xref: /btstack/example/le_audio_demo_util_sink.c (revision 8dee1629342465a32b1eda03b06fb703210278d1)
1 /*
2  * Copyright (C) {copyright_year} BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
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9  *    notice, this list of conditions and the following disclaimer.
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12  *    documentation and/or other materials provided with the distribution.
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15  *    from this software without specific prior written permission.
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19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
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22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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36  */
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 const char * le_audio_demo_sink_filename_wav;
97 static btstack_sample_rate_compensation_t sample_rate_compensation;
98 static uint32_t le_audio_demo_sink_received_samples;
99 static btstack_resample_t resample_instance;
100 static bool sink_receive_streaming;
101 
102 static int16_t pcm_resample[MAX_CHANNELS * MAX_SAMPLES_PER_FRAME * 2];
103 
104 
105 static btstack_lc3_frame_duration_t le_audio_demo_sink_frame_duration;
106 static hci_iso_type_t               le_audio_demo_sink_type;
107 
108 static uint32_t le_audio_demo_sink_sampling_frequency_hz;
109 static uint16_t le_audio_demo_sink_num_samples_per_frame;
110 static uint8_t  le_audio_demo_sink_num_streams;
111 static uint8_t  le_audio_demo_sink_num_channels_per_stream;
112 static uint8_t  le_audio_demo_sink_num_channels;
113 static uint16_t le_audio_demo_sink_octets_per_frame;
114 static uint16_t le_audio_demo_sink_iso_interval_1250us;
115 static uint8_t  le_audio_demo_sink_flush_timeout;
116 static uint8_t  le_audio_demo_sink_pre_transmission_offset;
117 
118 // playback
119 static uint16_t              playback_start_threshold_bytes;
120 static bool                  playback_active;
121 static uint8_t               playback_buffer_storage[PLAYBACK_BUFFER_SIZE];
122 static btstack_ring_buffer_t playback_buffer;
123 
124 // PLC
125 static bool     stream_last_packet_received[MAX_CHANNELS];
126 static uint16_t stream_last_packet_sequence[MAX_CHANNELS];
127 static uint16_t group_last_packet_sequence;
128 static bool     group_last_packet_received;
129 static uint16_t plc_timeout_initial_ms;
130 static uint16_t plc_timeout_subsequent_ms;
131 
132 static uint32_t le_audio_demo_sink_lc3_frames;
133 static uint32_t le_audio_demo_sink_zero_frames;
134 static uint32_t samples_received;
135 static uint32_t samples_played;
136 static uint32_t samples_dropped;
137 
138 static btstack_timer_source_t next_packet_timer;
139 
140 // lc3 decoder
141 static bool le_audio_demo_lc3plus_decoder_requested = false;
142 static const btstack_lc3_decoder_t * lc3_decoder;
143 static int16_t pcm[MAX_CHANNELS * MAX_SAMPLES_PER_FRAME];
144 static bool have_pcm[MAX_CHANNELS];
145 
146 static btstack_lc3_decoder_google_t google_decoder_contexts[MAX_CHANNELS];
147 #ifdef HAVE_LC3PLUS
148 static btstack_lc3plus_fraunhofer_decoder_t fraunhofer_decoder_contexts[MAX_CHANNELS];
149 #endif
150 static void * decoder_contexts[MAX_CHANNELS];
151 
152 static void le_audio_connection_sink_playback(int16_t * buffer, uint16_t num_samples){
153     // called from lower-layer but guaranteed to be on main thread
154     log_info("Playback: need %u, have %u", num_samples, btstack_ring_buffer_bytes_available(&playback_buffer) / (le_audio_demo_sink_num_channels * 2));
155 
156     samples_played += num_samples;
157 
158     uint32_t bytes_needed = num_samples * le_audio_demo_sink_num_channels * 2;
159     if (playback_active == false){
160         if (btstack_ring_buffer_bytes_available(&playback_buffer) >= playback_start_threshold_bytes) {
161             log_info("Playback started");
162             playback_active = true;
163         }
164     } else {
165         if (bytes_needed > btstack_ring_buffer_bytes_available(&playback_buffer)) {
