xref: /btstack/src/classic/btstack_sbc_decoder_bluedroid.c (revision 360d44f609bbebbf954ea85f461752a6b07644cd)
1 /*
2  * Copyright (C) 2014 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__ "btstack_sbc_decoder_bluedroid.c"
39 
40 // *****************************************************************************
41 //
42 // SBC decoder based on Bluedroid library
43 //
44 // *****************************************************************************
45 
46 #include "btstack_config.h"
47 
48 #include <stdint.h>
49 
50 #include <stdlib.h>
51 #include <string.h>
52 
53 #ifdef LOG_FRAME_STATUS
54 #include <stdio.h>
55 #endif
56 
57 #include "btstack_debug.h"
58 #include "btstack_util.h"
59 #include "btstack_sbc.h"
60 #include "btstack_sbc_plc.h"
61 
62 #include "oi_codec_sbc.h"
63 #include "oi_assert.h"
64 
65 #define mSBC_SYNCWORD 0xad
66 #define SBC_SYNCWORD 0x9c
67 #define SBC_MAX_CHANNELS 2
68 // #define LOG_FRAME_STATUS
69 
70 #define DECODER_DATA_SIZE (SBC_MAX_CHANNELS*SBC_MAX_BLOCKS*SBC_MAX_BANDS * 4 + SBC_CODEC_MIN_FILTER_BUFFERS*SBC_MAX_BANDS*SBC_MAX_CHANNELS * 2)
71 
72 typedef struct {
73     OI_UINT32 bytes_in_frame_buffer;
74     OI_CODEC_SBC_DECODER_CONTEXT decoder_context;
75 
76     uint8_t   frame_buffer[SBC_MAX_FRAME_LEN];
77     int16_t   pcm_plc_data[SBC_MAX_CHANNELS * SBC_MAX_BANDS * SBC_MAX_BLOCKS];
78     int16_t   pcm_data[SBC_MAX_CHANNELS * SBC_MAX_BANDS * SBC_MAX_BLOCKS];
79     uint32_t  pcm_bytes;
80     OI_UINT32 decoder_data[(DECODER_DATA_SIZE+3)/4];
81     int       first_good_frame_found;
82     int       h2_sequence_nr;
83     uint16_t  msbc_bad_bytes;
84 } bludroid_decoder_state_t;
85 
86 static btstack_sbc_decoder_state_t * sbc_decoder_state_singleton = NULL;
87 static bludroid_decoder_state_t bd_decoder_state;
88 
89 // Testing only - START
90 static int plc_enabled = 1;
91 static int corrupt_frame_period = -1;
92 // Testing - STOP
93 
94 void btstack_sbc_decoder_test_set_plc_enabled(int enabled){
95     plc_enabled = enabled;
96 }
97 
98 void btstack_sbc_decoder_test_simulate_corrupt_frames(int period){
99     corrupt_frame_period = period;
100 }
101 
102 static int find_sequence_of_zeros(const OI_BYTE *frame_data, OI_UINT32 frame_bytes, int seq_length){
103     int zero_seq_count = 0;
104     unsigned int i;
105     for (i=0; i<frame_bytes; i++){
106         if (frame_data[i] == 0) {
107             zero_seq_count++;
108             if (zero_seq_count >= seq_length) return zero_seq_count;
109         } else {
110             zero_seq_count = 0;
111         }
112     }
113     return 0;
114 }
115 
116 // returns position of mSBC sync word
117 static int find_h2_sync(const OI_BYTE *frame_data, OI_UINT32 frame_bytes, int * sync_word_nr){
118     int syncword = mSBC_SYNCWORD;
119     uint8_t h2_first_byte = 0;
120     uint8_t h2_second_byte = 0;
121 
122     unsigned int i;
123     for (i=0; i<frame_bytes; i++){
124         if (frame_data[i] == syncword) {
125             // check: first byte == 1
126             if (h2_first_byte == 1) {
127                 // check lower nibble of second byte == 0x08
128                 uint8_t ln = h2_second_byte & 0x0F;
129                 if (ln == 8) {
130                     // check if bits 0+2 == bits 1+3
131                     uint8_t hn = h2_second_byte >> 4;
132                     if  ( ((hn>>1) & 0x05) == (hn & 0x05) ) {
133                         *sync_word_nr = ((hn & 0x04) >> 1) | (hn & 0x01);
134                         return i;
135                     }
136                 }
137             }
138         }
139         h2_first_byte = h2_second_byte;
140         h2_second_byte = frame_data[i];
141     }
142     return -1;
143 }
144 
145 int btstack_sbc_decoder_num_samples_per_frame(btstack_sbc_decoder_state_t * state){
146     bludroid_decoder_state_t * decoder_state = (bludroid_decoder_state_t *) state->decoder_state;
