xref: /btstack/example/le_audio_demo_util_sink.c (revision 2d612fc882f1a1c9e9df22e29afe1d54e97f55bc)
1 /*
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37 
38 #define BTSTACK_FILE__ "le_audio_demo_util_sink.c"
39 
40 #include <stdio.h>
41 
42 #include "le_audio_demo_util_sink.h"
43 
44 #include "btstack_bool.h"
45 #include "btstack_config.h"
46 #include <btstack_debug.h>
47 #include <printf.h>
48 
49 #include "hci.h"
50 #include "btstack_audio.h"
51 #include "btstack_lc3_google.h"
52 #include "btstack_lc3plus_fraunhofer.h"
53 
54 #include "btstack_sample_rate_compensation.h"
55 #include "btstack_resample.h"
56 
57 #include "hxcmod.h"
58 #include "mods/mod.h"
59 
60 #ifdef HAVE_POSIX_FILE_IO
61 #include "wav_util.h"
62 #include "btstack_ring_buffer.h"
63 
64 #endif
65 
66 //#define DEBUG_PLC
67 #ifdef DEBUG_PLC
68 #define printf_plc(...) { \
69     printf(__VA_ARGS__);  \
70     log_info(__VA_ARGS__);\
71 }
72 #else
73 #define printf_plc(...)  (void)(0);
74 #endif
75 
76 #define MAX_CHANNELS 2
77 #define MAX_SAMPLES_PER_FRAME 480
78 #define MAX_LC3_FRAME_BYTES   155
79 
80 // playback
81 #define MAX_NUM_LC3_FRAMES   15
82 #define MAX_BYTES_PER_SAMPLE 4
83 #define PLAYBACK_BUFFER_SIZE (MAX_NUM_LC3_FRAMES * MAX_SAMPLES_PER_FRAME * MAX_CHANNELS * MAX_BYTES_PER_SAMPLE)
84 #define PLAYBACK_START_MS (MAX_NUM_LC3_FRAMES * 20 / 3)
85 
86 #define ANSI_COLOR_RED     "\x1b[31m"
87 #define ANSI_COLOR_GREEN   "\x1b[32m"
88 #define ANSI_COLOR_YELLOW  "\x1b[33m"
89 #define ANSI_COLOR_BLUE    "\x1b[34m"
90 #define ANSI_COLOR_MAGENTA "\x1b[35m"
91 #define ANSI_COLOR_CYAN    "\x1b[36m"
92 #define ANSI_COLOR_RESET   "\x1b[0m"
93 
94 // SINK
95 
96 static enum {
97     LE_AUDIO_SINK_IDLE,
98     LE_AUDIO_SINK_INIT,
99     LE_AUDIO_SINK_CONFIGURED,
100 } le_audio_demo_util_sink_state = LE_AUDIO_SINK_IDLE;
101 
102 static const char * le_audio_demo_sink_filename_wav;
103 static btstack_sample_rate_compensation_t sample_rate_compensation;
104 static uint32_t le_audio_demo_sink_received_samples;
105 static btstack_resample_t resample_instance;
106 static bool sink_receive_streaming;
107 
108 static int16_t pcm_resample[MAX_CHANNELS * MAX_SAMPLES_PER_FRAME * 2];
109 
110 
111 static btstack_lc3_frame_duration_t le_audio_demo_sink_frame_duration;
112 static hci_iso_type_t               le_audio_demo_sink_type;
113 
114 static uint32_t le_audio_demo_sink_sampling_frequency_hz;
115 static uint16_t le_audio_demo_sink_num_samples_per_frame;
116 static uint8_t  le_audio_demo_sink_num_streams;
117 static uint8_t  le_audio_demo_sink_num_channels_per_stream;
118 static uint8_t  le_audio_demo_sink_num_channels;
119 static uint16_t le_audio_demo_sink_octets_per_frame;
120 static uint16_t le_audio_demo_sink_iso_interval_1250us;
121 static uint8_t  le_audio_demo_sink_flush_timeout;
122 static uint8_t  le_audio_demo_sink_pre_transmission_offset;
123 
124 // playback
125 static uint16_t              playback_start_threshold_bytes;
126 static bool                  playback_active;
127 static uint8_t               playback_buffer_storage[PLAYBACK_BUFFER_SIZE];
128 static btstack_ring_buffer_t playback_buffer;
129 
130 // PLC
131 static bool     stream_last_packet_received[MAX_CHANNELS];
132 static uint16_t stream_last_packet_sequence[MAX_CHANNELS];
133 static uint16_t group_last_packet_sequence;
134 static bool     group_last_packet_received;
135 static uint16_t plc_timeout_initial_ms;
136 static uint16_t plc_timeout_subsequent_ms;
137 
138 static uint32_t le_audio_demo_sink_lc3_frames;
139 static uint32_t le_audio_demo_sink_zero_frames;
140 static uint32_t samples_received;
141 static uint32_t samples_played;
142 static uint32_t samples_dropped;
143 
144 static btstack_timer_source_t next_packet_timer;
145 
146 // lc3 decoder