166             log_info("Playback underrun");
167             printf("Playback Underrun\n");
168             // empty buffer
169             uint32_t bytes_read;
170             btstack_ring_buffer_read(&playback_buffer, (uint8_t *) buffer, bytes_needed, &bytes_read);
171             playback_active = false;
172         }
173     }
174 
175     if (playback_active){
176         uint32_t bytes_read;
177         btstack_ring_buffer_read(&playback_buffer, (uint8_t *) buffer, bytes_needed, &bytes_read);
178         btstack_assert(bytes_read == bytes_needed);
179     } else {
180         memset(buffer, 0, bytes_needed);
181     }
182 }
183 
184 static void store_samples_in_ringbuffer(void){
185     // check if we have all channels
186     uint8_t channel;
187     for (channel = 0; channel < le_audio_demo_sink_num_channels; channel++){
188         if (have_pcm[channel] == false) return;
189     }
190 #ifdef HAVE_POSIX_FILE_IO
191     // write wav samples
192     wav_writer_write_int16(le_audio_demo_sink_num_channels * le_audio_demo_sink_num_samples_per_frame, pcm);
193 #endif
194 
195     // count for samplerate compensation
196     le_audio_demo_sink_received_samples += le_audio_demo_sink_num_samples_per_frame;
197 
198     // store samples in playback buffer
199     samples_received += le_audio_demo_sink_num_samples_per_frame;
200     uint32_t resampled_frames = btstack_resample_block(&resample_instance, pcm, le_audio_demo_sink_num_samples_per_frame, pcm_resample);
201     uint32_t bytes_to_store = resampled_frames * le_audio_demo_sink_num_channels * 2;
202 
203     if (btstack_ring_buffer_bytes_free(&playback_buffer) >= bytes_to_store) {
204         btstack_ring_buffer_write(&playback_buffer, (uint8_t *) pcm_resample, bytes_to_store);
205         log_info("Samples in playback buffer %5u", btstack_ring_buffer_bytes_available(&playback_buffer) / (le_audio_demo_sink_num_channels * 2));
206     } else {
207         printf("Samples dropped\n");
208         samples_dropped += le_audio_demo_sink_num_samples_per_frame;
209     }
210     memset(have_pcm, 0, sizeof(have_pcm));
211 }
212 
213 static void plc_do(uint8_t stream_index) {
214     // inject packet
215     uint8_t tmp_BEC_detect;
216     uint8_t BFI = 1;
217     uint8_t i;
218     for (i = 0; i < le_audio_demo_sink_num_channels_per_stream; i++){
219         uint8_t effective_channel = stream_index + i;
220         (void) lc3_decoder->decode_signed_16(decoder_contexts[effective_channel], NULL, BFI,
221                                              &pcm[effective_channel], le_audio_demo_sink_num_channels,
222                                              &tmp_BEC_detect);
223         have_pcm[i] = true;
224     }
225     // and store in ringbuffer when PCM for all channels is available
226     store_samples_in_ringbuffer();
227 }
228 
229 //
230 // Perform PLC for packets missing in previous intervals
231 //
232 // assumptions:
233 // - packet sequence number is monotonic increasing
234 // - if packet with seq nr x is received, all packets with smaller seq number are either received or missed
235 static void plc_check(uint16_t packet_sequence_number) {
236     while (group_last_packet_sequence != packet_sequence_number){
237         uint8_t i;
238         for (i=0;i<le_audio_demo_sink_num_streams;i++){
239             // deal with first packet missing. inject silent samples, pcm buffer is memset to zero at start
240             if (stream_last_packet_received[i] == false){
241                 printf_plc("- ISO #%u, very first packet missing\n", i);
242                 have_pcm[i] = true;
243                 store_samples_in_ringbuffer();
244 
245                 stream_last_packet_received[i] = true;
246                 stream_last_packet_sequence[i] = group_last_packet_sequence;
247                 continue;
248             }
249 
250             // missing packet if group sequence counter is higher than stream sequence counter
251             if (btstack_time16_delta(group_last_packet_sequence, stream_last_packet_sequence[i]) > 0) {
252                 printf_plc("- ISO #%u, PLC for %u\n", i, group_last_packet_sequence);
