export-source.c

Exporting and implementing a video source SPA node, using Core API.

Exporting and implementing a video source SPA node, using /builds/pipewire/pipewire/branch-1.2/builddir/doc/examples.dox

/* PipeWire */
/* SPDX-FileCopyrightText: Copyright © 2018 Wim Taymans */
/* SPDX-License-Identifier: MIT */
 
/*
 [title]
 Exporting and implementing a video source SPA node, using \ref api_pw_core.
 [title]
 */
 
#include <errno.h>
#include <stdio.h>
#include <math.h>
#include <sys/mman.h>
 
#include <spa/utils/result.h>
#include <spa/param/audio/format-utils.h>
#include <spa/param/props.h>
#include <spa/node/io.h>
#include <spa/node/utils.h>
#include <spa/pod/filter.h>
#include <spa/debug/format.h>
 
#include <pipewire/pipewire.h>
 
#define M_PI_M2f (float)(M_PI + M_PI)
 
#define BUFFER_SAMPLES  128
#define MAX_BUFFERS     32
 
struct buffer {
        uint32_t id;
        struct spa_buffer *buffer;
        struct spa_list link;
        void *ptr;
        bool mapped;
};
 
struct data {
        const char *path;
 
        struct pw_main_loop *loop;
 
        struct pw_context *context;
 
        struct pw_core *core;
        struct spa_hook core_listener;
 
        uint64_t info_all;
        struct spa_port_info info;
        struct spa_dict_item items[1];
        struct spa_dict dict;
        struct spa_param_info params[5];
 
        struct spa_node impl_node;
        struct spa_hook_list hooks;
        struct spa_io_buffers *io;
        struct spa_io_control *io_notify;
        uint32_t io_notify_size;
 
        struct spa_audio_info_raw format;
 
        struct buffer buffers[MAX_BUFFERS];
        uint32_t n_buffers;
        struct spa_list empty;
 
        float accumulator;
        float volume_accum;
};
 
static void update_volume(struct data *data)
{
        struct spa_pod_builder b = { 0, };
        struct spa_pod_frame f[2];
 
        if (data->io_notify == NULL)
                return;
 
        spa_pod_builder_init(&b, data->io_notify, data->io_notify_size);
        spa_pod_builder_push_sequence(&b, &f[0], 0);
        spa_pod_builder_control(&b, 0, SPA_CONTROL_Properties);
        spa_pod_builder_push_object(&b, &f[1], SPA_TYPE_OBJECT_Props, 0);
        spa_pod_builder_prop(&b, SPA_PROP_volume, 0);
        spa_pod_builder_float(&b, (sinf(data->volume_accum) / 2.0f) + 0.5f);
        spa_pod_builder_pop(&b, &f[1]);
        spa_pod_builder_pop(&b, &f[0]);
 
        data->volume_accum += M_PI_M2f / 1000.0f;
        if (data->volume_accum >= M_PI_M2f)
                data->volume_accum -= M_PI_M2f;
}
 
static int impl_send_command(void *object, const struct spa_command *command)
{
        return 0;
}
 
static int impl_add_listener(void *object,
                struct spa_hook *listener,
                const struct spa_node_events *events,
                void *data)
{
        struct data *d = object;
        struct spa_hook_list save;
        uint64_t old;
 
        spa_hook_list_isolate(&d->hooks, &save, listener, events, data);
 
        old = d->info.change_mask;
        d->info.change_mask = d->info_all;
        spa_node_emit_port_info(&d->hooks, SPA_DIRECTION_OUTPUT, 0, &d->info);
        d->info.change_mask = old;
 
        spa_hook_list_join(&d->hooks, &save);
        return 0;
}
 
static int impl_set_callbacks(void *object,
                              const struct spa_node_callbacks *callbacks, void *data)
{
        return 0;
}
 
static int impl_set_io(void *object,
                        uint32_t id, void *data, size_t size)
{
        return 0;
}
 
static int impl_port_set_io(void *object, enum spa_direction direction, uint32_t port_id,
                            uint32_t id, void *data, size_t size)
{
        struct data *d = object;
 
        switch (id) {
        case SPA_IO_Buffers:
                d->io = data;
                break;
        case SPA_IO_Notify:
                d->io_notify = data;
                d->io_notify_size = size;
                break;
        default:
                return -ENOENT;
        }
        return 0;
}
 
static int impl_port_enum_params(void *object, int seq,
                                 enum spa_direction direction, uint32_t port_id,
                                 uint32_t id, uint32_t start, uint32_t num,
                                 const struct spa_pod *filter)
{
        struct data *d = object;
        struct spa_pod *param;
        struct spa_pod_builder b = { 0 };
        uint8_t buffer[1024];
        struct spa_result_node_params result;
        uint32_t count = 0;
 