147 static bool le_audio_demo_lc3plus_decoder_requested = false;
148 static const btstack_lc3_decoder_t * lc3_decoder;
149 static int16_t pcm[MAX_CHANNELS * MAX_SAMPLES_PER_FRAME];
150 static bool have_pcm[MAX_CHANNELS];
151 
152 static btstack_lc3_decoder_google_t google_decoder_contexts[MAX_CHANNELS];
153 #ifdef HAVE_LC3PLUS
154 static btstack_lc3plus_fraunhofer_decoder_t fraunhofer_decoder_contexts[MAX_CHANNELS];
155 #endif
156 static void * decoder_contexts[MAX_CHANNELS];
157 
158 static void le_audio_connection_sink_playback(int16_t * buffer, uint16_t num_samples){
159     // called from lower-layer but guaranteed to be on main thread
160     log_info("Playback: need %u, have %u", num_samples, btstack_ring_buffer_bytes_available(&playback_buffer) / (le_audio_demo_sink_num_channels * 2));
161 
162     samples_played += num_samples;
163 
164     uint32_t bytes_needed = num_samples * le_audio_demo_sink_num_channels * 2;
165     if (playback_active == false){
166         if (btstack_ring_buffer_bytes_available(&playback_buffer) >= playback_start_threshold_bytes) {
167             log_info("Playback started");
168             playback_active = true;
169         }
170     } else {
171         if (bytes_needed > btstack_ring_buffer_bytes_available(&playback_buffer)) {
172             log_info("Playback underrun");
173             printf("Playback Underrun\n");
174             // empty buffer
175             uint32_t bytes_read;
176             btstack_ring_buffer_read(&playback_buffer, (uint8_t *) buffer, bytes_needed, &bytes_read);
177             playback_active = false;
178         }
179     }
180 
181     if (playback_active){
182         uint32_t bytes_read;
183         btstack_ring_buffer_read(&playback_buffer, (uint8_t *) buffer, bytes_needed, &bytes_read);
184         btstack_assert(bytes_read == bytes_needed);
185     } else {
186         memset(buffer, 0, bytes_needed);
187     }
188 }
189 
190 static void store_samples_in_ringbuffer(void){
191     // check if we have all channels
192     uint8_t channel;
193     for (channel = 0; channel < le_audio_demo_sink_num_channels; channel++){
194         if (have_pcm[channel] == false) return;
195     }
196 #ifdef HAVE_POSIX_FILE_IO
197     // write wav samples
198     wav_writer_write_int16(le_audio_demo_sink_num_channels * le_audio_demo_sink_num_samples_per_frame, pcm);
199 #endif
200 
201     // count for samplerate compensation
202     le_audio_demo_sink_received_samples += le_audio_demo_sink_num_samples_per_frame;
203 
204     // store samples in playback buffer
205     samples_received += le_audio_demo_sink_num_samples_per_frame;
206     uint32_t resampled_frames = btstack_resample_block(&resample_instance, pcm, le_audio_demo_sink_num_samples_per_frame, pcm_resample);
207     uint32_t bytes_to_store = resampled_frames * le_audio_demo_sink_num_channels * 2;
208 
209     if (btstack_ring_buffer_bytes_free(&playback_buffer) >= bytes_to_store) {
210         btstack_ring_buffer_write(&playback_buffer, (uint8_t *) pcm_resample, bytes_to_store);
211         log_info("Samples in playback buffer %5u", btstack_ring_buffer_bytes_available(&playback_buffer) / (le_audio_demo_sink_num_channels * 2));
212     } else {
213         printf("Samples dropped\n");
214         samples_dropped += le_audio_demo_sink_num_samples_per_frame;
215     }
216     memset(have_pcm, 0, sizeof(have_pcm));
217 }
218 
219 static void plc_do(uint8_t stream_index) {
220     // inject packet
221     uint8_t tmp_BEC_detect;
222     uint8_t BFI = 1;
223     uint8_t i;
224     for (i = 0; i < le_audio_demo_sink_num_channels_per_stream; i++){
225         uint8_t effective_channel = stream_index + i;
226         (void) lc3_decoder->decode_signed_16(decoder_contexts[effective_channel], NULL, BFI,