253 #ifndef DEBUG_PLC
254                 log_info("PLC for packet 0x%04x, stream #%u", group_last_packet_sequence, i);
255 #endif
256                 plc_do(i);
257                 btstack_assert((stream_last_packet_sequence[i] + 1) == group_last_packet_sequence);
258                 stream_last_packet_sequence[i] = group_last_packet_sequence;
259             }
260         }
261         group_last_packet_sequence++;
262     }
263 }
264 
265 static void plc_timeout(btstack_timer_source_t * timer) {
266     // Restart timer. This will loose sync with ISO interval, but if we stop caring if we loose that many packets
267     btstack_run_loop_set_timer(timer, plc_timeout_subsequent_ms);
268     btstack_run_loop_set_timer_handler(timer, plc_timeout);
269     btstack_run_loop_add_timer(timer);
270 
271     switch (le_audio_demo_sink_type){
272         case HCI_ISO_TYPE_CIS:
273             // assume no packet received in iso interval => FT packets missed
274             printf_plc("PLC: timeout cis, group %u, FT %u", group_last_packet_sequence, le_audio_demo_sink_flush_timeout);
275             plc_check(group_last_packet_sequence + le_audio_demo_sink_flush_timeout);
276             break;
277         case HCI_ISO_TYPE_BIS:
278             // assume PTO not used => 1 packet missed
279             plc_check(group_last_packet_sequence + 1);
280             break;
281         default:
282             btstack_unreachable();
283             break;
284     }
285 }
286 
287 void le_audio_demo_util_sink_init(const char * filename_wav){
288     le_audio_demo_sink_filename_wav = filename_wav;
289 }
290 
291 void le_audio_demo_util_sink_enable_lc3plus(bool enable){
292     le_audio_demo_lc3plus_decoder_requested = enable;
293 }
294 
295 static void setup_lc3_decoder(bool use_lc3plus_decoder){
296     uint8_t channel;
297     for (channel = 0 ; channel < le_audio_demo_sink_num_channels ; channel++){
298         // pick decoder
299         void * decoder_context = NULL;
300 #ifdef HAVE_LC3PLUS
301         if (use_lc3plus_decoder){
302             decoder_context = &fraunhofer_decoder_contexts[channel];
303             lc3_decoder = btstack_lc3plus_fraunhofer_decoder_init_instance(decoder_context);
304         }
305         else
306 #endif
307         {
308             decoder_context = &google_decoder_contexts[channel];
309             lc3_decoder = btstack_lc3_decoder_google_init_instance(decoder_context);
310         }
311         decoder_contexts[channel] = decoder_context;
312         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);
313     }
314     btstack_assert(le_audio_demo_sink_num_samples_per_frame <= MAX_SAMPLES_PER_FRAME);
315 }
316 
317 void le_audio_demo_util_sink_configure_general(uint8_t num_streams, uint8_t num_channels_per_stream,
318                                                uint32_t sampling_frequency_hz,
319                                                btstack_lc3_frame_duration_t frame_duration, uint16_t octets_per_frame,
320                                                uint32_t iso_interval_1250us) {
321     le_audio_demo_sink_sampling_frequency_hz = sampling_frequency_hz;
322     le_audio_demo_sink_frame_duration = frame_duration;
323     le_audio_demo_sink_octets_per_frame = octets_per_frame;
324     le_audio_demo_sink_iso_interval_1250us = iso_interval_1250us;
325     le_audio_demo_sink_num_streams = num_streams;
326     le_audio_demo_sink_num_channels_per_stream = num_channels_per_stream;
327 
328     sink_receive_streaming = false;
329 
330     le_audio_demo_sink_num_channels = le_audio_demo_sink_num_streams * le_audio_demo_sink_num_channels_per_stream;
331     btstack_assert((le_audio_demo_sink_num_channels == 1) || (le_audio_demo_sink_num_channels == 2));
332 
333     le_audio_demo_sink_lc3_frames = 0;
334 
335     group_last_packet_received = false;
336     uint8_t i;
337     for (i=0;i<MAX_CHANNELS;i++){
338         stream_last_packet_received[i] = false;
339         have_pcm[i] = false;
340     }
341 
342     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);
343 