        result.id = id;
        result.next = start;
      next:
        result.index = result.next++;
 
        spa_pod_builder_init(&b, buffer, sizeof(buffer));
 
        switch (id) {
        case SPA_PARAM_EnumFormat:
                if (result.index != 0)
                        return 0;
 
                param = spa_pod_builder_add_object(&b,
                        SPA_TYPE_OBJECT_Format, SPA_PARAM_EnumFormat,
                        SPA_FORMAT_mediaType,      SPA_POD_Id(SPA_MEDIA_TYPE_audio),
                        SPA_FORMAT_mediaSubtype,   SPA_POD_Id(SPA_MEDIA_SUBTYPE_raw),
                        SPA_FORMAT_AUDIO_format,   SPA_POD_CHOICE_ENUM_Id(5,
                                                        SPA_AUDIO_FORMAT_S16,
                                                        SPA_AUDIO_FORMAT_S16P,
                                                        SPA_AUDIO_FORMAT_S16,
                                                        SPA_AUDIO_FORMAT_F32P,
                                                        SPA_AUDIO_FORMAT_F32),
                        SPA_FORMAT_AUDIO_channels, SPA_POD_CHOICE_RANGE_Int(2, 1, INT32_MAX),
                        SPA_FORMAT_AUDIO_rate,     SPA_POD_CHOICE_RANGE_Int(44100, 1, INT32_MAX));
                break;
 
        case SPA_PARAM_Format:
                if (result.index != 0)
                        return 0;
                if (d->format.format == 0)
                        return 0;
                param = spa_format_audio_raw_build(&b, id, &d->format);
                break;
 
        case SPA_PARAM_Buffers:
                if (result.index > 0)
                        return 0;
 
                param = spa_pod_builder_add_object(&b,
                        SPA_TYPE_OBJECT_ParamBuffers, id,
                        SPA_PARAM_BUFFERS_buffers, SPA_POD_CHOICE_RANGE_Int(1, 1, 32),
                        SPA_PARAM_BUFFERS_blocks,  SPA_POD_Int(1),
                        SPA_PARAM_BUFFERS_size,    SPA_POD_CHOICE_RANGE_Int(
                                                        BUFFER_SAMPLES * sizeof(float), 32, INT32_MAX),
                        SPA_PARAM_BUFFERS_stride,  SPA_POD_Int(sizeof(float)));
                break;
 
        case SPA_PARAM_Meta:
                switch (result.index) {
                case 0:
                        param = spa_pod_builder_add_object(&b,
                                SPA_TYPE_OBJECT_ParamMeta, id,
                                SPA_PARAM_META_type, SPA_POD_Id(SPA_META_Header),
                                SPA_PARAM_META_size, SPA_POD_Int(sizeof(struct spa_meta_header)));
                        break;
                default:
                        return 0;
                }
                break;
        case SPA_PARAM_IO:
                switch (result.index) {
                case 0:
                        param = spa_pod_builder_add_object(&b,
                                SPA_TYPE_OBJECT_ParamIO, id,
                                SPA_PARAM_IO_id, SPA_POD_Id(SPA_IO_Buffers),
                                SPA_PARAM_IO_size, SPA_POD_Int(sizeof(struct spa_io_buffers)));
                        break;
                case 1:
                        param = spa_pod_builder_add_object(&b,
                                SPA_TYPE_OBJECT_ParamIO, id,
                                SPA_PARAM_IO_id, SPA_POD_Id(SPA_IO_Notify),
                                SPA_PARAM_IO_size, SPA_POD_Int(sizeof(struct spa_io_sequence) + 1024));
                        break;
                default:
                        return 0;
                }
                break;
        default:
                return -ENOENT;
        }
 
        if (spa_pod_filter(&b, &result.param, param, filter) < 0)
                goto next;
 
        spa_node_emit_result(&d->hooks, seq, 0, SPA_RESULT_TYPE_NODE_PARAMS, &result);
 
        if (++count != num)
                goto next;
 
        return 0;
}
 
static int port_set_format(void *object,
                           enum spa_direction direction, uint32_t port_id,
                           uint32_t flags, const struct spa_pod *format)
{
        struct data *d = object;
 
        if (format == NULL) {
                spa_zero(d->format);
        } else {
                spa_debug_format(0, NULL, format);
 
                if (spa_format_audio_raw_parse(format, &d->format) < 0)
                        return -EINVAL;
 
                if (d->format.format != SPA_AUDIO_FORMAT_S16 &&
                    d->format.format != SPA_AUDIO_FORMAT_F32)
                        return -EINVAL;
                if (d->format.rate == 0 ||
                    d->format.channels == 0 ||
                    d->format.channels > SPA_AUDIO_MAX_CHANNELS)
                        return -EINVAL;
        }
 
