16_44100 = sizeof(sine_int16_44100) / 2;
134 
135 // input signal: pre-computed int16 sine wave, 48000 Hz at 441 Hz
136 static const int16_t sine_int16_48000[] = {
137      0,    1905,    3804,    5690,    7557,    9398,   11207,   12978,   14706,   16383,
138  18006,   19567,   21062,   22486,   23834,   25101,   26283,   27376,   28377,   29282,
139  30087,   30791,   31390,   31884,   32269,   32545,   32712,   32767,   32712,   32545,
140  32269,   31884,   31390,   30791,   30087,   29282,   28377,   27376,   26283,   25101,
141  23834,   22486,   21062,   19567,   18006,   16383,   14706,   12978,   11207,    9398,
142   7557,    5690,    3804,    1905,       0,   -1905,   -3804,   -5690,   -7557,   -9398,
143 -11207,  -12978,  -14706,  -16384,  -18006,  -19567,  -21062,  -22486,  -23834,  -25101,
144 -26283,  -27376,  -28377,  -29282,  -30087,  -30791,  -31390,  -31884,  -32269,  -32545,
145 -32712,  -32767,  -32712,  -32545,  -32269,  -31884,  -31390,  -30791,  -30087,  -29282,
146 -28377,  -27376,  -26283,  -25101,  -23834,  -22486,  -21062,  -19567,  -18006,  -16384,
147 -14706,  -12978,  -11207,   -9398,   -7557,   -5690,   -3804,   -1905,  };
148 
149 static const int num_samples_sine_int16_48000 = sizeof(sine_int16_48000) / 2;
150 
151 static const int A2DP_SOURCE_DEMO_INQUIRY_DURATION_1280MS = 12;
152 
153 typedef struct {
154     int reconfigure;
155 
156     int num_channels;
157     int sampling_frequency;
158     int block_length;
159     int subbands;
160     int min_bitpool_value;
161     int max_bitpool_value;
162     btstack_sbc_channel_mode_t      channel_mode;
163     btstack_sbc_allocation_method_t allocation_method;
164 } media_codec_configuration_sbc_t;
165 
166 static btstack_packet_callback_registration_t hci_event_callback_registration;
167 
168 // Minijambox:
169 static const char * device_addr_string = "00:21:3C:AC:F7:38";
170 
171 static bd_addr_t device_addr;
172 static bool scan_active;
173 
174 static uint8_t sdp_a2dp_source_service_buffer[150];
175 static uint8_t sdp_avrcp_target_service_buffer[200];
176 static uint8_t sdp_avrcp_controller_service_buffer[200];
177 static uint8_t device_id_sdp_service_buffer[100];
178 
179 static media_codec_configuration_sbc_t sbc_configuration;
180 static btstack_sbc_encoder_state_t sbc_encoder_state;
181 
182 static uint8_t media_sbc_codec_configuration[4];
183 static a2dp_media_sending_context_t media_tracker;
184 
185 static stream_data_source_t data_source;
186 
187 static int sine_phase;
188 static int current_sample_rate = 44100;
189 static int new_sample_rate = 44100;
190 
191 static int hxcmod_initialized;
192 static modcontext mod_context;
193 static tracker_buffer_state trkbuf;
194 
195 /* AVRCP Target context START */
196 
197 typedef struct {
198     uint8_t track_id[8];
199     uint32_t song_length_ms;
200     avrcp_playback_status_t status;
201     uint32_t song_position_ms; // 0xFFFFFFFF if not supported
202 } avrcp_play_status_info_t;
203 
204 // python -c "print('a'*512)"
205 static const char title[] = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
206 
207 avrcp_track_t tracks[] = {
208     {{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01}, 1, "Sine", "Generated", "A2DP Source Demo", "monotone", 12345},
209     {{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02}, 2, "Nao-deceased", "Decease", "A2DP Source Demo", "vivid", 12345},
210     {{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03}, 3, (char *)title, "Decease", "A2DP Source Demo", "vivid", 12345},
211 };
212 int current_track_index;
213 avrcp_play_status_info_t play_info;
214 
215 /* AVRCP Target context END */
216 
217 /* @section Main Application Setup
218  *
219  * @text The Listing MainConfiguration shows how to setup AD2P Source and AVRCP services.
220  * Besides calling init() method for each service, you'll also need to register several packet handlers:
221  * - hci_packet_handler - handles legacy pairing, here by using fixed '0000' pin code.
222  * - a2dp_source_packet_handler - handles events on stream connection status (established, released), the media codec configuration, and, the commands on stream itself (open, pause, stopp).
223  * - avrcp_packet_handler - receives connect/disconnect event.
224  * - avrcp_controller_packet_handler - receives answers for sent AVRCP commands.
225  * - avrcp_target_packet_handler - receives AVRCP commands, and registered notifications.
226  * - stdin_process - used to trigger AVRCP commands to the A2DP Source device, such are get now playing info, start, stop, volume control. Requires HAVE_BTSTACK_STDIN.
227  *
228  * @text To announce A2DP Source and AVRCP services, you need to create corresponding
229  * SDP records and register them with the SDP service.
