mirror of
https://gitlab.freedesktop.org/pipewire/pipewire.git
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271 lines
7.2 KiB
C
271 lines
7.2 KiB
C
/* PipeWire */
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/* SPDX-FileCopyrightText: Copyright © 2024 Wim Taymans */
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/* SPDX-License-Identifier: MIT */
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/*
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[title]
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Audio source using \ref pw_stream "pw_stream" and ringbuffer.
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This one uses a thread-loop and does a blocking push into a
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ringbuffer.
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[title]
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*/
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#include <stdio.h>
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#include <errno.h>
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#include <math.h>
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#include <signal.h>
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#include <spa/param/audio/format-utils.h>
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#include <spa/utils/ringbuffer.h>
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#include <pipewire/pipewire.h>
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#define M_PI_M2f (float)(M_PI+M_PI)
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#define DEFAULT_RATE 44100
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#define DEFAULT_CHANNELS 2
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#define DEFAULT_VOLUME 0.7f
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#define BUFFER_SIZE (16*1024)
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#define MIN_SIZE 256
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#define MAX_SIZE BUFFER_SIZE
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static float samples[BUFFER_SIZE * DEFAULT_CHANNELS];
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struct data {
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struct pw_thread_loop *thread_loop;
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struct pw_loop *loop;
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struct pw_stream *stream;
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int eventfd;
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bool running;
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float accumulator;
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struct spa_ringbuffer ring;
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float buffer[BUFFER_SIZE * DEFAULT_CHANNELS];
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};
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static void fill_f32(struct data *d, float *samples, int n_frames)
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{
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float val;
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int i, c;
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for (i = 0; i < n_frames; i++) {
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d->accumulator += M_PI_M2f * 440 / DEFAULT_RATE;
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if (d->accumulator >= M_PI_M2f)
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d->accumulator -= M_PI_M2f;
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val = sinf(d->accumulator) * DEFAULT_VOLUME;
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for (c = 0; c < DEFAULT_CHANNELS; c++)
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samples[i * DEFAULT_CHANNELS + c] = val;
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}
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}
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/* this can be called from any thread with a block of samples to write into
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* the ringbuffer. It will block until all data has been written */
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static void push_samples(void *userdata, float *samples, uint32_t n_samples)
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{
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struct data *data = userdata;
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int32_t filled;
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uint32_t index, avail, stride = sizeof(float) * DEFAULT_CHANNELS;
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uint64_t count;
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float *s = samples;
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while (n_samples > 0) {
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while (true) {
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filled = spa_ringbuffer_get_write_index(&data->ring, &index);
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/* we xrun, this can not happen because we never read more
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* than what there is in the ringbuffer and we never write more than
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* what is left */
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spa_assert(filled >= 0);
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spa_assert(filled <= BUFFER_SIZE);
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/* this is how much samples we can write */
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avail = BUFFER_SIZE - filled;
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if (avail > 0)
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break;
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/* no space.. block and wait for free space */
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spa_system_eventfd_read(data->loop->system, data->eventfd, &count);
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if (!data->running)
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return;
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}
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if (avail > n_samples)
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avail = n_samples;
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spa_ringbuffer_write_data(&data->ring,
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data->buffer, BUFFER_SIZE * stride,
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(index % BUFFER_SIZE) * stride,
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s, avail * stride);
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s += avail * DEFAULT_CHANNELS;
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n_samples -= avail;
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/* and advance the ringbuffer */
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spa_ringbuffer_write_update(&data->ring, index + avail);
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}
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}
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/* our data processing function is in general:
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*
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* struct pw_buffer *b;
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* b = pw_stream_dequeue_buffer(stream);
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*
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* .. generate stuff in the buffer ...
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* In this case we read samples from a ringbuffer. The ringbuffer is
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* filled up by another thread.