344     // switch to lc3plus if requested and possible
345     bool use_lc3plus_decoder = le_audio_demo_lc3plus_decoder_requested && (frame_duration == BTSTACK_LC3_FRAME_DURATION_10000US);
346 
347     // init decoder
348     setup_lc3_decoder(use_lc3plus_decoder);
349 
350     printf("Configure: %u streams, %u channels per stream, sampling rate %u, samples per frame %u, lc3plus %u\n",
351            num_streams, num_channels_per_stream, sampling_frequency_hz, le_audio_demo_sink_num_samples_per_frame, use_lc3plus_decoder);
352 
353 #ifdef HAVE_POSIX_FILE_IO
354     // create wav file
355     printf("WAV file: %s\n", le_audio_demo_sink_filename_wav);
356     wav_writer_open(le_audio_demo_sink_filename_wav, le_audio_demo_sink_num_channels, le_audio_demo_sink_sampling_frequency_hz);
357 #endif
358 
359     // init playback buffer
360     btstack_ring_buffer_init(&playback_buffer, playback_buffer_storage, PLAYBACK_BUFFER_SIZE);
361 
362     // calc start threshold in bytes for PLAYBACK_START_MS
363     playback_start_threshold_bytes = (sampling_frequency_hz / 1000 * PLAYBACK_START_MS) * le_audio_demo_sink_num_channels * 2;
364 
365     // sample rate compensation
366     le_audio_demo_sink_received_samples = 0;
367 
368     // start playback
369     const btstack_audio_sink_t * sink = btstack_audio_sink_get_instance();
370     if (sink != NULL){
371         btstack_sample_rate_compensation_reset( &sample_rate_compensation, btstack_run_loop_get_time_ms() );
372         btstack_resample_init(&resample_instance, le_audio_demo_sink_num_channels_per_stream);
373         sink->init(le_audio_demo_sink_num_channels, le_audio_demo_sink_sampling_frequency_hz, le_audio_connection_sink_playback);
374         sink->start_stream();
375     }
376 }
377 
378 void le_audio_demo_util_sink_configure_unicast(uint8_t num_streams, uint8_t num_channels_per_stream, uint32_t sampling_frequency_hz,
379                                                btstack_lc3_frame_duration_t frame_duration, uint16_t octets_per_frame,
380                                                uint32_t iso_interval_1250us, uint8_t flush_timeout){
381     le_audio_demo_sink_type = HCI_ISO_TYPE_CIS;
382     le_audio_demo_sink_flush_timeout = flush_timeout;
383 
384     // set playback start: FT * ISO Interval + max(10 ms, 1/2 ISO Interval)
385     uint16_t playback_start_ms = flush_timeout * (iso_interval_1250us * 5 / 4) + btstack_max(10, iso_interval_1250us * 5 / 8);
386     uint16_t playback_start_samples = sampling_frequency_hz / 1000 * playback_start_ms;
387     playback_start_threshold_bytes = playback_start_samples * num_streams * num_channels_per_stream * 2;
388     printf("Playback: start %u ms (%u samples, %u bytes)\n", playback_start_ms, playback_start_samples, playback_start_threshold_bytes);
389 
390     // set subsequent plc timeout: FT * ISO Interval
391     plc_timeout_subsequent_ms = flush_timeout * iso_interval_1250us * 5 / 4;
392 
393     // set initial plc timeout:FT * ISO Interval + 4 ms
394     plc_timeout_initial_ms = plc_timeout_subsequent_ms + 4;
395 
396     printf("PLC: initial timeout    %u ms\n", plc_timeout_initial_ms);
397     printf("PLC: subsequent timeout %u ms\n", plc_timeout_subsequent_ms);
398 
399     le_audio_demo_util_sink_configure_general(num_streams, num_channels_per_stream, sampling_frequency_hz,
400                                               frame_duration, octets_per_frame, iso_interval_1250us);
401 }
402 
403 void le_audio_demo_util_sink_configure_broadcast(uint8_t num_streams, uint8_t num_channels_per_stream, uint32_t sampling_frequency_hz,
404                                                btstack_lc3_frame_duration_t frame_duration, uint16_t octets_per_frame,
405                                                uint32_t iso_interval_1250us, uint8_t pre_transmission_offset) {
406     le_audio_demo_sink_type = HCI_ISO_TYPE_BIS;
407     le_audio_demo_sink_pre_transmission_offset = pre_transmission_offset;
408 
409     // set playback start: ISO Interval + 10 ms
410     uint16_t playback_start_ms = (iso_interval_1250us * 5 / 4) + 10;