230  */
231 
232 /* LISTING_START(MainConfiguration): Setup Audio Source and AVRCP Target services */
233 static void hci_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
234 static void a2dp_source_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t * event, uint16_t event_size);
235 static void avrcp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
236 static void avrcp_target_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
237 static void avrcp_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
238 #ifdef HAVE_BTSTACK_STDIN
239 static void stdin_process(char cmd);
240 #endif
241 
242 static void a2dp_demo_hexcmod_configure_sample_rate(int sample_rate);
243 
244 static int a2dp_source_and_avrcp_services_init(void){
245 
246     // Request role change on reconnecting headset to always use them in slave mode
247     hci_set_master_slave_policy(0);
248     // enabled EIR
249     hci_set_inquiry_mode(INQUIRY_MODE_RSSI_AND_EIR);
250 
251     l2cap_init();
252 
253 #ifdef ENABLE_BLE
254     // Initialize LE Security Manager. Needed for cross-transport key derivation
255     sm_init();
256 #endif
257 
258     // Initialize  A2DP Source
259     a2dp_source_init();
260     a2dp_source_register_packet_handler(&a2dp_source_packet_handler);
261 
262     // Create stream endpoint
263     avdtp_stream_endpoint_t * local_stream_endpoint = a2dp_source_create_stream_endpoint(AVDTP_AUDIO, AVDTP_CODEC_SBC, media_sbc_codec_capabilities, sizeof(media_sbc_codec_capabilities), media_sbc_codec_configuration, sizeof(media_sbc_codec_configuration));
264     if (!local_stream_endpoint){
265         printf("A2DP Source: not enough memory to create local stream endpoint\n");
266         return 1;
267     }
268 
269     // Store stream enpoint's SEP ID, as it is used by A2DP API to indentify the stream endpoint
270     media_tracker.local_seid = avdtp_local_seid(local_stream_endpoint);
271     avdtp_source_register_delay_reporting_category(media_tracker.local_seid);
272 
273     // Initialize AVRCP Service
274     avrcp_init();
275     avrcp_register_packet_handler(&avrcp_packet_handler);
276     // Initialize AVRCP Target
277     avrcp_target_init();
278     avrcp_target_register_packet_handler(&avrcp_target_packet_handler);
279 
280     // Initialize AVRCP Controller
281     avrcp_controller_init();
282     avrcp_controller_register_packet_handler(&avrcp_controller_packet_handler);
283 
284     // Initialize SDP,
285     sdp_init();
286 
287     // Create A2DP Source service record and register it with SDP
288     memset(sdp_a2dp_source_service_buffer, 0, sizeof(sdp_a2dp_source_service_buffer));
289     a2dp_source_create_sdp_record(sdp_a2dp_source_service_buffer, sdp_create_service_record_handle(), AVDTP_SOURCE_FEATURE_MASK_PLAYER, NULL, NULL);
290     btstack_assert(de_get_len( sdp_a2dp_source_service_buffer) <= sizeof(sdp_a2dp_source_service_buffer));
291     sdp_register_service(sdp_a2dp_source_service_buffer);
292 
293     // Create AVRCP Target service record and register it with SDP. We receive Category 1 commands from the headphone, e.g. play/pause
294     memset(sdp_avrcp_target_service_buffer, 0, sizeof(sdp_avrcp_target_service_buffer));
295     uint16_t supported_features = AVRCP_FEATURE_MASK_CATEGORY_PLAYER_OR_RECORDER;
296 #ifdef AVRCP_BROWSING_ENABLED
297     supported_features |= AVRCP_FEATURE_MASK_BROWSING;
298 #endif
299     avrcp_target_create_sdp_record(sdp_avrcp_target_service_buffer, sdp_create_service_record_handle(), supported_features, NULL, NULL);
300     btstack_assert(de_get_len( sdp_avrcp_target_service_buffer) <= sizeof(sdp_avrcp_target_service_buffer));
301     sdp_register_service(sdp_avrcp_target_service_buffer);
302 
303     // Create AVRCP Controller service record and register it with SDP. We send Category 2 commands to the headphone, e.g. volume up/down
304     memset(sdp_avrcp_controller_service_buffer, 0, sizeof(sdp_avrcp_controller_service_buffer));
305     uint16_t controller_supported_features = AVRCP_FEATURE_MASK_CATEGORY_MONITOR_OR_AMPLIFIER;
306     avrcp_controller_create_sdp_record(sdp_avrcp_controller_service_buffer, sdp_create_service_record_handle(), controller_supported_features, NULL, NULL);
307     btstack_assert(de_get_len( sdp_avrcp_controller_service_buffer) <= sizeof(sdp_avrcp_controller_service_buffer));
308     sdp_register_service(sdp_avrcp_controller_service_buffer);
309 
310     // Register Device ID (PnP) service SDP record
311     memset(device_id_sdp_service_buffer, 0, sizeof(device_id_sdp_service_buffer));
312     device_id_create_sdp_record(device_id_sdp_service_buffer, sdp_create_service_record_handle(), DEVICE_ID_VENDOR_ID_SOURCE_BLUETOOTH, BLUETOOTH_COMPANY_ID_BLUEKITCHEN_GMBH, 1, 1);
313     btstack_assert(de_get_len( device_id_sdp_service_buffer) <= sizeof(device_id_sdp_service_buffer));
314     sdp_register_service(device_id_sdp_service_buffer);
315 
316     // Set local name with a template Bluetooth address, that will be automatically
317     // replaced with a actual address once it is available, i.e. when BTstack boots
318     // up and starts talking to a Bluetooth module.
319     gap_set_local_name("A2DP Source 00:00:00:00:00:00");
320     gap_discoverable_control(1);
321     gap_set_class_of_device(0x200408);
322 
323     // Register for HCI events.
324     hci_event_callback_registration.callback = &hci_packet_handler;
325     hci_add_event_handler(&hci_event_callback_registration);
326 
327     a2dp_demo_hexcmod_configure_sample_rate(current_sample_rate);
328     data_source = STREAM_MOD;
329 
330     // Parse human readable Bluetooth address.