227                                              &pcm[effective_channel], le_audio_demo_sink_num_channels,
228                                              &tmp_BEC_detect);
229         have_pcm[i] = true;
230     }
231     // and store in ringbuffer when PCM for all channels is available
232     store_samples_in_ringbuffer();
233 }
234 
235 //
236 // Perform PLC for packets missing in previous intervals
237 //
238 // assumptions:
239 // - packet sequence number is monotonic increasing
240 // - if packet with seq nr x is received, all packets with smaller seq number are either received or missed
241 static void plc_check(uint16_t packet_sequence_number) {
242     while (group_last_packet_sequence != packet_sequence_number){
243         uint8_t i;
244         for (i=0;i<le_audio_demo_sink_num_streams;i++){
245             // deal with first packet missing. inject silent samples, pcm buffer is memset to zero at start
246             if (stream_last_packet_received[i] == false){
247                 printf_plc("- ISO #%u, very first packet missing\n", i);
248                 have_pcm[i] = true;
249                 store_samples_in_ringbuffer();
250 
251                 stream_last_packet_received[i] = true;
252                 stream_last_packet_sequence[i] = group_last_packet_sequence;
253                 continue;
254             }
255 
256             // missing packet if group sequence counter is higher than stream sequence counter
257             if (btstack_time16_delta(group_last_packet_sequence, stream_last_packet_sequence[i]) > 0) {
258                 printf_plc("- ISO #%u, PLC for %u\n", i, group_last_packet_sequence);
259 #ifndef DEBUG_PLC
260                 log_info("PLC for packet 0x%04x, stream #%u", group_last_packet_sequence, i);
261 #endif
262                 plc_do(i);
263                 btstack_assert((stream_last_packet_sequence[i] + 1) == group_last_packet_sequence);
264                 stream_last_packet_sequence[i] = group_last_packet_sequence;
265             }
266         }
267         group_last_packet_sequence++;
268     }
269 }
270 
271 static void plc_timeout(btstack_timer_source_t * timer) {
272     // Restart timer. This will loose sync with ISO interval, but if we stop caring if we loose that many packets
273     btstack_run_loop_set_timer(timer, plc_timeout_subsequent_ms);
274     btstack_run_loop_set_timer_handler(timer, plc_timeout);
275     btstack_run_loop_add_timer(timer);
276 
277     switch (le_audio_demo_sink_type){
278         case HCI_ISO_TYPE_CIS:
279             // assume no packet received in iso interval => FT packets missed
280             printf_plc("PLC: timeout cis, group %u, FT %u", group_last_packet_sequence, le_audio_demo_sink_flush_timeout);
281             plc_check(group_last_packet_sequence + le_audio_demo_sink_flush_timeout);
282             break;
283         case HCI_ISO_TYPE_BIS:
284             // assume PTO not used => 1 packet missed
285             plc_check(group_last_packet_sequence + 1);
286             break;
287         default:
288             btstack_unreachable();
289             break;
290     }
291 }
292 
293 void le_audio_demo_util_sink_init(const char * filename_wav){
294     le_audio_demo_sink_filename_wav = filename_wav;
295     le_audio_demo_util_sink_state = LE_AUDIO_SINK_INIT;
296 }
297 
298 void le_audio_demo_util_sink_enable_lc3plus(bool enable){
299     le_audio_demo_lc3plus_decoder_requested = enable;
300 }
301 
302 static void setup_lc3_decoder(bool use_lc3plus_decoder){
303     uint8_t channel;
304     for (channel = 0 ; channel < le_audio_demo_sink_num_channels ; channel++){
305         // pick decoder
306         void * decoder_context = NULL;
307 #ifdef HAVE_LC3PLUS