411     uint16_t playback_start_samples = sampling_frequency_hz / 1000 * playback_start_ms;
412     playback_start_threshold_bytes = playback_start_samples * num_streams * num_channels_per_stream * 2;
413     printf("Playback: start %u ms (%u samples, %u bytes)\n", playback_start_ms, playback_start_samples, playback_start_threshold_bytes);
414 
415     // set subsequent plc timeout: ISO Interval
416     plc_timeout_subsequent_ms = iso_interval_1250us * 5 / 4;
417 
418     // set initial plc timeout: ISO Interval + 4 ms
419     plc_timeout_initial_ms = plc_timeout_subsequent_ms + 4;
420 
421     printf("PLC: initial timeout    %u ms\n", plc_timeout_initial_ms);
422     printf("PLC: subsequent timeout %u ms\n", plc_timeout_subsequent_ms);
423 
424     le_audio_demo_util_sink_configure_unicast(num_streams, num_channels_per_stream, sampling_frequency_hz, frame_duration,
425                                               octets_per_frame, iso_interval_1250us, pre_transmission_offset);
426 }
427 
428 void le_audio_demo_util_sink_receive(uint8_t stream_index, uint8_t *packet, uint16_t size) {
429     uint16_t header = little_endian_read_16(packet, 0);
430     hci_con_handle_t con_handle = header & 0x0fff;
431     uint8_t pb_flag = (header >> 12) & 3;
432     uint8_t ts_flag = (header >> 14) & 1;
433     uint16_t iso_load_len = little_endian_read_16(packet, 2);
434 
435     uint16_t offset = 4;
436     uint32_t time_stamp = 0;
437     if (ts_flag){
438         time_stamp = little_endian_read_32(packet, offset);
439         offset += 4;
440     }
441 
442     uint32_t receive_time_ms = btstack_run_loop_get_time_ms();
443 
444     uint16_t packet_sequence_number = little_endian_read_16(packet, offset);
445     offset += 2;
446 
447     uint16_t header_2 = little_endian_read_16(packet, offset);
448     uint16_t iso_sdu_length = header_2 & 0x3fff;
449     uint8_t packet_status_flag = (uint8_t) (header_2 >> 14);
450     offset += 2;
451 
452     // avoid warning for (yet) unused fields
453     UNUSED(con_handle);
454     UNUSED(pb_flag);
455     UNUSED(iso_load_len);
456     UNUSED(packet_status_flag);
457 
458     // start with first packet on first stream
459     if (group_last_packet_received == false){
460         if (stream_index != 0){
461             printf("Ignore first packet for second stream\n");
462             return;
463         }
464         group_last_packet_received = true;
465         group_last_packet_sequence = packet_sequence_number;
466     }
467 
468     if (stream_last_packet_received[stream_index]) {
469         printf_plc("ISO #%u, receive %u\n", stream_index, packet_sequence_number);
470 
471         int16_t packet_sequence_delta = btstack_time16_delta(packet_sequence_number,
472                                                              stream_last_packet_sequence[stream_index]);
473         if (packet_sequence_delta < 1) {
474             // drop delayed packet that had already been generated by PLC
475             printf_plc("- dropping delayed packet. Current sequence number %u, last received or generated by PLC: %u\n",
476                        packet_sequence_number, stream_last_packet_sequence[stream_index]);
477             return;
478         }
479         // simple check
480         if (packet_sequence_number != stream_last_packet_sequence[stream_index] + 1) {
481             printf_plc("- ISO #%u, missing %u\n", stream_index, stream_last_packet_sequence[stream_index] + 1);
482         }
483     } else {
484         printf_plc("ISO %u, first packet seq number %u\n", stream_index, packet_sequence_number);
485         stream_last_packet_received[stream_index] = true;
486     }
487 
488     if (sink_receive_streaming){
489         plc_check(packet_sequence_number);
490     }
491 
492     // either empty packets or num channels * num octets
493     if ((iso_sdu_length != 0) && (iso_sdu_length != le_audio_demo_sink_num_channels_per_stream * le_audio_demo_sink_octets_per_frame)) {
494         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);
495         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);
496         return;
497     }
498 
