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__ "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 2048 66 static uint16_t audio_buffer_storage[BUFFER_SAMPLES * NUM_INPUT_CHANNELS]; 67 static btstack_ring_buffer_t audio_buffer; 68 69 // transfer buffer 70 #define TRANSFER_SAMPLES 128 71 static int16_t transfer_buffer[TRANSFER_SAMPLES * NUM_INPUT_CHANNELS]; 72 73 // playback starts after audio_buffer is half full 74 static bool 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 == false){ 91 if ( num_samples_in_buffer >= (BUFFER_SAMPLES / 2)){ 92 playback_started = true; 93 } 94 } 95 count_playback += num_samples_to_write; 96 97 if (playback_started){ 98 99 while (num_samples_to_write){ 100 101 num_samples_in_buffer = btstack_ring_buffer_bytes_available(&audio_buffer) / BYTES_PER_SAMPLE; 102 int num_samples_ready = btstack_min(num_samples_in_buffer, num_samples_to_write); 103 // limit by transfer_buffer 104 int num_samples_from_buffer = btstack_min(num_samples_ready, TRANSFER_SAMPLES); 105 if (!num_samples_from_buffer) break; 106 uint32_t bytes_read; 107 btstack_ring_buffer_read(&audio_buffer, (uint8_t *) transfer_buffer, num_samples_from_buffer * BYTES_PER_SAMPLE, &bytes_read); 108 109 #if (NUM_INPUT_CHANNELS == 1) 110 // duplicate samples for stereo output 111 int i; 112 for (i=0; i < num_samples_from_buffer;i++) { 113 *pcm_buffer++ = transfer_buffer[i]; 114 *pcm_buffer++ = transfer_buffer[i]; 115 num_samples_to_write--; 116 } 117 #endif 118 119 #if (NUM_INPUT_CHANNELS == 2) 120 // copy samples 121 int i; 122 int j = 0; 123 for (i=0; i < num_samples_from_buffer;i++) { 124 *pcm_buffer++ = transfer_buffer[j++]; 125 *pcm_buffer++ = transfer_buffer[j++]; 126 num_samples_to_write--; 127 } 128 #endif 129 130 } 131 132 // warn about underrun 133 if (num_samples_to_write){ 134 printf("Buffer underrun - recording %u, playback %u - delta %d!\n", count_recording, count_playback, count_recording - count_playback); 135 } 136 137 } 138 139 // fill rest with silence 140 memset(pcm_buffer, 0, num_samples_to_write * 4); 141 } 142 143 static void start_loopback(btstack_timer_source_t * ts){ 144 const btstack_audio_sink_t * audio_sink = btstack_audio_sink_get_instance(); 145 const btstack_audio_source_t * audio_source = btstack_audio_source_get_instance(); 146 147 // prepare audio buffer 148 btstack_ring_buffer_init(&audio_buffer, (uint8_t*) &audio_buffer_storage[0], sizeof(audio_buffer_storage)); 149 150 // setup audio: mono input -> stereo output 151 audio_sink->init(2, samplerate, &audio_playback); 152 audio_source->init(NUM_INPUT_CHANNELS, samplerate, &audio_recording); 153 154 // start duplex 155 audio_sink->start_stream(); 156 audio_source->start_stream(); 157 158 printf("Start Audio Loopback\n"); 159 160 #ifdef TEST_START_STOP_INTERVAL 161 // schedule stop 162 btstack_run_loop_set_timer_handler(ts, &stop_loopback); 163 btstack_run_loop_set_timer(ts, TEST_START_STOP_INTERVAL); 164 btstack_run_loop_add_timer(ts); 165 #else 166 UNUSED(ts); 167 #endif 168 } 169 170 #ifdef TEST_START_STOP_INTERVAL 171 static void stop_loopback(btstack_timer_source_t * ts){ 172 const btstack_audio_sink_t * audio_sink = btstack_audio_sink_get_instance(); 173 const btstack_audio_source_t * audio_source = btstack_audio_source_get_instance(); 174 175 // stop streams 176 audio_sink->stop_stream(); 177 audio_source->stop_stream(); 178 179 // close audio 180 audio_sink->close(); 181 audio_source->close(); 182 183 playback_started = false; 184 185 printf("Stop Audio Loopback\n"); 186 187 // schedule stop 188 btstack_run_loop_set_timer_handler(ts, &start_loopback); 189 btstack_run_loop_set_timer(ts, TEST_START_STOP_INTERVAL); 190 btstack_run_loop_add_timer(ts); 191 } 192 #endif 193 194 int btstack_main(int argc, const char * argv[]); 195 int btstack_main(int argc, const char * argv[]){ 196 (void)argc; 197 (void)argv; 198 199 // check audio interface 200 const btstack_audio_sink_t * audio_sink = btstack_audio_sink_get_instance(); 201 if (!audio_sink){ 202 printf("BTstack Audio Sink not setup\n"); 203 return 10; 204 } 205 206 const btstack_audio_source_t * audio_source = btstack_audio_source_get_instance(); 207 if (!audio_source){ 208 printf("BTstack Audio Source not setup\n"); 209 return 10; 210 } 211 212 start_loopback(&start_stop_timer); 213 214 return 0; 215 } 216 217 /* EXAMPLE_END */ 218