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*
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* pw_stream_queue_buffer(stream, b);
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*/
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static void on_process(void *userdata)
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{
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struct data *data = userdata;
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struct pw_buffer *b;
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struct spa_buffer *buf;
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uint8_t *p;
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uint32_t index, to_read, to_silence;
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int32_t avail, n_frames, stride;
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if ((b = pw_stream_dequeue_buffer(data->stream)) == NULL) {
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pw_log_warn("out of buffers: %m");
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return;
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}
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buf = b->buffer;
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if ((p = buf->datas[0].data) == NULL)
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return;
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/* the amount of space in the ringbuffer and the read index */
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avail = spa_ringbuffer_get_read_index(&data->ring, &index);
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stride = sizeof(float) * DEFAULT_CHANNELS;
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n_frames = buf->datas[0].maxsize / stride;
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if (b->requested)
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n_frames = SPA_MIN((int32_t)b->requested, n_frames);
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/* we can read if there is something available */
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to_read = avail > 0 ? SPA_MIN(avail, n_frames) : 0;
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/* and fill the remainder with silence */
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to_silence = n_frames - to_read;
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if (to_read > 0) {
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/* read data into the buffer */
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spa_ringbuffer_read_data(&data->ring,
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data->buffer, BUFFER_SIZE * stride,
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(index % BUFFER_SIZE) * stride,
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p, to_read * stride);
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/* update the read pointer */
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spa_ringbuffer_read_update(&data->ring, index + to_read);
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}
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if (to_silence > 0)
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/* set the rest of the buffer to silence */
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memset(SPA_PTROFF(p, to_read * stride, void), 0, to_silence * stride);
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buf->datas[0].chunk->offset = 0;
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buf->datas[0].chunk->stride = stride;
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buf->datas[0].chunk->size = n_frames * stride;
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pw_stream_queue_buffer(data->stream, b);
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/* signal the main thread to fill the ringbuffer, we can only do this, for
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* example when the available ringbuffer space falls below a certain
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* level. */
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spa_system_eventfd_write(data->loop->system, data->eventfd, 1);
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}
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static const struct pw_stream_events stream_events = {
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PW_VERSION_STREAM_EVENTS,
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.process = on_process,
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};
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static void do_quit(void *userdata, int signal_number)
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{
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struct data *data = userdata;
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data->running = false;
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}
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int main(int argc, char *argv[])
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{
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struct data data = { 0, };
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const struct spa_pod *params[1];
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uint8_t buffer[1024];
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struct pw_properties *props;
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struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));
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pw_init(&argc, &argv);
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data.thread_loop = pw_thread_loop_new("audio-src", NULL);
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data.loop = pw_thread_loop_get_loop(data.thread_loop);
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data.running = true;
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pw_thread_loop_lock(data.thread_loop);
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pw_loop_add_signal(data.loop, SIGINT, do_quit, &data);
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pw_loop_add_signal(data.loop, SIGTERM, do_quit, &data);
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spa_ringbuffer_init(&data.ring);
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if ((data.eventfd = spa_system_eventfd_create(data.loop->system, SPA_FD_CLOEXEC)) < 0)
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return data.eventfd;
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pw_thread_loop_start(data.thread_loop);
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props = pw_properties_new(PW_KEY_MEDIA_TYPE, "Audio",
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PW_KEY_MEDIA_CATEGORY, "Playback",
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PW_KEY_MEDIA_ROLE, "Music",
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NULL);
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if (argc > 1)
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/* Set stream target if given on command line */
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pw_properties_set(props, PW_KEY_TARGET_OBJECT, argv[1]);
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data.stream = pw_stream_new_simple(
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data.loop,
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"audio-src-ring",
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props,
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&stream_events,
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&data);
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/* Make one parameter with the supported formats. The SPA_PARAM_EnumFormat
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* id means that this is a format enumeration (of 1 value). */
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params[0] = spa_format_audio_raw_build(&b, SPA_PARAM_EnumFormat,
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&SPA_AUDIO_INFO_RAW_INIT(
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.format = SPA_AUDIO_FORMAT_F32,
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.channels = DEFAULT_CHANNELS,
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.rate = DEFAULT_RATE ));
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/* Now connect this stream. We ask that our process function is
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* called in a realtime thread. */
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pw_stream_connect(data.stream,
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PW_DIRECTION_OUTPUT,
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PW_ID_ANY,
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PW_STREAM_FLAG_AUTOCONNECT |
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PW_STREAM_FLAG_MAP_BUFFERS |
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PW_STREAM_FLAG_RT_PROCESS,
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params, 1);
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/* prefill the ringbuffer */
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fill_f32(&data, samples, BUFFER_SIZE);
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push_samples(&data, samples, BUFFER_SIZE);
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srand(time(NULL));
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pw_thread_loop_start(data.thread_loop);
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pw_thread_loop_unlock(data.thread_loop);
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while (data.running) {
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uint32_t size = rand() % ((MAX_SIZE - MIN_SIZE + 1) + MIN_SIZE);
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/* make new random sized block of samples and push */
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fill_f32(&data, samples, size);
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push_samples(&data, samples, size);
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}
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pw_thread_loop_lock(data.thread_loop);
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pw_stream_destroy(data.stream);
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pw_thread_loop_unlock(data.thread_loop);
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pw_thread_loop_destroy(data.thread_loop);
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close(data.eventfd);
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pw_deinit();
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return 0;
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}
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