331     sscanf_bd_addr(device_addr_string, device_addr);
332 
333 #ifdef HAVE_BTSTACK_STDIN
334     btstack_stdin_setup(stdin_process);
335 #endif
336     return 0;
337 }
338 /* LISTING_END */
339 
340 static void a2dp_demo_hexcmod_configure_sample_rate(int sample_rate){
341     if (!hxcmod_initialized){
342         hxcmod_initialized = hxcmod_init(&mod_context);
343         if (!hxcmod_initialized) {
344             printf("could not initialize hxcmod\n");
345             return;
346         }
347     }
348     current_sample_rate = sample_rate;
349     media_tracker.sbc_storage_count = 0;
350     media_tracker.samples_ready = 0;
351     hxcmod_unload(&mod_context);
352     hxcmod_setcfg(&mod_context, current_sample_rate, 16, 1, 1, 1);
353     hxcmod_load(&mod_context, (void *) &mod_data, mod_len);
354 }
355 
356 static void a2dp_demo_send_media_packet(void){
357     int num_bytes_in_frame = btstack_sbc_encoder_sbc_buffer_length();
358     int bytes_in_storage = media_tracker.sbc_storage_count;
359     uint8_t num_sbc_frames = bytes_in_storage / num_bytes_in_frame;
360     // Prepend SBC Header
361     media_tracker.sbc_storage[0] = num_sbc_frames;  // (fragmentation << 7) | (starting_packet << 6) | (last_packet << 5) | num_frames;
362     a2dp_source_stream_send_media_payload_rtp(media_tracker.a2dp_cid, media_tracker.local_seid, 0,
363                                                media_tracker.rtp_timestamp,
364                                                media_tracker.sbc_storage, bytes_in_storage + 1);
365 
366     // update rtp_timestamp
367     unsigned int num_audio_samples_per_sbc_buffer = btstack_sbc_encoder_num_audio_frames();
368     media_tracker.rtp_timestamp += num_sbc_frames * num_audio_samples_per_sbc_buffer;
369 
370     media_tracker.sbc_storage_count = 0;
371     media_tracker.sbc_ready_to_send = 0;
372 }
373 
374 static void produce_sine_audio(int16_t * pcm_buffer, int num_samples_to_write){
375     int count;
376     for (count = 0; count < num_samples_to_write ; count++){
377         switch (current_sample_rate){
378             case 44100:
379                 pcm_buffer[count * 2]     = sine_int16_44100[sine_phase];
380                 pcm_buffer[count * 2 + 1] = sine_int16_44100[sine_phase];
381                 sine_phase++;
382                 if (sine_phase >= num_samples_sine_int16_44100){
383                     sine_phase -= num_samples_sine_int16_44100;
384                 }
385                 break;
386             case 48000:
387                 pcm_buffer[count * 2]     = sine_int16_48000[sine_phase];
388                 pcm_buffer[count * 2 + 1] = sine_int16_48000[sine_phase];
389                 sine_phase++;
390                 if (sine_phase >= num_samples_sine_int16_48000){
391                     sine_phase -= num_samples_sine_int16_48000;
392                 }
393                 break;
394             default:
395                 break;
396         }
397     }
398 }
399 
400 static void produce_mod_audio(int16_t * pcm_buffer, int num_samples_to_write){
401     hxcmod_fillbuffer(&mod_context, (unsigned short *) &pcm_buffer[0], num_samples_to_write, &trkbuf);
402 }
403 
404 static void produce_audio(int16_t * pcm_buffer, int num_samples){
405     switch (data_source){
406         case STREAM_SINE:
407             produce_sine_audio(pcm_buffer, num_samples);
408             break;
409         case STREAM_MOD:
410             produce_mod_audio(pcm_buffer, num_samples);
411             break;
412         default:
413             break;
414     }
415 #ifdef VOLUME_REDUCTION
416     int i;
417     for (i=0;i<num_samples*2;i++){
418         if (pcm_buffer[i] > 0){
419             pcm_buffer[i] =     pcm_buffer[i]  >> VOLUME_REDUCTION;
420         } else {
421             pcm_buffer[i] = -((-pcm_buffer[i]) >> VOLUME_REDUCTION);
422         }
423     }
424 #endif
425 }
426 
427 static int a2dp_demo_fill_sbc_audio_buffer(a2dp_media_sending_context_t * context){
428     // perform sbc encoding
429     int total_num_bytes_read = 0;
430     unsigned int num_audio_samples_per_sbc_buffer = btstack_sbc_encoder_num_audio_frames();
431     while (context->samples_ready >= num_audio_samples_per_sbc_buffer
432         && (context->max_media_payload_size - context->sbc_storage_count) >= btstack_sbc_encoder_sbc_buffer_length()){
433 
434         int16_t pcm_frame[256*NUM_CHANNELS];
435 
436         produce_audio(pcm_frame, num_audio_samples_per_sbc_buffer);
437         btstack_sbc_encoder_process_data(pcm_frame);
438 
439         uint16_t sbc_frame_size = btstack_sbc_encoder_sbc_buffer_length();
440         uint8_t * sbc_frame = btstack_sbc_encoder_sbc_buffer();
441 
442         total_num_bytes_read += num_audio_samples_per_sbc_buffer;
443         // first byte in sbc storage contains sbc media header
444         memcpy(&context->sbc_storage[1 + context->sbc_storage_count], sbc_frame, sbc_frame_size);
445         context->sbc_storage_count += sbc_frame_size;
446         context->samples_ready -= num_audio_samples_per_sbc_buffer;
447     }
448     return total_num_bytes_read;
449 }
450 
451 static void a2dp_demo_audio_timeout_handler(btstack_timer_source_t * timer){
452     a2dp_media_sending_context_t * context = (a2dp_media_sending_context_t *) btstack_run_loop_get_timer_context(timer);
453     btstack_run_loop_set_timer(&context->audio_timer, AUDIO_TIMEOUT_MS);
454     btstack_run_loop_add_timer(&context->audio_timer);
455     uint32_t now = btstack_run_loop_get_time_ms();
456 
457     uint32_t update_period_ms = AUDIO_TIMEOUT_MS;
458     if (context->time_audio_data_sent > 0){
459         update_period_ms = now - context->time_audio_data_sent;
460     }
461 
462     uint32_t num_samples = (update_period_ms * current_sample_rate) / 1000;
463     context->acc_num_missed_samples += (update_period_ms * current_sample_rate) % 1000;
464 
465     while (context->acc_num_missed_samples >= 1000){
466         num_samples++;
