video-src-alloc.c

Allocating buffer memory and sending fds to the server.

/* PipeWire */
/* SPDX-FileCopyrightText: Copyright © 2018 Wim Taymans */
/* SPDX-License-Identifier: MIT */
 
/*
 [title]
 Allocating buffer memory and sending fds to the server.
 [title]
 */
 
#include "config.h"
 
#include <stdio.h>
#include <errno.h>
#include <signal.h>
#include <math.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
 
#include <spa/param/video/format-utils.h>
 
#include <pipewire/pipewire.h>
 
#define BPP             3
#define CURSOR_WIDTH    64
#define CURSOR_HEIGHT   64
#define CURSOR_BPP      4
 
#define MAX_BUFFERS     64
 
#define M_PI_M2 ( M_PI + M_PI )
 
struct data {
        struct pw_thread_loop *loop;
        struct spa_source *timer;
 
        struct pw_stream *stream;
        struct spa_hook stream_listener;
 
        struct spa_video_info_raw format;
        int32_t stride;
 
        int counter;
        uint32_t seq;
 
        double crop;
        double accumulator;
};
 
static void draw_elipse(uint32_t *dst, int width, int height, uint32_t color)
{
        int i, j, r1, r2, r12, r22, r122;
 
        r1 = width/2;
        r12 = r1 * r1;
        r2 = height/2;
        r22 = r2 * r2;
        r122 = r12 * r22;
 
        for (i = -r2; i < r2; i++) {
                for (j = -r1; j < r1; j++) {
                        dst[(i + r2)*width+(j+r1)] =
                                (i * i * r12 + j * j * r22 <= r122) ? color : 0x00000000;
                }
        }
}
 
/* called when we should push a new buffer in the queue */
static void on_process(void *userdata)
{
        struct data *data = userdata;
        struct pw_buffer *b;
        struct spa_buffer *buf;
        uint32_t i, j;
        uint8_t *p;
        struct spa_meta *m;
        struct spa_meta_header *h;
        struct spa_meta_region *mc;
        struct spa_meta_cursor *mcs;
 
        if ((b = pw_stream_dequeue_buffer(data->stream)) == NULL) {
                pw_log_warn("out of buffers: %m");
                return;
        }
 
        buf = b->buffer;
        if ((p = buf->datas[0].data) == NULL)
                return;
 
        if ((h = spa_buffer_find_meta_data(buf, SPA_META_Header, sizeof(*h)))) {
#if 0
                struct timespec now;
                clock_gettime(CLOCK_MONOTONIC, &now);
                h->pts = SPA_TIMESPEC_TO_NSEC(&now);
#else
                h->pts = -1;
#endif
                h->flags = 0;
                h->seq = data->seq++;
                h->dts_offset = 0;
        }
        if ((m = spa_buffer_find_meta(buf, SPA_META_VideoDamage))) {
                struct spa_meta_region *r = spa_meta_first(m);
 
                if (spa_meta_check(r, m)) {
                        r->region.position = SPA_POINT(0,0);
                        r->region.size = data->format.size;
                        r++;
                }
                if (spa_meta_check(r, m))
                        r->region = SPA_REGION(0,0,0,0);
        }
        if ((mc = spa_buffer_find_meta_data(buf, SPA_META_VideoCrop, sizeof(*mc)))) {
                data->crop = (sin(data->accumulator) + 1.0) * 32.0;
                mc->region.position.x = data->crop;
                mc->region.position.y = data->crop;
                mc->region.size.width = data->format.size.width - data->crop*2;
                mc->region.size.height = data->format.size.height - data->crop*2;
        }
        if ((mcs = spa_buffer_find_meta_data(buf, SPA_META_Cursor, sizeof(*mcs)))) {
                struct spa_meta_bitmap *mb;
                uint32_t *bitmap, color;
 
                mcs->id = 1;
                mcs->position.x = (sin(data->accumulator) + 1.0) * 160.0 + 80;
                mcs->position.y = (cos(data->accumulator) + 1.0) * 100.0 + 50;
                mcs->hotspot.x = 0;
                mcs->hotspot.y = 0;
                mcs->bitmap_offset = sizeof(struct spa_meta_cursor);
 
                mb = SPA_PTROFF(mcs, mcs->bitmap_offset, struct spa_meta_bitmap);
                mb->format = SPA_VIDEO_FORMAT_ARGB;
                mb->size.width = CURSOR_WIDTH;
                mb->size.height = CURSOR_HEIGHT;
                mb->stride = CURSOR_WIDTH * CURSOR_BPP;
                mb->offset = sizeof(struct spa_meta_bitmap);
 