147     return decoder_state->decoder_context.common.frameInfo.nrof_blocks * decoder_state->decoder_context.common.frameInfo.nrof_subbands;
148 }
149 
150 int btstack_sbc_decoder_num_channels(btstack_sbc_decoder_state_t * state){
151     bludroid_decoder_state_t * decoder_state = (bludroid_decoder_state_t *) state->decoder_state;
152     return decoder_state->decoder_context.common.frameInfo.nrof_channels;
153 }
154 
155 int btstack_sbc_decoder_sample_rate(btstack_sbc_decoder_state_t * state){
156     bludroid_decoder_state_t * decoder_state = (bludroid_decoder_state_t *) state->decoder_state;
157     return decoder_state->decoder_context.common.frameInfo.frequency;
158 }
159 
160 #ifdef OI_DEBUG
161 void OI_AssertFail(const char* file, int line, const char* reason){
162     log_error("AssertFail file %s, line %d, reason %s", file, line, reason);
163 }
164 #endif
165 
166 void btstack_sbc_decoder_init(btstack_sbc_decoder_state_t * state, btstack_sbc_mode_t mode, void (*callback)(int16_t * data, int num_samples, int num_channels, int sample_rate, void * context), void * context){
167     if (sbc_decoder_state_singleton && (sbc_decoder_state_singleton != state) ){
168         log_error("SBC decoder: different sbc decoder state already registered");
169     }
170     OI_STATUS status = OI_STATUS_SUCCESS;
171     switch (mode){
172         case SBC_MODE_STANDARD:
173             // note: we always request stereo output, even for mono input
174             status = OI_CODEC_SBC_DecoderReset(&(bd_decoder_state.decoder_context), bd_decoder_state.decoder_data, sizeof(bd_decoder_state.decoder_data), 2, 2, FALSE);
175             break;
176         case SBC_MODE_mSBC:
177             status = OI_CODEC_mSBC_DecoderReset(&(bd_decoder_state.decoder_context), bd_decoder_state.decoder_data, sizeof(bd_decoder_state.decoder_data));
178             break;
179         default:
180             break;
181     }
182 
183     if (status != OI_STATUS_SUCCESS){
184         log_error("SBC decoder: error during reset %d\n", status);
185     }
186 
187     sbc_decoder_state_singleton = state;
188 
189     bd_decoder_state.bytes_in_frame_buffer = 0;
190     bd_decoder_state.pcm_bytes = sizeof(bd_decoder_state.pcm_data);
191     bd_decoder_state.h2_sequence_nr = -1;
192     bd_decoder_state.first_good_frame_found = 0;
193 
194     memset(state, 0, sizeof(btstack_sbc_decoder_state_t));
195     state->handle_pcm_data = callback;
196     state->mode = mode;
197     state->context = context;
198     state->decoder_state = &bd_decoder_state;
199     btstack_sbc_plc_init(&state->plc_state);
200 }
201 
202 static void append_received_sbc_data(bludroid_decoder_state_t * state, const uint8_t * buffer, int size){
203     int numFreeBytes = sizeof(state->frame_buffer) - state->bytes_in_frame_buffer;
204 
205     if (size > numFreeBytes){
206         log_error("SBC data: more bytes read %u than free bytes in buffer %u", size, numFreeBytes);
207     }
208 
209     (void)memcpy(state->frame_buffer + state->bytes_in_frame_buffer, buffer,
210                  size);
211     state->bytes_in_frame_buffer += size;
212 }
213 
214 static void btstack_sbc_decoder_bluedroid_simulate_error(const OI_BYTE *frame_data) {
215     static int frame_count = 0;
216     if (corrupt_frame_period > 0){
217         frame_count++;
218 
219         if ((frame_count % corrupt_frame_period) == 0){
220             *(uint8_t*)&frame_data[5] = 0;
221             frame_count = 0;
222         }
223     }
224 }
225 
226 static void btstack_sbc_decoder_process_sbc_data(btstack_sbc_decoder_state_t * state, const uint8_t * buffer, int size){
227     bludroid_decoder_state_t * decoder_state = (bludroid_decoder_state_t*)state->decoder_state;
228     int input_bytes_to_process = size;
229     int keep_decoding = 1;
230 
231     while (keep_decoding) {
232         // Fill decoder_state->frame_buffer as much as possible.