467         context->acc_num_missed_samples -= 1000;
468     }
469     context->time_audio_data_sent = now;
470     context->samples_ready += num_samples;
471 
472     if (context->sbc_ready_to_send) return;
473 
474     a2dp_demo_fill_sbc_audio_buffer(context);
475 
476     if ((context->sbc_storage_count + btstack_sbc_encoder_sbc_buffer_length()) > context->max_media_payload_size){
477         // schedule sending
478         context->sbc_ready_to_send = 1;
479         a2dp_source_stream_endpoint_request_can_send_now(context->a2dp_cid, context->local_seid);
480     }
481 }
482 
483 static void a2dp_demo_timer_start(a2dp_media_sending_context_t * context){
484     context->max_media_payload_size = btstack_min(a2dp_max_media_payload_size(context->a2dp_cid, context->local_seid), SBC_STORAGE_SIZE);
485     context->sbc_storage_count = 0;
486     context->sbc_ready_to_send = 0;
487     context->streaming = 1;
488     btstack_run_loop_remove_timer(&context->audio_timer);
489     btstack_run_loop_set_timer_handler(&context->audio_timer, a2dp_demo_audio_timeout_handler);
490     btstack_run_loop_set_timer_context(&context->audio_timer, context);
491     btstack_run_loop_set_timer(&context->audio_timer, AUDIO_TIMEOUT_MS);
492     btstack_run_loop_add_timer(&context->audio_timer);
493 }
494 
495 static void a2dp_demo_timer_stop(a2dp_media_sending_context_t * context){
496     context->time_audio_data_sent = 0;
497     context->acc_num_missed_samples = 0;
498     context->samples_ready = 0;
499     context->streaming = 1;
500     context->sbc_storage_count = 0;
501     context->sbc_ready_to_send = 0;
502     btstack_run_loop_remove_timer(&context->audio_timer);
503 }
504 
505 static void dump_sbc_configuration(media_codec_configuration_sbc_t * configuration){
506     printf("Received media codec configuration:\n");
507     printf("    - num_channels: %d\n", configuration->num_channels);
508     printf("    - sampling_frequency: %d\n", configuration->sampling_frequency);
509     printf("    - channel_mode: %d\n", configuration->channel_mode);
510     printf("    - block_length: %d\n", configuration->block_length);
511     printf("    - subbands: %d\n", configuration->subbands);
512     printf("    - allocation_method: %d\n", configuration->allocation_method);
513     printf("    - bitpool_value [%d, %d] \n", configuration->min_bitpool_value, configuration->max_bitpool_value);
514 }
515 
516 static void a2dp_source_demo_start_scanning(void){
517     printf("Start scanning...\n");
518     gap_inquiry_start(A2DP_SOURCE_DEMO_INQUIRY_DURATION_1280MS);
519     scan_active = true;
520 }
521 
522 static void hci_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
523     UNUSED(channel);
524     UNUSED(size);
525     if (packet_type != HCI_EVENT_PACKET) return;
526     uint8_t status;
527     UNUSED(status);
528 
529     bd_addr_t address;
530     uint32_t cod;
531 
532     // Service Class: Rendering | Audio, Major Device Class: Audio
533     const uint32_t bluetooth_speaker_cod = 0x200000 | 0x040000 | 0x000400;
534 
535     switch (hci_event_packet_get_type(packet)){
536 #ifndef HAVE_BTSTACK_STDIN
537         case  BTSTACK_EVENT_STATE:
538             if (btstack_event_state_get_state(packet) != HCI_STATE_WORKING) return;
539             a2dp_source_demo_start_scanning();
540             break;
541 #endif
542         case HCI_EVENT_PIN_CODE_REQUEST:
543             printf("Pin code request - using '0000'\n");
544             hci_event_pin_code_request_get_bd_addr(packet, address);
545             gap_pin_code_response(address, "0000");
546             break;
547         case GAP_EVENT_INQUIRY_RESULT:
548             gap_event_inquiry_result_get_bd_addr(packet, address);
549             // print info
550             printf("Device found: %s ",  bd_addr_to_str(address));
551             cod = gap_event_inquiry_result_get_class_of_device(packet);
552             printf("with COD: %06" PRIx32, cod);
553             if (gap_event_inquiry_result_get_rssi_available(packet)){
554                 printf(", rssi %d dBm", (int8_t) gap_event_inquiry_result_get_rssi(packet));
555             }
556             if (gap_event_inquiry_result_get_name_available(packet)){
557                 char name_buffer[240];
558                 int name_len = gap_event_inquiry_result_get_name_len(packet);
559                 memcpy(name_buffer, gap_event_inquiry_result_get_name(packet), name_len);
560                 name_buffer[name_len] = 0;
561                 printf(", name '%s'", name_buffer);
562             }
563             printf("\n");
564             if ((cod & bluetooth_speaker_cod) == bluetooth_speaker_cod){
565                 memcpy(device_addr, address, 6);
566                 printf("Bluetooth speaker detected, trying to connect to %s...\n", bd_addr_to_str(device_addr));
567                 scan_active = false;
568                 gap_inquiry_stop();
569                 a2dp_source_establish_stream(device_addr, &media_tracker.a2dp_cid);
570             }
571             break;
572         case GAP_EVENT_INQUIRY_COMPLETE:
573             if (scan_active){
574                 printf("No Bluetooth speakers found, scanning again...\n");
575                 gap_inquiry_start(A2DP_SOURCE_DEMO_INQUIRY_DURATION_1280MS);
576             }
577             break;
578         default:
579             break;
580     }
581 }
582 
583 static void a2dp_source_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
584     UNUSED(channel);
585     UNUSED(size);
586     uint8_t status;
587     uint8_t local_seid;
588     bd_addr_t address;
589     uint16_t cid;
590 
591     avdtp_channel_mode_t channel_mode;
592     uint8_t allocation_method;
593 
594     if (packet_type != HCI_EVENT_PACKET) return;
595     if (hci_event_packet_get_type(packet) != HCI_EVENT_A2DP_META) return;
596 
597     switch (hci_event_a2dp_meta_get_subevent_code(packet)){
