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Diffstat (limited to 'src/examples/audio-dsp-src.c')
| -rw-r--r-- | src/examples/audio-dsp-src.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/src/examples/audio-dsp-src.c b/src/examples/audio-dsp-src.c new file mode 100644 index 0000000..d7bf523 --- /dev/null +++ b/src/examples/audio-dsp-src.c @@ -0,0 +1,165 @@ +/* PipeWire + * + * Copyright © 2020 Wim Taymans + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + */ + +/* + [title] + Audio source using \ref pw_filter "pw_filter" + [title] + */ + +#include <stdio.h> +#include <errno.h> +#include <math.h> +#include <signal.h> + +#include <pipewire/pipewire.h> +#include <pipewire/filter.h> + +#define M_PI_M2 ( M_PI + M_PI ) + +#define DEFAULT_RATE 44100 +#define DEFAULT_FREQ 440 +#define DEFAULT_VOLUME 0.7 + +struct data; + +struct port { + struct data *data; + double accumulator; +}; + +struct data { + struct pw_main_loop *loop; + struct pw_filter *filter; + struct port *out_port; +}; + +/* our data processing function is in general: + * + * struct pw_buffer *b; + * out = pw_filter_dequeue_buffer(filter, out_port); + * + * .. generate data in the buffer ... + * + * pw_filter_queue_buffer(filter, out_port, out); + * + * For DSP ports, there is a shortcut to directly dequeue, get + * the data and requeue the buffer with pw_filter_get_dsp_buffer(). + */ +static void on_process(void *userdata, struct spa_io_position *position) +{ + struct data *data = userdata; + float *out; + struct port *out_port = data->out_port; + uint32_t i, n_samples = position->clock.duration; + + pw_log_trace("do process %d", n_samples); + + out = pw_filter_get_dsp_buffer(out_port, n_samples); + if (out == NULL) + return; + + for (i = 0; i < n_samples; i++) { + out_port->accumulator += M_PI_M2 * DEFAULT_FREQ / DEFAULT_RATE; + if (out_port->accumulator >= M_PI_M2) + out_port->accumulator -= M_PI_M2; + + *out++ = sin(out_port->accumulator) * DEFAULT_VOLUME; + } +} + +static const struct pw_filter_events filter_events = { + PW_VERSION_FILTER_EVENTS, + .process = on_process, +}; + +static void do_quit(void *userdata, int signal_number) +{ + struct data *data = userdata; + pw_main_loop_quit(data->loop); +} + +int main(int argc, char *argv[]) +{ + struct data data = { 0, }; + + pw_init(&argc, &argv); + + /* make a main loop. If you already have another main loop, you can add + * the fd of this pipewire mainloop to it. */ + data.loop = pw_main_loop_new(NULL); + + pw_loop_add_signal(pw_main_loop_get_loop(data.loop), SIGINT, do_quit, &data); + pw_loop_add_signal(pw_main_loop_get_loop(data.loop), SIGTERM, do_quit, &data); + + /* Create a simple filter, the simple filter manages the core and remote + * objects for you if you don't need to deal with them. + * + * Pass your events and a user_data pointer as the last arguments. This + * will inform you about the filter state. The most important event + * you need to listen to is the process event where you need to process + * the data. + */ + data.filter = pw_filter_new_simple( + pw_main_loop_get_loop(data.loop), + "audio-dsp-src", + pw_properties_new( + PW_KEY_MEDIA_TYPE, "Audio", + PW_KEY_MEDIA_CATEGORY, "Source", + PW_KEY_MEDIA_ROLE, "DSP", + PW_KEY_MEDIA_CLASS, "Stream/Output/Audio", + PW_KEY_NODE_AUTOCONNECT, "true", + NULL), + &filter_events, + &data); + + /* make an audio DSP output port */ + data.out_port = pw_filter_add_port(data.filter, + PW_DIRECTION_OUTPUT, + PW_FILTER_PORT_FLAG_MAP_BUFFERS, + sizeof(struct port), + pw_properties_new( + PW_KEY_FORMAT_DSP, "32 bit float mono audio", + PW_KEY_PORT_NAME, "output", + NULL), + NULL, 0); + + /* Now connect this filter. We ask that our process function is + * called in a realtime thread. */ + if (pw_filter_connect(data.filter, + PW_FILTER_FLAG_RT_PROCESS, + NULL, 0) < 0) { + fprintf(stderr, "can't connect\n"); + return -1; + } + + /* and wait while we let things run */ + pw_main_loop_run(data.loop); + + pw_filter_destroy(data.filter); + pw_main_loop_destroy(data.loop); + pw_deinit(); + + return 0; +} |