        d->info.change_mask = SPA_PORT_CHANGE_MASK_PARAMS;
        if (format) {
                d->params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_READWRITE);
                d->params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, SPA_PARAM_INFO_READ);
        } else {
                d->params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_WRITE);
                d->params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, 0);
        }
        spa_node_emit_port_info(&d->hooks, SPA_DIRECTION_OUTPUT, 0, &d->info);
 
        return 0;
}
 
static int impl_port_set_param(void *object,
                               enum spa_direction direction, uint32_t port_id,
                               uint32_t id, uint32_t flags,
                               const struct spa_pod *param)
{
        if (id == SPA_PARAM_Format) {
                return port_set_format(object, direction, port_id, flags, param);
        }
        else
                return -ENOENT;
}
 
static int impl_port_use_buffers(void *object,
                enum spa_direction direction, uint32_t port_id,
                uint32_t flags,
                struct spa_buffer **buffers, uint32_t n_buffers)
{
        struct data *d = object;
        uint32_t i;
 
        if (n_buffers > MAX_BUFFERS)
                return -ENOSPC;
 
        for (i = 0; i < n_buffers; i++) {
                struct buffer *b = &d->buffers[i];
                struct spa_data *datas = buffers[i]->datas;
 
                if (datas[0].data != NULL) {
                        b->ptr = datas[0].data;
                        b->mapped = false;
                }
                else if (datas[0].type == SPA_DATA_MemFd ||
                         datas[0].type == SPA_DATA_DmaBuf) {
                        b->ptr = mmap(NULL, datas[0].maxsize, PROT_WRITE,
                                      MAP_SHARED, datas[0].fd, datas[0].mapoffset);
                        if (b->ptr == MAP_FAILED) {
                                pw_log_error("failed to buffer mem");
                                return -errno;
 
                        }
                        b->mapped = true;
                }
                else {
                        pw_log_error("invalid buffer mem");
                        return -EINVAL;
                }
                b->id = i;
                b->buffer = buffers[i];
                pw_log_debug("got buffer %d size %d", i, datas[0].maxsize);
                spa_list_append(&d->empty, &b->link);
        }
        d->n_buffers = n_buffers;
        return 0;
}
 
static inline void reuse_buffer(struct data *d, uint32_t id)
{
        pw_log_trace("export-source %p: recycle buffer %d", d, id);
        spa_list_append(&d->empty, &d->buffers[id].link);
}
 
static int impl_port_reuse_buffer(void *object, uint32_t port_id, uint32_t buffer_id)
{
        struct data *d = object;
        reuse_buffer(d, buffer_id);
        return 0;
}
 
static void fill_f32(struct data *d, void *dest, int avail)
{
        float *dst = dest;
        int n_samples = avail / (sizeof(float) * d->format.channels);
        int i;
        uint32_t c;
 
        for (i = 0; i < n_samples; i++) {
                float val;
 
                d->accumulator += M_PI_M2f * 440 / d->format.rate;
                if (d->accumulator >= M_PI_M2f)
                        d->accumulator -= M_PI_M2f;
 
                val = sinf(d->accumulator);
 
                for (c = 0; c < d->format.channels; c++)
                        *dst++ = val;
        }
}
 
static void fill_s16(struct data *d, void *dest, int avail)
{
        int16_t *dst = dest;
        int n_samples = avail / (sizeof(int16_t) * d->format.channels);
        int i;
        uint32_t c;
 
        for (i = 0; i < n_samples; i++) {
                int16_t val;
 
                d->accumulator += M_PI_M2f * 440 / d->format.rate;
                if (d->accumulator >= M_PI_M2f)
                        d->accumulator -= M_PI_M2f;
 
                val = (int16_t) (sinf(d->accumulator) * 32767.0f);
 
                for (c = 0; c < d->format.channels; c++)
                        *dst++ = val;
        }
}
 
static int impl_node_process(void *object)
{
        struct data *d = object;
        struct buffer *b;
        int avail;
        struct spa_io_buffers *io = d->io;
        uint32_t maxsize, index = 0;
        uint32_t filled, offset;
        struct spa_data *od;
 
        if (io->buffer_id < d->n_buffers) {
                reuse_buffer(d, io->buffer_id);
                io->buffer_id = SPA_ID_INVALID;
        }
        if (spa_list_is_empty(&d->empty)) {
                pw_log_error("export-source %p: out of buffers", d);
                return -EPIPE;
        }
        b = spa_list_first(&d->empty, struct buffer, link);
        spa_list_remove(&b->link);
 
        od = b->buffer->datas;
 