233         int bytes_free_in_frame_buffer = SBC_MAX_FRAME_LEN - decoder_state->bytes_in_frame_buffer;
234         int bytes_to_append = btstack_min(input_bytes_to_process, bytes_free_in_frame_buffer);
235         if (bytes_to_append){
236             append_received_sbc_data(decoder_state, buffer, bytes_to_append);
237             buffer += bytes_to_append;
238             input_bytes_to_process -= bytes_to_append;
239         }
240 
241         // Decode the next frame in decoder_state->frame_buffer.
242         int bytes_in_frame_buffer_before_decoding = decoder_state->bytes_in_frame_buffer;
243         const OI_BYTE *frame_data = decoder_state->frame_buffer;
244         OI_UINT32 frame_data_len = decoder_state->bytes_in_frame_buffer;
245         OI_STATUS status = OI_CODEC_SBC_DecodeFrame(&(decoder_state->decoder_context),
246                                                     &frame_data,
247                                                     &frame_data_len,
248                                                     decoder_state->pcm_plc_data,
249                                                     &(decoder_state->pcm_bytes));
250         uint16_t bytes_processed = bytes_in_frame_buffer_before_decoding - frame_data_len;
251 
252         // testing only - corrupt frame periodically
253         btstack_sbc_decoder_bluedroid_simulate_error(frame_data);
254 
255         // Handle decoding result.
256         switch(status){
257             case OI_STATUS_SUCCESS:
258             case OI_CODEC_SBC_PARTIAL_DECODE:
259                 state->handle_pcm_data(decoder_state->pcm_plc_data,
260                                        btstack_sbc_decoder_num_samples_per_frame(state),
261                                        btstack_sbc_decoder_num_channels(state),
262                                        btstack_sbc_decoder_sample_rate(state), state->context);
263                 state->good_frames_nr++;
264                 break;
265 
266             case OI_CODEC_SBC_NOT_ENOUGH_HEADER_DATA:
267             case OI_CODEC_SBC_NOT_ENOUGH_BODY_DATA:
268             case OI_CODEC_SBC_NOT_ENOUGH_AUDIO_DATA:
269                 if (input_bytes_to_process > 0){
270                     // Should never occur: The SBC codec claims there is not enough bytes in the frame_buffer,
271                     // but the frame_buffer was full. (The frame_buffer is always full before decoding when input_bytes_to_process > 0.)
272                     // Clear frame_buffer.
273                     log_info("SBC decode: frame_buffer too small for frame");
274                     bytes_processed = bytes_in_frame_buffer_before_decoding;
275                 } else {
276                     // Exit decode loop, because there is not enough data in frame_buffer to decode the next frame.
277                     keep_decoding = 0;
278                 }
279                 break;
280 
281             case OI_CODEC_SBC_NO_SYNCWORD:
282                 // This means the entire frame_buffer did not contain the syncword.
283                 // Discard the frame_buffer contents.