308         if (use_lc3plus_decoder){
309             decoder_context = &fraunhofer_decoder_contexts[channel];
310             lc3_decoder = btstack_lc3plus_fraunhofer_decoder_init_instance(decoder_context);
311         }
312         else
313 #endif
314         {
315             decoder_context = &google_decoder_contexts[channel];
316             lc3_decoder = btstack_lc3_decoder_google_init_instance(decoder_context);
317         }
318         decoder_contexts[channel] = decoder_context;
319         lc3_decoder->configure(decoder_context, le_audio_demo_sink_sampling_frequency_hz, le_audio_demo_sink_frame_duration, le_audio_demo_sink_octets_per_frame);
320     }
321     btstack_assert(le_audio_demo_sink_num_samples_per_frame <= MAX_SAMPLES_PER_FRAME);
322 }
323 
324 void le_audio_demo_util_sink_configure_general(uint8_t num_streams, uint8_t num_channels_per_stream,
325                                                uint32_t sampling_frequency_hz,
326                                                btstack_lc3_frame_duration_t frame_duration, uint16_t octets_per_frame,
327                                                uint32_t iso_interval_1250us) {
328     le_audio_demo_sink_sampling_frequency_hz = sampling_frequency_hz;
329     le_audio_demo_sink_frame_duration = frame_duration;
330     le_audio_demo_sink_octets_per_frame = octets_per_frame;
331     le_audio_demo_sink_iso_interval_1250us = iso_interval_1250us;
332     le_audio_demo_sink_num_streams = num_streams;
333     le_audio_demo_sink_num_channels_per_stream = num_channels_per_stream;
334 
335     sink_receive_streaming = false;
336     le_audio_demo_util_sink_state = LE_AUDIO_SINK_CONFIGURED;
337 
338     le_audio_demo_sink_num_channels = le_audio_demo_sink_num_streams * le_audio_demo_sink_num_channels_per_stream;
339     btstack_assert((le_audio_demo_sink_num_channels == 1) || (le_audio_demo_sink_num_channels == 2));
340 
341     le_audio_demo_sink_lc3_frames = 0;
342 
343     group_last_packet_received = false;
344     uint8_t i;
345     for (i=0;i<MAX_CHANNELS;i++){
346         stream_last_packet_received[i] = false;
347         have_pcm[i] = false;
348     }
349 
350     le_audio_demo_sink_num_samples_per_frame = btstack_lc3_samples_per_frame(le_audio_demo_sink_sampling_frequency_hz, le_audio_demo_sink_frame_duration);
351 
352     // switch to lc3plus if requested and possible
353     bool use_lc3plus_decoder = le_audio_demo_lc3plus_decoder_requested && (frame_duration == BTSTACK_LC3_FRAME_DURATION_10000US);
354 
355     // init decoder
356     setup_lc3_decoder(use_lc3plus_decoder);
357 
358     printf("Configure: %u streams, %u channels per stream, sampling rate %u, samples per frame %u, lc3plus %u\n",
359            num_streams, num_channels_per_stream, sampling_frequency_hz, le_audio_demo_sink_num_samples_per_frame, use_lc3plus_decoder);
360 
361 #ifdef HAVE_POSIX_FILE_IO
362     // create wav file
363     printf("WAV file: %s\n", le_audio_demo_sink_filename_wav);
364     wav_writer_open(le_audio_demo_sink_filename_wav, le_audio_demo_sink_num_channels, le_audio_demo_sink_sampling_frequency_hz);
365 #endif
366 
367     // init playback buffer
368     btstack_ring_buffer_init(&playback_buffer, playback_buffer_storage, PLAYBACK_BUFFER_SIZE);
369 
370     // calc start threshold in bytes for PLAYBACK_START_MS
371     playback_start_threshold_bytes = (sampling_frequency_hz / 1000 * PLAYBACK_START_MS) * le_audio_demo_sink_num_channels * 2;
372 
373     // sample rate compensation
374     le_audio_demo_sink_received_samples = 0;
375 
376     // start playback
377     const btstack_audio_sink_t * sink = btstack_audio_sink_get_instance();
378     if (sink != NULL){
379         btstack_sample_rate_compensation_reset( &sample_rate_compensation, btstack_run_loop_get_time_ms() );