        maxsize = od[0].maxsize;
 
        filled = 0;
        index = 0;
        avail = maxsize - filled;
        offset = index % maxsize;
 
        if (offset + avail > maxsize)
                avail = maxsize - offset;
 
        if (d->format.format == SPA_AUDIO_FORMAT_S16)
                fill_s16(d, SPA_PTROFF(b->ptr, offset, void), avail);
        else if (d->format.format == SPA_AUDIO_FORMAT_F32)
                fill_f32(d, SPA_PTROFF(b->ptr, offset, void), avail);
 
        od[0].chunk->offset = 0;
        od[0].chunk->size = avail;
        od[0].chunk->stride = 0;
 
        io->buffer_id = b->id;
        io->status = SPA_STATUS_HAVE_DATA;
 
        update_volume(d);
 
        return SPA_STATUS_HAVE_DATA;
}
 
static const struct spa_node_methods impl_node = {
        SPA_VERSION_NODE_METHODS,
        .add_listener = impl_add_listener,
        .set_callbacks = impl_set_callbacks,
        .set_io = impl_set_io,
        .send_command = impl_send_command,
        .port_set_io = impl_port_set_io,
        .port_enum_params = impl_port_enum_params,
        .port_set_param = impl_port_set_param,
        .port_use_buffers = impl_port_use_buffers,
        .port_reuse_buffer = impl_port_reuse_buffer,
        .process = impl_node_process,
};
 
static void make_node(struct data *data)
{
        struct pw_properties *props;
 
        props = pw_properties_new(PW_KEY_NODE_AUTOCONNECT, "true",
                                  PW_KEY_NODE_EXCLUSIVE, "true",
                                  PW_KEY_MEDIA_TYPE, "Audio",
                                  PW_KEY_MEDIA_CATEGORY, "Playback",
                                  PW_KEY_MEDIA_ROLE, "Music",
                                  NULL);
        if (data->path)
                pw_properties_set(props, PW_KEY_TARGET_OBJECT, data->path);
 
        data->impl_node.iface = SPA_INTERFACE_INIT(
                        SPA_TYPE_INTERFACE_Node,
                        SPA_VERSION_NODE,
                        &impl_node, data);
        pw_core_export(data->core, SPA_TYPE_INTERFACE_Node,
                        &props->dict, &data->impl_node, 0);
        pw_properties_free(props);
}
 
static void on_core_error(void *data, uint32_t id, int seq, int res, const char *message)
{
        struct data *d = data;
 
        pw_log_error("error id:%u seq:%d res:%d (%s): %s",
                        id, seq, res, spa_strerror(res), message);
 
        if (id == PW_ID_CORE)
                pw_main_loop_quit(d->loop);
}
 
static const struct pw_core_events core_events = {
        PW_VERSION_CORE_EVENTS,
        .error = on_core_error,
};
 
int main(int argc, char *argv[])
{
        struct data data = { 0, };
 
        pw_init(&argc, &argv);
 
        data.loop = pw_main_loop_new(NULL);
        data.context = pw_context_new(pw_main_loop_get_loop(data.loop), NULL, 0);
        data.path = argc > 1 ? argv[1] : NULL;
 
        data.info_all = SPA_PORT_CHANGE_MASK_FLAGS |
                SPA_PORT_CHANGE_MASK_PROPS |
                SPA_PORT_CHANGE_MASK_PARAMS;
        data.info = SPA_PORT_INFO_INIT();
        data.info.flags = 0;
        data.items[0] = SPA_DICT_ITEM_INIT(PW_KEY_FORMAT_DSP, "32 bit float mono audio");
        data.dict = SPA_DICT_INIT_ARRAY(data.items);
        data.info.props = &data.dict;
        data.params[0] = SPA_PARAM_INFO(SPA_PARAM_EnumFormat, SPA_PARAM_INFO_READ);
        data.params[1] = SPA_PARAM_INFO(SPA_PARAM_Meta, SPA_PARAM_INFO_READ);
        data.params[2] = SPA_PARAM_INFO(SPA_PARAM_IO, SPA_PARAM_INFO_READ);
        data.params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_WRITE);
        data.params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, 0);
        data.info.params = data.params;
        data.info.n_params = 5;
 
        spa_list_init(&data.empty);
        spa_hook_list_init(&data.hooks);
 
        if ((data.core = pw_context_connect(data.context, NULL, 0)) == NULL) {
                printf("can't connect: %m\n");
                return -1;
        }
 
        pw_core_add_listener(data.core, &data.core_listener, &core_events, &data);
 
        make_node(&data);
 
        pw_main_loop_run(data.loop);
 
        pw_context_destroy(data.context);
        pw_main_loop_destroy(data.loop);
 
        return 0;
}