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