380         btstack_resample_init(&resample_instance, le_audio_demo_sink_num_channels_per_stream);
381         sink->init(le_audio_demo_sink_num_channels, le_audio_demo_sink_sampling_frequency_hz, le_audio_connection_sink_playback);
382         sink->start_stream();
383     }
384 }
385 
386 void le_audio_demo_util_sink_configure_unicast(uint8_t num_streams, uint8_t num_channels_per_stream, uint32_t sampling_frequency_hz,
387                                                btstack_lc3_frame_duration_t frame_duration, uint16_t octets_per_frame,
388                                                uint32_t iso_interval_1250us, uint8_t flush_timeout){
389     le_audio_demo_sink_type = HCI_ISO_TYPE_CIS;
390     le_audio_demo_sink_flush_timeout = flush_timeout;
391 
392     // set playback start: FT * ISO Interval + max(10 ms, 1/2 ISO Interval)
393     uint16_t playback_start_ms = flush_timeout * (iso_interval_1250us * 5 / 4) + btstack_max(10, iso_interval_1250us * 5 / 8);
394     uint16_t playback_start_samples = sampling_frequency_hz / 1000 * playback_start_ms;
395     playback_start_threshold_bytes = playback_start_samples * num_streams * num_channels_per_stream * 2;
396     printf("Playback: start %u ms (%u samples, %u bytes)\n", playback_start_ms, playback_start_samples, playback_start_threshold_bytes);
397 
398     // set subsequent plc timeout: FT * ISO Interval
399     plc_timeout_subsequent_ms = flush_timeout * iso_interval_1250us * 5 / 4;
400 
401     // set initial plc timeout:FT * ISO Interval + 4 ms
402     plc_timeout_initial_ms = plc_timeout_subsequent_ms + 4;
403 
404     printf("PLC: initial timeout    %u ms\n", plc_timeout_initial_ms);
405     printf("PLC: subsequent timeout %u ms\n", plc_timeout_subsequent_ms);
406 
407     le_audio_demo_util_sink_configure_general(num_streams, num_channels_per_stream, sampling_frequency_hz,
408                                               frame_duration, octets_per_frame, iso_interval_1250us);
409 }
410 
411 void le_audio_demo_util_sink_configure_broadcast(uint8_t num_streams, uint8_t num_channels_per_stream, uint32_t sampling_frequency_hz,
412                                                btstack_lc3_frame_duration_t frame_duration, uint16_t octets_per_frame,
413                                                uint32_t iso_interval_1250us, uint8_t pre_transmission_offset) {
414     le_audio_demo_sink_type = HCI_ISO_TYPE_BIS;
415     le_audio_demo_sink_pre_transmission_offset = pre_transmission_offset;
416 
417     // set playback start: ISO Interval + 10 ms
418     uint16_t playback_start_ms = (iso_interval_1250us * 5 / 4) + 10;
419     uint16_t playback_start_samples = sampling_frequency_hz / 1000 * playback_start_ms;
420     playback_start_threshold_bytes = playback_start_samples * num_streams * num_channels_per_stream * 2;
421     printf("Playback: start %u ms (%u samples, %u bytes)\n", playback_start_ms, playback_start_samples, playback_start_threshold_bytes);
422 
423     // set subsequent plc timeout: ISO Interval
424     plc_timeout_subsequent_ms = iso_interval_1250us * 5 / 4;
425 
426     // set initial plc timeout: ISO Interval + 4 ms
427     plc_timeout_initial_ms = plc_timeout_subsequent_ms + 4;
428 
429     printf("PLC: initial timeout    %u ms\n", plc_timeout_initial_ms);
430     printf("PLC: subsequent timeout %u ms\n", plc_timeout_subsequent_ms);
431 
432     le_audio_demo_util_sink_configure_unicast(num_streams, num_channels_per_stream, sampling_frequency_hz, frame_duration,
433                                               octets_per_frame, iso_interval_1250us, pre_transmission_offset);
434 }
435 
436 void le_audio_demo_util_sink_receive(uint8_t stream_index, uint8_t *packet, uint16_t size) {