598         case A2DP_SUBEVENT_SIGNALING_CONNECTION_ESTABLISHED:
599             a2dp_subevent_signaling_connection_established_get_bd_addr(packet, address);
600             cid = a2dp_subevent_signaling_connection_established_get_a2dp_cid(packet);
601             status = a2dp_subevent_signaling_connection_established_get_status(packet);
602 
603             if (status != ERROR_CODE_SUCCESS){
604                 printf("A2DP Source: Connection failed, status 0x%02x, cid 0x%02x, a2dp_cid 0x%02x \n", status, cid, media_tracker.a2dp_cid);
605                 media_tracker.a2dp_cid = 0;
606                 break;
607             }
608             media_tracker.a2dp_cid = cid;
609             media_tracker.volume = 32;
610 
611             printf("A2DP Source: Connected to address %s, a2dp cid 0x%02x, local seid 0x%02x.\n", bd_addr_to_str(address), media_tracker.a2dp_cid, media_tracker.local_seid);
612             break;
613 
614          case A2DP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CONFIGURATION:{
615             cid  = avdtp_subevent_signaling_media_codec_sbc_configuration_get_avdtp_cid(packet);
616             if (cid != media_tracker.a2dp_cid) return;
617 
618             media_tracker.remote_seid = a2dp_subevent_signaling_media_codec_sbc_configuration_get_remote_seid(packet);
619 
620             sbc_configuration.reconfigure = a2dp_subevent_signaling_media_codec_sbc_configuration_get_reconfigure(packet);
621             sbc_configuration.num_channels = a2dp_subevent_signaling_media_codec_sbc_configuration_get_num_channels(packet);
622             sbc_configuration.sampling_frequency = a2dp_subevent_signaling_media_codec_sbc_configuration_get_sampling_frequency(packet);
623             sbc_configuration.block_length = a2dp_subevent_signaling_media_codec_sbc_configuration_get_block_length(packet);
624             sbc_configuration.subbands = a2dp_subevent_signaling_media_codec_sbc_configuration_get_subbands(packet);
625             sbc_configuration.min_bitpool_value = a2dp_subevent_signaling_media_codec_sbc_configuration_get_min_bitpool_value(packet);
626             sbc_configuration.max_bitpool_value = a2dp_subevent_signaling_media_codec_sbc_configuration_get_max_bitpool_value(packet);
627 
628             channel_mode = (avdtp_channel_mode_t) a2dp_subevent_signaling_media_codec_sbc_configuration_get_channel_mode(packet);
629             allocation_method = a2dp_subevent_signaling_media_codec_sbc_configuration_get_allocation_method(packet);
630 
631             printf("A2DP Source: Received SBC codec configuration, sampling frequency %u, a2dp_cid 0x%02x, local seid 0x%02x, remote seid 0x%02x.\n",
632                 sbc_configuration.sampling_frequency, cid,
633                    a2dp_subevent_signaling_media_codec_sbc_configuration_get_local_seid(packet),
634                    a2dp_subevent_signaling_media_codec_sbc_configuration_get_remote_seid(packet));
635 
636             // Adapt Bluetooth spec definition to SBC Encoder expected input
637             sbc_configuration.allocation_method = (btstack_sbc_allocation_method_t)(allocation_method - 1);
638             switch (channel_mode){
639                 case AVDTP_CHANNEL_MODE_JOINT_STEREO:
640                     sbc_configuration.channel_mode = SBC_CHANNEL_MODE_JOINT_STEREO;
641                     break;
642                 case AVDTP_CHANNEL_MODE_STEREO:
643                     sbc_configuration.channel_mode = SBC_CHANNEL_MODE_STEREO;
644                     break;
645                 case AVDTP_CHANNEL_MODE_DUAL_CHANNEL:
646                     sbc_configuration.channel_mode = SBC_CHANNEL_MODE_DUAL_CHANNEL;
647                     break;
648                 case AVDTP_CHANNEL_MODE_MONO:
649                     sbc_configuration.channel_mode = SBC_CHANNEL_MODE_MONO;
650                     break;
651                 default:
652                     btstack_assert(false);
653                     break;
654             }
655             dump_sbc_configuration(&sbc_configuration);
656 
657             btstack_sbc_encoder_init(&sbc_encoder_state, SBC_MODE_STANDARD,
658                 sbc_configuration.block_length, sbc_configuration.subbands,
659                 sbc_configuration.allocation_method, sbc_configuration.sampling_frequency,
660                 sbc_configuration.max_bitpool_value,
661                 sbc_configuration.channel_mode);
662             break;
663         }
664 
665         case A2DP_SUBEVENT_SIGNALING_DELAY_REPORTING_CAPABILITY:
666             printf("A2DP Source: remote supports delay report, remote seid %d\n",
667                 avdtp_subevent_signaling_delay_reporting_capability_get_remote_seid(packet));
668             break;
669         case A2DP_SUBEVENT_SIGNALING_CAPABILITIES_DONE:
670             printf("A2DP Source: All capabilities reported, remote seid %d\n",
671                 avdtp_subevent_signaling_capabilities_done_get_remote_seid(packet));
672             break;
673 
674         case A2DP_SUBEVENT_SIGNALING_DELAY_REPORT:
675             printf("A2DP Source: Received delay report of %d.%0d ms, local seid %d\n",
676                 avdtp_subevent_signaling_delay_report_get_delay_100us(packet)/10, avdtp_subevent_signaling_delay_report_get_delay_100us(packet)%10,
677                 avdtp_subevent_signaling_delay_report_get_local_seid(packet));
678             break;
679 
680         case A2DP_SUBEVENT_STREAM_ESTABLISHED:
681             a2dp_subevent_stream_established_get_bd_addr(packet, address);
682             status = a2dp_subevent_stream_established_get_status(packet);
683             if (status != ERROR_CODE_SUCCESS){
684                 printf("A2DP Source: Stream failed, status 0x%02x.\n", status);
685                 break;
686             }
687 
688             local_seid = a2dp_subevent_stream_established_get_local_seid(packet);
689             cid = a2dp_subevent_stream_established_get_a2dp_cid(packet);
690 