284                 log_info("SBC decode: no syncword found");
285                 bytes_processed = bytes_in_frame_buffer_before_decoding;
286                 break;
287 
288             case OI_CODEC_SBC_CHECKSUM_MISMATCH:
289                 // The next frame is somehow corrupt.
290                 log_info("SBC decode: checksum error");
291                 // Did the codec consume any bytes?
292                 if (bytes_processed > 0){
293                     // Good. Nothing to do.
294                 } else {
295                     // Skip the bogus frame by skipping the header.
296                     bytes_processed = 1;
297                 }
298                 break;
299 
300             case OI_STATUS_INVALID_PARAMETERS:
301                 // This caused by corrupt frames.
302                 // The codec apparently does not recover from this.
303                 // Re-initialize the codec.
304                 log_info("SBC decode: invalid parameters: resetting codec");
305                 if (OI_CODEC_SBC_DecoderReset(&(bd_decoder_state.decoder_context), bd_decoder_state.decoder_data, sizeof(bd_decoder_state.decoder_data), 2, 2, FALSE) != OI_STATUS_SUCCESS){
306                     log_info("SBC decode: resetting codec failed");
307 
308                 }
309                 break;
310             default:
311                 // Anything else went wrong.
312                 // Skip a few bytes and try again.
313                 bytes_processed = 1;
314                 log_info("SBC decode: unknown status %d", status);
315                 break;
316         }
317 
318         // Remove decoded frame from decoder_state->frame_buffer.
319         if (bytes_processed > bytes_in_frame_buffer_before_decoding) {
320             bytes_processed = bytes_in_frame_buffer_before_decoding;
321         }
322         memmove(decoder_state->frame_buffer, decoder_state->frame_buffer + bytes_processed, bytes_in_frame_buffer_before_decoding - bytes_processed);
323         decoder_state->bytes_in_frame_buffer -= bytes_processed;
324     }
325 }
326 
327 
328 static void btstack_sbc_decoder_insert_missing_frames(btstack_sbc_decoder_state_t *state) {
329     bludroid_decoder_state_t * decoder_state = (bludroid_decoder_state_t*)state->decoder_state;
330     const unsigned int MSBC_FRAME_SIZE = 60;
331 
332     while (decoder_state->first_good_frame_found && (decoder_state->msbc_bad_bytes >= MSBC_FRAME_SIZE)){
333 
334         decoder_state->msbc_bad_bytes -= MSBC_FRAME_SIZE;
335         state->bad_frames_nr++;
336 
337         // prepare zero signal frame
338         const OI_BYTE * frame_data  = btstack_sbc_plc_zero_signal_frame();
339         OI_UINT32 bytes_in_frame_buffer = 57;
340 
341         // log_info("Trace bad frame generator, bad bytes %u", decoder_state->msbc_bad_bytes);
342         OI_STATUS status = status = OI_CODEC_SBC_DecodeFrame(&(decoder_state->decoder_context),
343                                             &frame_data,
344                                             &bytes_in_frame_buffer,
345                                             decoder_state->pcm_plc_data,
346                                             &(decoder_state->pcm_bytes));
347 
348         if (status) {
349             log_error("SBC decoder for ZIR frame: error %d\n", status);
350         }
351 
352         if (bytes_in_frame_buffer){
353             log_error("PLC: not all bytes of zero frame processed, left %u\n", (unsigned int) bytes_in_frame_buffer);
354         }
355 
356         if (plc_enabled) {
357             btstack_sbc_plc_bad_frame(&state->plc_state, decoder_state->pcm_plc_data, decoder_state->pcm_data);
358         } else {
359             (void)memcpy(decoder_state->pcm_data,
360                          decoder_state->pcm_plc_data,
361                          decoder_state->pcm_bytes);
362         }
363 
364         state->handle_pcm_data(decoder_state->pcm_data,
365                             btstack_sbc_decoder_num_samples_per_frame(state),
366                             btstack_sbc_decoder_num_channels(state),
367                             btstack_sbc_decoder_sample_rate(state), state->context);