                bitmap = SPA_PTROFF(mb, mb->offset, uint32_t);
                color = (cos(data->accumulator) + 1.0) * (1 << 23);
                color |= 0xff000000;
 
                draw_elipse(bitmap, mb->size.width, mb->size.height, color);
        }
 
        for (i = 0; i < data->format.size.height; i++) {
                for (j = 0; j < data->format.size.width * BPP; j++) {
                        p[j] = data->counter + j * i;
                }
                p += data->stride;
                data->counter += 13;
        }
 
        data->accumulator += M_PI_M2 / 50.0;
        if (data->accumulator >= M_PI_M2)
                data->accumulator -= M_PI_M2;
 
        buf->datas[0].chunk->offset = 0;
        buf->datas[0].chunk->size = data->format.size.height * data->stride;
        buf->datas[0].chunk->stride = data->stride;
 
        pw_stream_queue_buffer(data->stream, b);
}
 
/* trigger the graph when we are a driver */
static void on_timeout(void *userdata, uint64_t expirations)
{
        struct data *data = userdata;
        pw_log_trace("timeout");
        pw_stream_trigger_process(data->stream);
}
 
/* when the stream is STREAMING, start the timer at 40ms intervals
 * to produce and push a frame. In other states we PAUSE the timer. */
static void on_stream_state_changed(void *_data, enum pw_stream_state old, enum pw_stream_state state,
                                    const char *error)
{
        struct data *data = _data;
 
        printf("stream state: \"%s\"\n", pw_stream_state_as_string(state));
 
        switch (state) {
        case PW_STREAM_STATE_PAUSED:
                printf("node id: %d\n", pw_stream_get_node_id(data->stream));
                pw_loop_update_timer(pw_thread_loop_get_loop(data->loop),
                                data->timer, NULL, NULL, false);
                break;
        case PW_STREAM_STATE_STREAMING:
        {
                struct timespec timeout, interval;
 
                timeout.tv_sec = 0;
                timeout.tv_nsec = 1;
                interval.tv_sec = 0;
                interval.tv_nsec = 40 * SPA_NSEC_PER_MSEC;
 
                if (pw_stream_is_driving(data->stream))
                        pw_loop_update_timer(pw_thread_loop_get_loop(data->loop),
                                        data->timer, &timeout, &interval, false);
                break;
        }
        default:
                break;
        }
}
 
/* we set the PW_STREAM_FLAG_ALLOC_BUFFERS flag when connecting so we need
 * to provide buffer memory.  */
static void on_stream_add_buffer(void *_data, struct pw_buffer *buffer)
{
        struct data *data = _data;
        struct spa_buffer *buf = buffer->buffer;
        struct spa_data *d;
#ifdef HAVE_MEMFD_CREATE
        unsigned int seals;
#endif
 
        pw_log_info("add buffer %p", buffer);
        d = buf->datas;
 
        if ((d[0].type & (1<<SPA_DATA_MemFd)) == 0) {
                pw_log_error("unsupported data type %08x", d[0].type);
                return;
        }
 
        /* create the memfd on the buffer, set the type and flags */
        d[0].type = SPA_DATA_MemFd;
        d[0].flags = SPA_DATA_FLAG_READWRITE;
#ifdef HAVE_MEMFD_CREATE
        d[0].fd = memfd_create("video-src-memfd", MFD_CLOEXEC | MFD_ALLOW_SEALING);
#else
        d[0].fd = -1;
#endif
        if (d[0].fd == -1) {
                pw_log_error("can't create memfd: %m");
                return;
        }
        d[0].mapoffset = 0;
        d[0].maxsize = data->stride * data->format.size.height;
 
        /* truncate to the right size before we set seals */
        if (ftruncate(d[0].fd, d[0].maxsize) < 0) {
                pw_log_error("can't truncate to %d: %m", d[0].maxsize);
                return;
        }
#ifdef HAVE_MEMFD_CREATE
        /* not enforced yet but server might require SEAL_SHRINK later */
        seals = F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL;
        if (fcntl(d[0].fd, F_ADD_SEALS, seals) == -1) {
                pw_log_warn("Failed to add seals: %m");
        }
#endif
 
        /* now mmap so we can write to it in the process function above */
        d[0].data = mmap(NULL, d[0].maxsize, PROT_READ|PROT_WRITE,
                        MAP_SHARED, d[0].fd, d[0].mapoffset);
        if (d[0].data == MAP_FAILED) {
                pw_log_error("can't mmap memory: %m");
                return;
        }
}
 