437 
438     if (le_audio_demo_util_sink_state != LE_AUDIO_SINK_CONFIGURED) return;
439 
440     uint16_t header = little_endian_read_16(packet, 0);
441     hci_con_handle_t con_handle = header & 0x0fff;
442     uint8_t pb_flag = (header >> 12) & 3;
443     uint8_t ts_flag = (header >> 14) & 1;
444     uint16_t iso_load_len = little_endian_read_16(packet, 2);
445 
446     uint16_t offset = 4;
447     uint32_t time_stamp = 0;
448     if (ts_flag){
449         time_stamp = little_endian_read_32(packet, offset);
450         offset += 4;
451     }
452 
453     uint32_t receive_time_ms = btstack_run_loop_get_time_ms();
454 
455     uint16_t packet_sequence_number = little_endian_read_16(packet, offset);
456     offset += 2;
457 
458     uint16_t header_2 = little_endian_read_16(packet, offset);
459     uint16_t iso_sdu_length = header_2 & 0x3fff;
460     uint8_t packet_status_flag = (uint8_t) (header_2 >> 14);
461     offset += 2;
462 
463     // avoid warning for (yet) unused fields
464     UNUSED(con_handle);
465     UNUSED(pb_flag);
466     UNUSED(iso_load_len);
467     UNUSED(packet_status_flag);
468     UNUSED(time_stamp);
469 
470     // start with first packet on first stream
471     if (group_last_packet_received == false){
472         if (stream_index != 0){
473             printf("Ignore first packet for second stream\n");
474             return;
475         }
476         group_last_packet_received = true;
477         group_last_packet_sequence = packet_sequence_number;
478     }
479 
480     if (stream_last_packet_received[stream_index]) {
481         printf_plc("ISO #%u, receive %u\n", stream_index, packet_sequence_number);
482 
483         int16_t packet_sequence_delta = btstack_time16_delta(packet_sequence_number,
484                                                              stream_last_packet_sequence[stream_index]);
485         if (packet_sequence_delta < 1) {
486             // drop delayed packet that had already been generated by PLC
487             printf_plc("- dropping delayed packet. Current sequence number %u, last received or generated by PLC: %u\n",
488                        packet_sequence_number, stream_last_packet_sequence[stream_index]);
489             return;
490         }
491         // simple check
492         if (packet_sequence_number != stream_last_packet_sequence[stream_index] + 1) {
493             printf_plc("- ISO #%u, missing %u\n", stream_index, stream_last_packet_sequence[stream_index] + 1);
494         }
495     } else {
496         printf_plc("ISO %u, first packet seq number %u\n", stream_index, packet_sequence_number);
497         stream_last_packet_received[stream_index] = true;
498     }
499 
500     if (sink_receive_streaming){
501         plc_check(packet_sequence_number);
502     }
503 
504     // either empty packets or num channels * num octets
505     if ((iso_sdu_length != 0) && (iso_sdu_length != le_audio_demo_sink_num_channels_per_stream * le_audio_demo_sink_octets_per_frame)) {
506         printf("ISO Length %u != %u * %u\n", iso_sdu_length, le_audio_demo_sink_num_channels_per_stream, le_audio_demo_sink_octets_per_frame);
507         log_info("ISO Length %u != %u * %u", iso_sdu_length, le_audio_demo_sink_num_channels_per_stream, le_audio_demo_sink_octets_per_frame);
508         return;
509     }
510 
511     const btstack_audio_sink_t * sink = btstack_audio_sink_get_instance();
512     if( (sink != NULL) && (iso_sdu_length>0)) {
513         if (!sink_receive_streaming && playback_active) {
514             btstack_sample_rate_compensation_init(&sample_rate_compensation, receive_time_ms,
515                                                   le_audio_demo_sink_sampling_frequency_hz, FLOAT_TO_Q15(1.f));
516             sink_receive_streaming = true;