368     }
369 }
370 
371 static void btstack_sbc_decoder_drop_processed_bytes(bludroid_decoder_state_t * decoder_state, uint16_t bytes_processed){
372     memmove(decoder_state->frame_buffer, decoder_state->frame_buffer + bytes_processed, decoder_state->bytes_in_frame_buffer-bytes_processed);
373     decoder_state->bytes_in_frame_buffer -= bytes_processed;
374 }
375 
376 static void btstack_sbc_decoder_process_msbc_data(btstack_sbc_decoder_state_t * state, int packet_status_flag, const uint8_t * buffer, int size){
377     bludroid_decoder_state_t * decoder_state = (bludroid_decoder_state_t*)state->decoder_state;
378     int input_bytes_to_process = size;
379     const unsigned int MSBC_FRAME_SIZE = 60;
380 
381     while (input_bytes_to_process > 0){
382 
383         // Use PLC to insert missing frames (after first sync found)
384         btstack_sbc_decoder_insert_missing_frames(state);
385         // fill buffer with new data
386         int bytes_missing_for_complete_msbc_frame = MSBC_FRAME_SIZE - decoder_state->bytes_in_frame_buffer;
387         int bytes_to_append = btstack_min(input_bytes_to_process, bytes_missing_for_complete_msbc_frame);
388         if (bytes_to_append) {
389             append_received_sbc_data(decoder_state, buffer, bytes_to_append);
390             buffer += bytes_to_append;
391             input_bytes_to_process -= bytes_to_append;
392         }
393         // complete frame in  buffer?
394         if (decoder_state->bytes_in_frame_buffer < MSBC_FRAME_SIZE) break;
395 
396         uint16_t bytes_in_frame_buffer_before_decoding = decoder_state->bytes_in_frame_buffer;
397         uint16_t bytes_processed = 0;
398         const OI_BYTE *frame_data = decoder_state->frame_buffer;
399 
400         // testing only - corrupt frame periodically
401         btstack_sbc_decoder_bluedroid_simulate_error(frame_data);
402 
403         // assert frame looks like this: 01 x8 AD [rest of frame 56 bytes] 00
404         int h2_syncword = 0;
405         int h2_sync_pos = find_h2_sync(frame_data, decoder_state->bytes_in_frame_buffer, &h2_syncword);
406         if (h2_sync_pos < 0){
407             // no sync found, discard all but last 2 bytes
408             bytes_processed = decoder_state->bytes_in_frame_buffer - 2;
409             btstack_sbc_decoder_drop_processed_bytes(decoder_state, bytes_processed);
410             // don't try PLC without at least a single good frame
411             if (decoder_state->first_good_frame_found){
412                 decoder_state->msbc_bad_bytes += bytes_processed;
413             }
414             continue;
415         }
416 
417         decoder_state->h2_sequence_nr = h2_syncword;
418 
419         // drop data before it
420         bytes_processed = h2_sync_pos - 2;
421         if (bytes_processed > 0){
422             memmove(decoder_state->frame_buffer, decoder_state->frame_buffer + bytes_processed, decoder_state->bytes_in_frame_buffer-bytes_processed);
423             decoder_state->bytes_in_frame_buffer -= bytes_processed;
424             // don't try PLC without at least a single good frame
425             if (decoder_state->first_good_frame_found){
426                 decoder_state->msbc_bad_bytes += bytes_processed;
427             }
428             continue;
429         }
430 
431         int bad_frame = 0;
432         int zero_seq_found = find_sequence_of_zeros(frame_data, decoder_state->bytes_in_frame_buffer, 20);
433 
434         // after first valid frame, zero sequences count as bad frames
435         if (decoder_state->first_good_frame_found){
436             bad_frame = zero_seq_found || packet_status_flag;
437         }
438 
439         if (bad_frame){
440             // stats
441             if (zero_seq_found){
442                 state->zero_frames_nr++;
443             } else {
444                 state->bad_frames_nr++;
445             }
446 #ifdef LOG_FRAME_STATUS
447             if (zero_seq_found){
448                 printf("%d : ZERO FRAME\n", decoder_state->h2_sequence_nr);
449             } else {
450                 printf("%d : BAD FRAME\n", decoder_state->h2_sequence_nr);
