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 /* 41 * Audio Duplex: forward audio from BTstack audio source to audio sink - test for audio interface 42 * 43 */ 44 45 #include "btstack.h" 46 47 48 // uncomment to test start/stop of loopback / audio driver 49 // #define TEST_START_STOP_INTERVAL 5000 50 51 // change to 1 for mono input and 2 for stereo input 52 #define NUM_INPUT_CHANNELS 1 53 54 #define BYTES_PER_SAMPLE (NUM_INPUT_CHANNELS * 2) 55 56 #ifdef TEST_START_STOP_INTERVAL 57 static void stop_loopback(btstack_timer_source_t * ts); 58 #endif 59 60 static btstack_timer_source_t start_stop_timer; 61 62 // samplerate 63 const uint32_t samplerate = 16000; 64 65 // ring buffer for audio 66 #define BUFFER_SAMPLES 1024 67 static uint16_t audio_buffer_storage[BUFFER_SAMPLES]; 68 static btstack_ring_buffer_t audio_buffer; 69 70 // transfer buffer 71 #define TRANSFER_BUFFER_LEN 128 72 static int16_t transfer_buffer[TRANSFER_BUFFER_LEN]; 73 74 // playback starts after audio_buffer is half full 75 static int playback_started; 76 77 // sample couners 78 static int count_recording; 79 static int count_playback; 80 81 static void audio_recording(const int16_t * pcm_buffer, uint16_t num_samples_to_write){ 82 count_recording += num_samples_to_write; 83 int err = btstack_ring_buffer_write(&audio_buffer, (uint8_t *) pcm_buffer, num_samples_to_write * BYTES_PER_SAMPLE); 84 if (err){ 85 printf("Failed to store %u samples\n", num_samples_to_write); 86 } 87 } 88 89 static void audio_playback(int16_t * pcm_buffer, uint16_t num_samples_to_write){ 90 int num_samples_in_buffer = btstack_ring_buffer_bytes_available(&audio_buffer) / BYTES_PER_SAMPLE; 91 if (playback_started == 0){ 92 if ( num_samples_in_buffer < (BUFFER_SAMPLES / 2)) return; 93 playback_started = 1; 94 } 95 count_playback += num_samples_to_write; 96 while (num_samples_to_write){ 97 num_samples_in_buffer = btstack_ring_buffer_bytes_available(&audio_buffer) / BYTES_PER_SAMPLE; 98 int num_samples_ready = btstack_min(num_samples_in_buffer, num_samples_to_write); 99 // limit by transfer_buffer 100 int num_samples_from_buffer = btstack_min(num_samples_ready, TRANSFER_BUFFER_LEN); 101 if (!num_samples_from_buffer) break; 102 uint32_t bytes_read; 103 btstack_ring_buffer_read(&audio_buffer, (uint8_t *) transfer_buffer, num_samples_from_buffer * BYTES_PER_SAMPLE, &bytes_read); 104 #if (NUM_INPUT_CHANNELS == 1) 105 // duplicate samples for stereo output 106 int i; 107 for (i=0; i < num_samples_from_buffer;i++) { 108 *pcm_buffer++ = transfer_buffer[i]; 109 *pcm_buffer++ = transfer_buffer[i]; 110 num_samples_to_write--; 111 } 112 #endif 113 #if (NUM_INPUT_CHANNELS == 2) 114 // copy samples 115 int i; 116 int j = 0; 117 for (i=0; i < num_samples_from_buffer;i++) { 118 *pcm_buffer++ = transfer_buffer[j++]; 119 *pcm_buffer++ = transfer_buffer[j++]; 120 num_samples_to_write--; 121 } 122 #endif 123 } 124 125 // warn about underrun 126 if (num_samples_to_write){ 127 printf("Buffer underrun - recording %u, playback %u - delta %d!\n", count_recording, count_playback, count_recording - count_playback); 128 } 129 130 // fill rest with silence 131 while (num_samples_to_write){ 132 *pcm_buffer++ = 0; 133 *pcm_buffer++ = 0; 134 num_samples_to_write--; 135 } 136 } 137 138 static void start_loopback(btstack_timer_source_t * ts){ 139 const btstack_audio_sink_t * audio_sink = btstack_audio_sink_get_instance(); 140 const btstack_audio_source_t * audio_source = btstack_audio_source_get_instance(); 141 142 // prepare audio buffer 143 btstack_ring_buffer_init(&audio_buffer, (uint8_t*) &audio_buffer_storage[0], sizeof(audio_buffer_storage)); 144 145 // setup audio: mono input -> stereo output 146 audio_sink->init(2, samplerate, &audio_playback); 147 audio_source->init(NUM_INPUT_CHANNELS, samplerate, &audio_recording); 148 149 // start duplex 150 audio_sink->start_stream(); 151 audio_source->start_stream(); 152 153 printf("Start Audio Loopback\n"); 154 155 #ifdef TEST_START_STOP_INTERVAL 156 // schedule stop 157 btstack_run_loop_set_timer_handler(ts, &stop_loopback); 158 btstack_run_loop_set_timer(ts, TEST_START_STOP_INTERVAL); 159 btstack_run_loop_add_timer(ts); 160 #else 161 UNUSED(ts); 162 #endif 163 } 164 165 #ifdef TEST_START_STOP_INTERVAL 166 static void stop_loopback(btstack_timer_source_t * ts){ 167 const btstack_audio_sink_t * audio_sink = btstack_audio_sink_get_instance(); 168 const btstack_audio_source_t * audio_source = btstack_audio_source_get_instance(); 169 170 // stop streams 171 audio_sink->stop_stream(); 172 audio_source->stop_stream(); 173 174 // close audio 175 audio_sink->close(); 176 audio_source->close(); 177 178 playback_started = 0; 179 180 printf("Stop Audio Loopback\n"); 181 182 // schedule stop 183 btstack_run_loop_set_timer_handler(ts, &start_loopback); 184 btstack_run_loop_set_timer(ts, TEST_START_STOP_INTERVAL); 185 btstack_run_loop_add_timer(ts); 186 } 187 #endif 188 189 int btstack_main(int argc, const char * argv[]); 190 int btstack_main(int argc, const char * argv[]){ 191 (void)argc; 192 (void)argv; 193 194 // check audio interface 195 const btstack_audio_sink_t * audio_sink = btstack_audio_sink_get_instance(); 196 if (!audio_sink){ 197 printf("BTstack Audio Sink not setup\n"); 198 return 10; 199 } 200 201 const btstack_audio_source_t * audio_source = btstack_audio_source_get_instance(); 202 if (!audio_source){ 203 printf("BTstack Audio Source not setup\n"); 204 return 10; 205 } 206 207 start_loopback(&start_stop_timer); 208 209 return 0; 210 } 211