517         }
518     }
519 
520     if (iso_sdu_length == 0) {
521         if (sink_receive_streaming){
522             // empty packet -> generate silence
523             memset(pcm, 0, sizeof(pcm));
524             uint8_t i;
525             for (i = 0 ; i < le_audio_demo_sink_num_channels_per_stream ; i++) {
526                 have_pcm[stream_index + i] = true;
527             }
528             le_audio_demo_sink_zero_frames++;
529             // pause detection (1000 ms for 10 ms, 750 ms for 7.5 ms frames)
530             if (le_audio_demo_sink_zero_frames > 100){
531                 printf("Pause detected, stopping audio\n");
532                 log_info("Pause detected, stopping audio");
533                 // pause/reset audio
534                 btstack_ring_buffer_init(&playback_buffer, playback_buffer_storage, PLAYBACK_BUFFER_SIZE);
535                 sink_receive_streaming = false;
536                 playback_active = false;
537             }
538         }
539     } else {
540         // regular packet -> decode codec frame
541         le_audio_demo_sink_zero_frames = 0;
542         uint8_t i;
543         for (i = 0 ; i < le_audio_demo_sink_num_channels_per_stream ; i++){
544             uint8_t tmp_BEC_detect;
545             uint8_t BFI = 0;
546             uint8_t effective_channel = stream_index + i;
547             (void) lc3_decoder->decode_signed_16(decoder_contexts[effective_channel], &packet[offset], BFI,
548                                                  &pcm[effective_channel], le_audio_demo_sink_num_channels,
549                                                  &tmp_BEC_detect);
550             offset += le_audio_demo_sink_octets_per_frame;
551             have_pcm[stream_index + i] = true;
552         }
553     }
554 
555     store_samples_in_ringbuffer();
556 
557     if( (sink != NULL) && (iso_sdu_length>0)) {
558         if( sink_receive_streaming ) {
559             uint32_t resampling_factor = btstack_sample_rate_compensation_update( &sample_rate_compensation, receive_time_ms,
560                                                                                   le_audio_demo_sink_received_samples, sink->get_samplerate() );
561             btstack_resample_set_factor(&resample_instance, resampling_factor);
562             le_audio_demo_sink_received_samples = 0;
563         }
564     }
565 
566     le_audio_demo_sink_lc3_frames++;
567 
568     // PLC
569     btstack_run_loop_remove_timer(&next_packet_timer);
570     btstack_run_loop_set_timer(&next_packet_timer, plc_timeout_initial_ms);
571     btstack_run_loop_set_timer_handler(&next_packet_timer, plc_timeout);
572     btstack_run_loop_add_timer(&next_packet_timer);
573 
574     if (samples_received >= le_audio_demo_sink_sampling_frequency_hz){
575         printf("LC3 Frames: %4u - samples received %5u, played %5u, dropped %5u\n", le_audio_demo_sink_lc3_frames, samples_received, samples_played, samples_dropped);
576         samples_received = 0;
577         samples_dropped  =  0;
578         samples_played = 0;
579     }
580 
581     stream_last_packet_sequence[stream_index] = packet_sequence_number;
582 }
583 
584 /**
585  * @brief Close sink: close wav file, stop playback
586  */
587 void le_audio_demo_util_sink_close(void){
588 #ifdef HAVE_POSIX_FILE_IO
589     printf("Close WAV file\n");
590     wav_writer_close();
591 #endif
592     // stop playback
593     const btstack_audio_sink_t * sink = btstack_audio_sink_get_instance();
594     if (sink != NULL){
595         sink->stop_stream();
596     }
597     le_audio_demo_util_sink_state = LE_AUDIO_SINK_INIT;
598     sink_receive_streaming = false;
599     // stop timer
600     btstack_run_loop_remove_timer(&next_packet_timer);
601 }
602