451             }
452 #endif
453             // retry after dropping 3 byte sync
454             bytes_processed = 3;
455             btstack_sbc_decoder_drop_processed_bytes(decoder_state, bytes_processed);
456             decoder_state->msbc_bad_bytes += bytes_processed;
457             // log_info("Trace bad frame");
458             continue;
459         }
460 
461         //ready to decode frame
462         OI_STATUS status = OI_CODEC_SBC_DecodeFrame(&(decoder_state->decoder_context),
463                                             &frame_data,
464                                             &(decoder_state->bytes_in_frame_buffer),
465                                             decoder_state->pcm_plc_data,
466                                             &(decoder_state->pcm_bytes));
467 
468         bytes_processed = bytes_in_frame_buffer_before_decoding - decoder_state->bytes_in_frame_buffer;
469         // log_info("Trace decode status %u, processed %u (bad bytes %u), bytes in buffer %u", (int) status, bytes_processed, decoder_state->msbc_bad_bytes, decoder_state->bytes_in_frame_buffer);
470 
471         switch(status){
472             case 0:
473                 // synced
474                 decoder_state->first_good_frame_found = 1;
475 
476                 // get rid of padding byte, not processed by SBC decoder
477                 decoder_state->bytes_in_frame_buffer = 0;
478 
479                 // restart counting bad bytes
480                 decoder_state->msbc_bad_bytes = 0;
481 
482                 // feed good frame into PLC history
483                 btstack_sbc_plc_good_frame(&state->plc_state, decoder_state->pcm_plc_data, decoder_state->pcm_data);
484 
485                 // deliver PCM data
486                 state->handle_pcm_data(decoder_state->pcm_data,
487                                     btstack_sbc_decoder_num_samples_per_frame(state),
488                                     btstack_sbc_decoder_num_channels(state),
489                                     btstack_sbc_decoder_sample_rate(state), state->context);
490 
491                 // stats
492                 state->good_frames_nr++;
493                 continue;
494 
495             case OI_CODEC_SBC_CHECKSUM_MISMATCH:
496                 // The next frame is somehow corrupt.
497                 log_debug("OI_CODEC_SBC_CHECKSUM_MISMATCH");
498                 // Did the codec consume any bytes?
499                 if (bytes_processed > 0){
500                     // Good. Nothing to do.
501                 } else {
502                     // Skip the bogus frame by skipping the header.
503                     bytes_processed = 1;
504                 }
505                 break;
506 
507             case OI_STATUS_INVALID_PARAMETERS:
508                 // This caused by corrupt frames.
509                 // The codec apparently does not recover from this.
510                 // Re-initialize the codec.
511                 log_info("SBC decode: invalid parameters: resetting codec");
512                 if (OI_CODEC_mSBC_DecoderReset(&(bd_decoder_state.decoder_context), bd_decoder_state.decoder_data, sizeof(bd_decoder_state.decoder_data)) != OI_STATUS_SUCCESS){
513                     log_info("SBC decode: resetting codec failed");
514                 }
515                 break;
516             default:
517                 log_info("Frame decode error: %d", status);
518                 break;
519         }
520 
521         // on success, while loop was restarted, so all processed bytes have been "bad"
522         decoder_state->msbc_bad_bytes += bytes_processed;
523 
524         // drop processed bytes from frame buffer
525         btstack_sbc_decoder_drop_processed_bytes(decoder_state, bytes_processed);
526     }
527 }
528 
529 void btstack_sbc_decoder_process_data(btstack_sbc_decoder_state_t * state, int packet_status_flag, const uint8_t * buffer, int size){
530     if (state->mode == SBC_MODE_mSBC){
531         btstack_sbc_decoder_process_msbc_data(state, packet_status_flag, buffer, size);
532     } else {
533         btstack_sbc_decoder_process_sbc_data(state, buffer, size);
534     }
535 }
536