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https://github.com/Ryujinx/libsoundio.git
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c381526205
This changes the semantics of the callbacks so that instead of a single `requested_frame_count` or `available_frame_count`, the callbacks get a minimum frame count and maximum frame count. The callback must write at least the minimum or get an underflow. The minimum will be 0 on ALSA, PulseAudio, and Dummy, and will equal the maximum on CoreAudio and JACK. This ensures optimal behavior regardless of buffer size.
143 lines
4.3 KiB
C
143 lines
4.3 KiB
C
/*
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* Copyright (c) 2015 Andrew Kelley
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*
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* This file is part of libsoundio, which is MIT licensed.
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* See http://opensource.org/licenses/MIT
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*/
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#include <soundio/soundio.h>
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#include <stdio.h>
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#include <stdarg.h>
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#include <stdlib.h>
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#include <string.h>
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#include <math.h>
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__attribute__ ((cold))
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__attribute__ ((noreturn))
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__attribute__ ((format (printf, 1, 2)))
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static void panic(const char *format, ...) {
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va_list ap;
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va_start(ap, format);
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vfprintf(stderr, format, ap);
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fprintf(stderr, "\n");
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va_end(ap);
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abort();
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}
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static int usage(char *exe) {
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fprintf(stderr, "Usage: %s [--dummy] [--alsa] [--pulseaudio] [--jack]\n", exe);
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return 1;
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}
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static const float PI = 3.1415926535f;
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static float seconds_offset = 0.0f;
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static void write_callback(struct SoundIoOutStream *outstream, int frame_count_min, int frame_count_max) {
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float float_sample_rate = outstream->sample_rate;
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float seconds_per_frame = 1.0f / float_sample_rate;
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struct SoundIoChannelArea *areas;
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int err;
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int frames_left = frame_count_max;
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for (;;) {
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int frame_count = frames_left;
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if ((err = soundio_outstream_begin_write(outstream, &areas, &frame_count)))
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panic("%s", soundio_strerror(err));
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if (!frame_count)
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break;
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const struct SoundIoChannelLayout *layout = &outstream->layout;
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float pitch = 440.0f;
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float radians_per_second = pitch * 2.0f * PI;
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for (int frame = 0; frame < frame_count; frame += 1) {
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float sample = sinf((seconds_offset + frame * seconds_per_frame) * radians_per_second);
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for (int channel = 0; channel < layout->channel_count; channel += 1) {
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float *ptr = (float*)(areas[channel].ptr + areas[channel].step * frame);
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*ptr = sample;
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}
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}
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seconds_offset += seconds_per_frame * frame_count;
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if ((err = soundio_outstream_end_write(outstream))) {
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if (err == SoundIoErrorUnderflow)
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return;
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panic("%s", soundio_strerror(err));
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}
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frames_left -= frame_count;
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if (frames_left <= 0)
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break;
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}
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}
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static void underflow_callback(struct SoundIoOutStream *outstream) {
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static int count = 0;
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fprintf(stderr, "underflow %d\n", count++);
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}
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int main(int argc, char **argv) {
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char *exe = argv[0];
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enum SoundIoBackend backend = SoundIoBackendNone;
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for (int i = 1; i < argc; i += 1) {
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char *arg = argv[i];
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if (strcmp("--dummy", arg) == 0) {
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backend = SoundIoBackendDummy;
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} else if (strcmp("--alsa", arg) == 0) {
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backend = SoundIoBackendAlsa;
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} else if (strcmp("--pulseaudio", arg) == 0) {
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backend = SoundIoBackendPulseAudio;
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} else if (strcmp("--jack", arg) == 0) {
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backend = SoundIoBackendJack;
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} else {
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return usage(exe);
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}
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}
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struct SoundIo *soundio = soundio_create();
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if (!soundio)
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panic("out of memory");
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int err = (backend == SoundIoBackendNone) ?
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soundio_connect(soundio) : soundio_connect_backend(soundio, backend);
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if (err)
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panic("error connecting: %s", soundio_strerror(err));
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soundio_flush_events(soundio);
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int default_out_device_index = soundio_default_output_device_index(soundio);
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if (default_out_device_index < 0)
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panic("no output device found");
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struct SoundIoDevice *device = soundio_get_output_device(soundio, default_out_device_index);
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if (!device)
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panic("out of memory");
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fprintf(stderr, "Output device: %s\n", device->name);
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struct SoundIoOutStream *outstream = soundio_outstream_create(device);
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outstream->format = SoundIoFormatFloat32NE;
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outstream->write_callback = write_callback;
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outstream->underflow_callback = underflow_callback;
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if ((err = soundio_outstream_open(outstream)))
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panic("unable to open device: %s", soundio_strerror(err));
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if (outstream->layout_error)
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fprintf(stderr, "unable to set channel layout: %s\n", soundio_strerror(outstream->layout_error));
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if ((err = soundio_outstream_start(outstream)))
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panic("unable to start device: %s", soundio_strerror(err));
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for (;;)
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soundio_wait_events(soundio);
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soundio_outstream_destroy(outstream);
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soundio_device_unref(device);
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soundio_destroy(soundio);
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return 0;
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}
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