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 MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define BTSTACK_FILE__ "audio_duplex.c" 39 40 /* EXAMPLE_START(audio_duplex): Audio Driver - Forward Audio from Source to Sink 41 * 42 */ 43 44 #include "btstack.h" 45 #include <stdio.h> 46 47 // uncomment to test start/stop of loopback / audio driver 48 // #define TEST_START_STOP_INTERVAL 5000 49 50 // change to 1 for mono input and 2 for stereo input 51 #define NUM_INPUT_CHANNELS 1 52 53 #define BYTES_PER_SAMPLE (NUM_INPUT_CHANNELS * 2) 54 55 #ifdef TEST_START_STOP_INTERVAL 56 static void stop_loopback(btstack_timer_source_t * ts); 57 #endif 58 59 static btstack_timer_source_t start_stop_timer; 60 61 // samplerate 62 const uint32_t samplerate = 16000; 63 64 // ring buffer for audio 65 #define BUFFER_SAMPLES 1024 66 static uint16_t audio_buffer_storage[BUFFER_SAMPLES]; 67 static btstack_ring_buffer_t audio_buffer; 68 69 // transfer buffer 70 #define TRANSFER_BUFFER_LEN 128 71 static int16_t transfer_buffer[TRANSFER_BUFFER_LEN]; 72 73 // playback starts after audio_buffer is half full 74 static int playback_started; 75 76 // sample couners 77 static int count_recording; 78 static int count_playback; 79 80 static void audio_recording(const int16_t * pcm_buffer, uint16_t num_samples_to_write){ 81 count_recording += num_samples_to_write; 82 int err = btstack_ring_buffer_write(&audio_buffer, (uint8_t *) pcm_buffer, num_samples_to_write * BYTES_PER_SAMPLE); 83 if (err){ 84 printf("Failed to store %u samples\n", num_samples_to_write); 85 } 86 } 87 88 static void audio_playback(int16_t * pcm_buffer, uint16_t num_samples_to_write){ 89 int num_samples_in_buffer = btstack_ring_buffer_bytes_available(&audio_buffer) / BYTES_PER_SAMPLE; 90 if (playback_started == 0){ 91 if ( num_samples_in_buffer < (BUFFER_SAMPLES / 2)) return; 92 playback_started = 1; 93 } 94 count_playback += num_samples_to_write; 95 while (num_samples_to_write){ 96 num_samples_in_buffer = btstack_ring_buffer_bytes_available(&audio_buffer) / BYTES_PER_SAMPLE; 97 int num_samples_ready = btstack_min(num_samples_in_buffer, num_samples_to_write); 98 // limit by transfer_buffer 99 int num_samples_from_buffer = btstack_min(num_samples_ready, TRANSFER_BUFFER_LEN); 100 if (!num_samples_from_buffer) break; 101 uint32_t bytes_read; 102 btstack_ring_buffer_read(&audio_buffer, (uint8_t *) transfer_buffer, num_samples_from_buffer * BYTES_PER_SAMPLE, &bytes_read); 103 #if (NUM_INPUT_CHANNELS == 1) 104 // duplicate samples for stereo output 105 int i; 106 for (i=0; i < num_samples_from_buffer;i++) { 107 *pcm_buffer++ = transfer_buffer[i]; 108 *pcm_buffer++ = transfer_buffer[i]; 109 num_samples_to_write--; 110 } 111 #endif 112 #if (NUM_INPUT_CHANNELS == 2) 113 // copy samples 114 int i; 115 int j = 0; 116 for (i=0; i < num_samples_from_buffer;i++) { 117 *pcm_buffer++ = transfer_buffer[j++]; 118 *pcm_buffer++ = transfer_buffer[j++]; 119 num_samples_to_write--; 120 } 121 #endif 122 } 123 124 // warn about underrun 125 if (num_samples_to_write){ 126 printf("Buffer underrun - recording %u, playback %u - delta %d!\n", count_recording, count_playback, count_recording - count_playback); 127 } 128 129 // fill rest with silence 130 while (num_samples_to_write){ 131 *pcm_buffer++ = 0; 132 *pcm_buffer++ = 0; 133 num_samples_to_write--; 134 } 135 } 136 137 static void start_loopback(btstack_timer_source_t * ts){ 138 const btstack_audio_sink_t * audio_sink = btstack_audio_sink_get_instance(); 139 const btstack_audio_source_t * audio_source = btstack_audio_source_get_instance(); 140 141 // prepare audio buffer 142 btstack_ring_buffer_init(&audio_buffer, (uint8_t*) &audio_buffer_storage[0], sizeof(audio_buffer_storage)); 143 144 // setup audio: mono input -> stereo output 145 audio_sink->init(2, samplerate, &audio_playback); 146 audio_source->init(NUM_INPUT_CHANNELS, samplerate, &audio_recording); 147 148 // start duplex 149 audio_sink->start_stream(); 150 audio_source->start_stream(); 151 152 printf("Start Audio Loopback\n"); 153 154 #ifdef TEST_START_STOP_INTERVAL 155 // schedule stop 156 btstack_run_loop_set_timer_handler(ts, &stop_loopback); 157 btstack_run_loop_set_timer(ts, TEST_START_STOP_INTERVAL); 158 btstack_run_loop_add_timer(ts); 159 #else 160 UNUSED(ts); 161 #endif 162 } 163 164 #ifdef TEST_START_STOP_INTERVAL 165 static void stop_loopback(btstack_timer_source_t * ts){ 166 const btstack_audio_sink_t * audio_sink = btstack_audio_sink_get_instance(); 167 const btstack_audio_source_t * audio_source = btstack_audio_source_get_instance(); 168 169 // stop streams 170 audio_sink->stop_stream(); 171 audio_source->stop_stream(); 172 173 // close audio 174 audio_sink->close(); 175 audio_source->close(); 176 177 playback_started = 0; 178 179 printf("Stop Audio Loopback\n"); 180 181 // schedule stop 182 btstack_run_loop_set_timer_handler(ts, &start_loopback); 183 btstack_run_loop_set_timer(ts, TEST_START_STOP_INTERVAL); 184 btstack_run_loop_add_timer(ts); 185 } 186 #endif 187 188 int btstack_main(int argc, const char * argv[]); 189 int btstack_main(int argc, const char * argv[]){ 190 (void)argc; 191 (void)argv; 192 193 // check audio interface 194 const btstack_audio_sink_t * audio_sink = btstack_audio_sink_get_instance(); 195 if (!audio_sink){ 196 printf("BTstack Audio Sink not setup\n"); 197 return 10; 198 } 199 200 const btstack_audio_source_t * audio_source = btstack_audio_source_get_instance(); 201 if (!audio_source){ 202 printf("BTstack Audio Source not setup\n"); 203 return 10; 204 } 205 206 start_loopback(&start_stop_timer); 207 208 return 0; 209 } 210 211 /* EXAMPLE_END */