691             printf("A2DP Source: Stream established a2dp_cid 0x%02x, local_seid 0x%02x, remote_seid 0x%02x\n", cid, local_seid, a2dp_subevent_stream_established_get_remote_seid(packet));
692 
693             a2dp_demo_hexcmod_configure_sample_rate(current_sample_rate);
694             media_tracker.stream_opened = 1;
695             status = a2dp_source_start_stream(media_tracker.a2dp_cid, media_tracker.local_seid);
696             break;
697 
698         case A2DP_SUBEVENT_STREAM_RECONFIGURED:
699             status = a2dp_subevent_stream_reconfigured_get_status(packet);
700             local_seid = a2dp_subevent_stream_reconfigured_get_local_seid(packet);
701             cid = a2dp_subevent_stream_reconfigured_get_a2dp_cid(packet);
702 
703             if (status != ERROR_CODE_SUCCESS){
704                 printf("A2DP Source: Stream reconfiguration failed, status 0x%02x\n", status);
705                 break;
706             }
707 
708             printf("A2DP Source: Stream reconfigured a2dp_cid 0x%02x, local_seid 0x%02x\n", cid, local_seid);
709             a2dp_demo_hexcmod_configure_sample_rate(new_sample_rate);
710             status = a2dp_source_start_stream(media_tracker.a2dp_cid, media_tracker.local_seid);
711             break;
712 
713         case A2DP_SUBEVENT_STREAM_STARTED:
714             local_seid = a2dp_subevent_stream_started_get_local_seid(packet);
715             cid = a2dp_subevent_stream_started_get_a2dp_cid(packet);
716 
717             play_info.status = AVRCP_PLAYBACK_STATUS_PLAYING;
718             if (media_tracker.avrcp_cid){
719                 avrcp_target_set_now_playing_info(media_tracker.avrcp_cid, &tracks[data_source], sizeof(tracks)/sizeof(avrcp_track_t));
720                 avrcp_target_set_playback_status(media_tracker.avrcp_cid, AVRCP_PLAYBACK_STATUS_PLAYING);
721             }
722             a2dp_demo_timer_start(&media_tracker);
723             printf("A2DP Source: Stream started, a2dp_cid 0x%02x, local_seid 0x%02x\n", cid, local_seid);
724             break;
725 
726         case A2DP_SUBEVENT_STREAMING_CAN_SEND_MEDIA_PACKET_NOW:
727             local_seid = a2dp_subevent_streaming_can_send_media_packet_now_get_local_seid(packet);
728             cid = a2dp_subevent_signaling_media_codec_sbc_configuration_get_a2dp_cid(packet);
729             a2dp_demo_send_media_packet();
730             break;
731 
732         case A2DP_SUBEVENT_STREAM_SUSPENDED:
733             local_seid = a2dp_subevent_stream_suspended_get_local_seid(packet);
734             cid = a2dp_subevent_stream_suspended_get_a2dp_cid(packet);
735 
736             play_info.status = AVRCP_PLAYBACK_STATUS_PAUSED;
737             if (media_tracker.avrcp_cid){
738                 avrcp_target_set_playback_status(media_tracker.avrcp_cid, AVRCP_PLAYBACK_STATUS_PAUSED);
739             }
740             printf("A2DP Source: Stream paused, a2dp_cid 0x%02x, local_seid 0x%02x\n", cid, local_seid);
741 
742             a2dp_demo_timer_stop(&media_tracker);
743             break;
744 
745         case A2DP_SUBEVENT_STREAM_RELEASED:
746             play_info.status = AVRCP_PLAYBACK_STATUS_STOPPED;
747             cid = a2dp_subevent_stream_released_get_a2dp_cid(packet);
748             local_seid = a2dp_subevent_stream_released_get_local_seid(packet);
749 
750             printf("A2DP Source: Stream released, a2dp_cid 0x%02x, local_seid 0x%02x\n", cid, local_seid);
751 
752             if (cid == media_tracker.a2dp_cid) {
753                 media_tracker.stream_opened = 0;
754                 printf("A2DP Source: Stream released.\n");
755             }
756             if (media_tracker.avrcp_cid){
757                 avrcp_target_set_now_playing_info(media_tracker.avrcp_cid, NULL, sizeof(tracks)/sizeof(avrcp_track_t));
758                 avrcp_target_set_playback_status(media_tracker.avrcp_cid, AVRCP_PLAYBACK_STATUS_STOPPED);
759             }
760             a2dp_demo_timer_stop(&media_tracker);
761             break;
762         case A2DP_SUBEVENT_SIGNALING_CONNECTION_RELEASED:
763             cid = a2dp_subevent_signaling_connection_released_get_a2dp_cid(packet);
764             if (cid == media_tracker.a2dp_cid) {
765                 media_tracker.avrcp_cid = 0;
766                 media_tracker.a2dp_cid = 0;
767                 printf("A2DP Source: Signaling released.\n\n");
768             }
769             break;
770         default:
771             break;
772     }
773 }
774 
775 static void avrcp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
776     UNUSED(channel);
777     UNUSED(size);
778     bd_addr_t event_addr;
779     uint16_t local_cid;
780     uint8_t  status = ERROR_CODE_SUCCESS;
781 
782     if (packet_type != HCI_EVENT_PACKET) return;
783     if (hci_event_packet_get_type(packet) != HCI_EVENT_AVRCP_META) return;
784 
785     switch (packet[2]){
786         case AVRCP_SUBEVENT_CONNECTION_ESTABLISHED:
787             local_cid = avrcp_subevent_connection_established_get_avrcp_cid(packet);
788             status = avrcp_subevent_connection_established_get_status(packet);
789             if (status != ERROR_CODE_SUCCESS){
790                 printf("AVRCP: Connection failed, local cid 0x%02x, status 0x%02x\n", local_cid, status);
791                 return;
792             }
793             media_tracker.avrcp_cid = local_cid;
794             avrcp_subevent_connection_established_get_bd_addr(packet, event_addr);
795 
796             printf("AVRCP: Channel to %s successfully opened, avrcp_cid 0x%02x\n", bd_addr_to_str(event_addr), media_tracker.avrcp_cid);
797 
798             avrcp_target_support_event(media_tracker.avrcp_cid, AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED);
799             avrcp_target_support_event(media_tracker.avrcp_cid, AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED);
800             avrcp_target_support_event(media_tracker.avrcp_cid, AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED);