499     const btstack_audio_sink_t * sink = btstack_audio_sink_get_instance();
500     if( (sink != NULL) && (iso_sdu_length>0)) {
501         if (!sink_receive_streaming && playback_active) {
502             btstack_sample_rate_compensation_init(&sample_rate_compensation, receive_time_ms,
503                                                   le_audio_demo_sink_sampling_frequency_hz, FLOAT_TO_Q15(1.f));
504             sink_receive_streaming = true;
505         }
506     }
507 
508     if (iso_sdu_length == 0) {
509         if (sink_receive_streaming){
510             // empty packet -> generate silence
511             memset(pcm, 0, sizeof(pcm));
512             uint8_t i;
513             for (i = 0 ; i < le_audio_demo_sink_num_channels_per_stream ; i++) {
514                 have_pcm[stream_index + i] = true;
515             }
516             le_audio_demo_sink_zero_frames++;
517             // pause detection (1000 ms for 10 ms, 750 ms for 7.5 ms frames)
518             if (le_audio_demo_sink_zero_frames > 100){
519                 printf("Pause detected, stopping audio\n");
520                 log_info("Pause detected, stopping audio");
521                 // pause/reset audio
522                 btstack_ring_buffer_init(&playback_buffer, playback_buffer_storage, PLAYBACK_BUFFER_SIZE);
523                 sink_receive_streaming = false;
524                 playback_active = false;
525             }
526         }
527     } else {
528         // regular packet -> decode codec frame
529         le_audio_demo_sink_zero_frames = 0;
530         uint8_t i;
531         for (i = 0 ; i < le_audio_demo_sink_num_channels_per_stream ; i++){
532             uint8_t tmp_BEC_detect;
533             uint8_t BFI = 0;
534             uint8_t effective_channel = stream_index + i;
535             (void) lc3_decoder->decode_signed_16(decoder_contexts[effective_channel], &packet[offset], BFI,
536                                                  &pcm[effective_channel], le_audio_demo_sink_num_channels,
537                                                  &tmp_BEC_detect);
538             offset += le_audio_demo_sink_octets_per_frame;
539             have_pcm[stream_index + i] = true;
540         }
541     }
542 
543     store_samples_in_ringbuffer();
544 
545     if( (sink != NULL) && (iso_sdu_length>0)) {
546         if( sink_receive_streaming ) {
547             uint32_t resampling_factor = btstack_sample_rate_compensation_update( &sample_rate_compensation, receive_time_ms,
548                                                                                   le_audio_demo_sink_received_samples, sink->get_samplerate() );
549             btstack_resample_set_factor(&resample_instance, resampling_factor);
550             le_audio_demo_sink_received_samples = 0;
551         }
552     }
553 
554     le_audio_demo_sink_lc3_frames++;
555 
556     // PLC
557     btstack_run_loop_remove_timer(&next_packet_timer);
558     btstack_run_loop_set_timer(&next_packet_timer, plc_timeout_initial_ms);
559     btstack_run_loop_set_timer_handler(&next_packet_timer, plc_timeout);
560     btstack_run_loop_add_timer(&next_packet_timer);
561 
562     if (samples_received >= le_audio_demo_sink_sampling_frequency_hz){
563         printf("LC3 Frames: %4u - samples received %5u, played %5u, dropped %5u\n", le_audio_demo_sink_lc3_frames, samples_received, samples_played, samples_dropped);
564         samples_received = 0;
565         samples_dropped  =  0;
566         samples_played = 0;
567     }
568 
569     stream_last_packet_sequence[stream_index] = packet_sequence_number;
570 }
571 
572 /**
573  * @brief Close sink: close wav file, stop playback
574  */
575 void le_audio_demo_util_sink_close(void){
576 #ifdef HAVE_POSIX_FILE_IO
577     printf("Close WAV file\n");
578     wav_writer_close();
579 #endif
580     // stop playback
581     const btstack_audio_sink_t * sink = btstack_audio_sink_get_instance();
582     if (sink != NULL){
583         sink->stop_stream();
584     }
585     sink_receive_streaming = false;
586     // stop timer
587     btstack_run_loop_remove_timer(&next_packet_timer);
588 }
589