801             avrcp_target_set_now_playing_info(media_tracker.avrcp_cid, NULL, sizeof(tracks)/sizeof(avrcp_track_t));
802 
803             printf("Enable Volume Change notification\n");
804             avrcp_controller_enable_notification(media_tracker.avrcp_cid, AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED);
805             printf("Enable Battery Status Change notification\n");
806             avrcp_controller_enable_notification(media_tracker.avrcp_cid, AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED);
807             return;
808 
809         case AVRCP_SUBEVENT_CONNECTION_RELEASED:
810             printf("AVRCP Target: Disconnected, avrcp_cid 0x%02x\n", avrcp_subevent_connection_released_get_avrcp_cid(packet));
811             media_tracker.avrcp_cid = 0;
812             return;
813         default:
814             break;
815     }
816 
817     if (status != ERROR_CODE_SUCCESS){
818         printf("Responding to event 0x%02x failed, status 0x%02x\n", packet[2], status);
819     }
820 }
821 
822 static void avrcp_target_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
823     UNUSED(channel);
824     UNUSED(size);
825     uint8_t  status = ERROR_CODE_SUCCESS;
826 
827     if (packet_type != HCI_EVENT_PACKET) return;
828     if (hci_event_packet_get_type(packet) != HCI_EVENT_AVRCP_META) return;
829 
830     bool button_pressed;
831     char const * button_state;
832     avrcp_operation_id_t operation_id;
833 
834     switch (packet[2]){
835         case AVRCP_SUBEVENT_PLAY_STATUS_QUERY:
836             status = avrcp_target_play_status(media_tracker.avrcp_cid, play_info.song_length_ms, play_info.song_position_ms, play_info.status);
837             break;
838         // case AVRCP_SUBEVENT_NOW_PLAYING_INFO_QUERY:
839         //     status = avrcp_target_now_playing_info(avrcp_cid);
840         //     break;
841         case AVRCP_SUBEVENT_OPERATION:
842             operation_id = avrcp_subevent_operation_get_operation_id(packet);
843             button_pressed = avrcp_subevent_operation_get_button_pressed(packet) > 0;
844             button_state = button_pressed ? "PRESS" : "RELEASE";
845 
846             printf("AVRCP Target: operation %s (%s)\n", avrcp_operation2str(operation_id), button_state);
847 
848             if (!button_pressed){
849                 break;
850             }
851             switch (operation_id) {
852                 case AVRCP_OPERATION_ID_PLAY:
853                     status = a2dp_source_start_stream(media_tracker.a2dp_cid, media_tracker.local_seid);
854                     break;
855                 case AVRCP_OPERATION_ID_PAUSE:
856                     status = a2dp_source_pause_stream(media_tracker.a2dp_cid, media_tracker.local_seid);
857                     break;
858                 case AVRCP_OPERATION_ID_STOP:
859                     status = a2dp_source_disconnect(media_tracker.a2dp_cid);
860                     break;
861                 default:
862                     break;
863             }
864             break;
865         default:
866             break;
867     }
868 
869     if (status != ERROR_CODE_SUCCESS){
870         printf("Responding to event 0x%02x failed, status 0x%02x\n", packet[2], status);
871     }
872 }
873 
874 static void avrcp_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
875     UNUSED(channel);
876     UNUSED(size);
877 
878     if (packet_type != HCI_EVENT_PACKET) return;
879     if (hci_event_packet_get_type(packet) != HCI_EVENT_AVRCP_META) return;
880     if (!media_tracker.avrcp_cid) return;
881 
882     switch (packet[2]){
883         case AVRCP_SUBEVENT_NOTIFICATION_VOLUME_CHANGED:
884             printf("AVRCP Controller: Notification Absolute Volume %d %%\n", avrcp_subevent_notification_volume_changed_get_absolute_volume(packet) * 100 / 127);
885             break;
886         case AVRCP_SUBEVENT_NOTIFICATION_EVENT_BATT_STATUS_CHANGED:
887             // see avrcp_battery_status_t
888             printf("AVRCP Controller: Notification Battery Status 0x%02x\n", avrcp_subevent_notification_event_batt_status_changed_get_battery_status(packet));
889             break;
890         case AVRCP_SUBEVENT_NOTIFICATION_STATE:
891             printf("AVRCP Controller: Notification %s - %s\n",
892                 avrcp_event2str(avrcp_subevent_notification_state_get_event_id(packet)),
893                 avrcp_subevent_notification_state_get_enabled(packet) != 0 ? "enabled" : "disabled");
894             break;
895         default:
896             break;
897     }
898 }
899 
900 #ifdef HAVE_BTSTACK_STDIN
901 static void show_usage(void){
902     bd_addr_t      iut_address;
903     gap_local_bd_addr(iut_address);
904     printf("\n--- Bluetooth  A2DP Source/AVRCP Demo %s ---\n", bd_addr_to_str(iut_address));
905     printf("a      - Scan for Bluetooth speaker and connect\n");
906     printf("b      - A2DP Source create connection to addr %s\n", device_addr_string);
907     printf("B      - A2DP Source disconnect\n");
908     printf("c      - AVRCP create connection to addr %s\n", device_addr_string);
909     printf("C      - AVRCP disconnect\n");
910     printf("D      - delete all link keys\n");
911 
912     printf("x      - start streaming sine\n");
913     if (hxcmod_initialized){
914         printf("z      - start streaming '%s'\n", mod_name);
915     }
916     printf("p      - pause streaming\n");
917     printf("w      - reconfigure stream for 44100 Hz\n");
918     printf("e      - reconfigure stream for 48000 Hz\n");
919     printf("t      - volume up\n");
920     printf("T      - volume down\n");
921     printf("v      - volume up (via set absolute volume)\n");
922     printf("V      - volume down (via set absolute volume)\n");
923 
924     printf("---\n");
925 }
926 
927 static void stdin_process(char cmd){
928     uint8_t status = ERROR_CODE_SUCCESS;
929     switch (cmd){
930         case 'a':
931             a2dp_source_demo_start_scanning();
932             break;
933         case 'b':
934             status = a2dp_source_establish_stream(device_addr, &media_tracker.a2dp_cid);
935             printf("%c - Create A2DP Source connection to addr %s, cid 0x%02x.\n", cmd, bd_addr_to_str(device_addr), media_tracker.a2dp_cid);
936             break;
937         case 'B':
938             printf("%c - A2DP Source Disconnect from cid 0x%2x\n", cmd, media_tracker.a2dp_cid);
939             status = a2dp_source_disconnect(media_tracker.a2dp_cid);
940             break;
941         case 'c':
942             printf("%c - Create AVRCP connection to addr %s.\n", cmd, bd_addr_to_str(device_addr));
943             status = avrcp_connect(device_addr, &media_tracker.avrcp_cid);
944             break;
945         case 'C':
946             printf("%c - AVRCP disconnect\n", cmd);
947             status = avrcp_disconnect(media_tracker.avrcp_cid);
948             break;
949         case 'D':
950             printf("Deleting all link keys\n");
951             gap_delete_all_link_keys();
952             break;
953         case '\n':
954         case '\r':
955             break;
956 
957         case 't':
958             printf(" - volume up\n");
959             status = avrcp_controller_volume_up(media_tracker.avrcp_cid);
960             break;
961         case 'T':
962             printf(" - volume down\n");
963             status = avrcp_controller_volume_down(media_tracker.avrcp_cid);
964             break;
965 
966         case 'v':
967             if (media_tracker.volume > 117){
968                 media_tracker.volume = 127;
969             } else {
970                 media_tracker.volume += 10;
971             }
972             printf(" - volume up (via set absolute volume) %d%% (%d)\n",  media_tracker.volume * 100 / 127,  media_tracker.volume);
973             status = avrcp_controller_set_absolute_volume(media_tracker.avrcp_cid, media_tracker.volume);
974             break;
975         case 'V':
976             if (media_tracker.volume < 10){
977                 media_tracker.volume = 0;
978             } else {
979                 media_tracker.volume -= 10;
980             }
981             printf(" - volume down (via set absolute volume) %d%% (%d)\n",  media_tracker.volume * 100 / 127,  media_tracker.volume);
982             status = avrcp_controller_set_absolute_volume(media_tracker.avrcp_cid, media_tracker.volume);
983             break;
984 
985         case 'x':
986             if (media_tracker.avrcp_cid){
987                 avrcp_target_set_now_playing_info(media_tracker.avrcp_cid, &tracks[data_source], sizeof(tracks)/sizeof(avrcp_track_t));
988             }
989             printf("%c - Play sine.\n", cmd);
990             data_source = STREAM_SINE;
991             if (!media_tracker.stream_opened) break;
992             status = a2dp_source_start_stream(media_tracker.a2dp_cid, media_tracker.local_seid);
993             break;
994         case 'z':
995             if (media_tracker.avrcp_cid){
996                 avrcp_target_set_now_playing_info(media_tracker.avrcp_cid, &tracks[data_source], sizeof(tracks)/sizeof(avrcp_track_t));
997             }
998             printf("%c - Play mod.\n", cmd);
999             data_source = STREAM_MOD;
1000             if (!media_tracker.stream_opened) break;
1001             status = a2dp_source_start_stream(media_tracker.a2dp_cid, media_tracker.local_seid);
1002             break;
1003 
1004         case 'p':
1005             if (!media_tracker.stream_opened) break;
1006             printf("%c - Pause stream.\n", cmd);
1007             status = a2dp_source_pause_stream(media_tracker.a2dp_cid, media_tracker.local_seid);
1008             break;
1009 
1010         case 'w':
1011             if (!media_tracker.stream_opened) break;
1012             if (play_info.status == AVRCP_PLAYBACK_STATUS_PLAYING){
1013                 printf("Stream cannot be reconfigured while playing, please pause stream first\n");
1014                 break;
1015             }
1016             new_sample_rate = 44100;
1017             if (current_sample_rate == new_sample_rate){
1018                 printf("%c - Stream already configured for %d Hz.\n", cmd, new_sample_rate);
1019             } else {
1020                 printf("%c - Reconfigure for %d Hz.\n", cmd, new_sample_rate);
1021                 status = a2dp_source_reconfigure_stream_sampling_frequency(media_tracker.a2dp_cid, new_sample_rate);
1022             }
1023             break;
1024 
1025         case 'e':
1026             if (!media_tracker.stream_opened) break;
1027             if (play_info.status == AVRCP_PLAYBACK_STATUS_PLAYING){
1028                 printf("Stream cannot be reconfigured while playing, please pause stream first\n");
1029                 break;
1030             }
1031             new_sample_rate = 48000;
1032             if (current_sample_rate == new_sample_rate){
1033                 printf("%c - Stream already configured for %d Hz.\n", cmd, new_sample_rate);
1034             } else {
1035                 printf("%c - Reconfigure for %d Hz.\n", cmd, new_sample_rate);
1036                 status = a2dp_source_reconfigure_stream_sampling_frequency(media_tracker.a2dp_cid, new_sample_rate);
1037             }
1038             break;
1039 
1040         default:
1041             show_usage();
1042             return;
1043     }
1044     if (status != ERROR_CODE_SUCCESS){
1045         printf("Could not perform command \'%c\', status 0x%02x\n", cmd, status);
1046     }
1047 }
1048 #endif
1049 
1050 
1051 int btstack_main(int argc, const char * argv[]);
1052 int btstack_main(int argc, const char * argv[]){
1053     (void)argc;
1054     (void)argv;
1055 
1056     int err = a2dp_source_and_avrcp_services_init();
1057     if (err) return err;
1058     // turn on!
1059     hci_power_control(HCI_POWER_ON);
1060     return 0;
1061 }
1062 /* EXAMPLE_END */
1063