/* close the memfd we set on the buffers here */
static void on_stream_remove_buffer(void *_data, struct pw_buffer *buffer)
{
        struct spa_buffer *buf = buffer->buffer;
        struct spa_data *d;
 
        d = buf->datas;
        pw_log_info("remove buffer %p", buffer);
 
        munmap(d[0].data, d[0].maxsize);
        close(d[0].fd);
}
 
/* Be notified when the stream param changes. We're only looking at the
 * format param.
 *
 * We are now supposed to call pw_stream_update_params() with success or
 * failure, depending on if we can support the format. Because we gave
 * a list of supported formats, this should be ok.
 *
 * As part of pw_stream_update_params() we can provide parameters that
 * will control the buffer memory allocation. This includes the metadata
 * that we would like on our buffer, the size, alignment, etc.
 */
static void
on_stream_param_changed(void *_data, uint32_t id, const struct spa_pod *param)
{
        struct data *data = _data;
        struct pw_stream *stream = data->stream;
        uint8_t params_buffer[1024];
        struct spa_pod_builder b = SPA_POD_BUILDER_INIT(params_buffer, sizeof(params_buffer));
        const struct spa_pod *params[5];
 
        if (param == NULL || id != SPA_PARAM_Format)
                return;
 
        spa_format_video_raw_parse(param, &data->format);
 
        data->stride = SPA_ROUND_UP_N(data->format.size.width * BPP, 4);
 
        params[0] = spa_pod_builder_add_object(&b,
                SPA_TYPE_OBJECT_ParamBuffers, SPA_PARAM_Buffers,
                SPA_PARAM_BUFFERS_buffers,  SPA_POD_CHOICE_RANGE_Int(8, 2, MAX_BUFFERS),
                SPA_PARAM_BUFFERS_blocks,   SPA_POD_Int(1),
                SPA_PARAM_BUFFERS_size,     SPA_POD_Int(data->stride * data->format.size.height),
                SPA_PARAM_BUFFERS_stride,   SPA_POD_Int(data->stride),
                SPA_PARAM_BUFFERS_dataType, SPA_POD_CHOICE_FLAGS_Int(1<<SPA_DATA_MemFd));
 
        params[1] = spa_pod_builder_add_object(&b,
                SPA_TYPE_OBJECT_ParamMeta, SPA_PARAM_Meta,
                SPA_PARAM_META_type, SPA_POD_Id(SPA_META_Header),
                SPA_PARAM_META_size, SPA_POD_Int(sizeof(struct spa_meta_header)));
 
        params[2] = spa_pod_builder_add_object(&b,
                SPA_TYPE_OBJECT_ParamMeta, SPA_PARAM_Meta,
                SPA_PARAM_META_type, SPA_POD_Id(SPA_META_VideoDamage),
                SPA_PARAM_META_size, SPA_POD_CHOICE_RANGE_Int(
                                        sizeof(struct spa_meta_region) * 16,
                                        sizeof(struct spa_meta_region) * 1,
                                        sizeof(struct spa_meta_region) * 16));
        params[3] = spa_pod_builder_add_object(&b,
                SPA_TYPE_OBJECT_ParamMeta, SPA_PARAM_Meta,
                SPA_PARAM_META_type, SPA_POD_Id(SPA_META_VideoCrop),
                SPA_PARAM_META_size, SPA_POD_Int(sizeof(struct spa_meta_region)));
#define CURSOR_META_SIZE(w,h)   (sizeof(struct spa_meta_cursor) + \
                                 sizeof(struct spa_meta_bitmap) + w * h * CURSOR_BPP)
        params[4] = spa_pod_builder_add_object(&b,
                SPA_TYPE_OBJECT_ParamMeta, SPA_PARAM_Meta,
                SPA_PARAM_META_type, SPA_POD_Id(SPA_META_Cursor),
                SPA_PARAM_META_size, SPA_POD_Int(
                        CURSOR_META_SIZE(CURSOR_WIDTH,CURSOR_HEIGHT)));
 
        pw_stream_update_params(stream, params, 5);
}
 
static const struct pw_stream_events stream_events = {
        PW_VERSION_STREAM_EVENTS,
        .process = on_process,
        .state_changed = on_stream_state_changed,
        .param_changed = on_stream_param_changed,
        .add_buffer = on_stream_add_buffer,
        .remove_buffer = on_stream_remove_buffer,
};
 
static void do_quit(void *userdata, int signal_number)
{
        struct data *data = userdata;
        pw_thread_loop_signal(data->loop, false);
}
 
int main(int argc, char *argv[])
{
        struct data data = { 0, };
        const struct spa_pod *params[1];
        uint8_t buffer[1024];
        struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));
 
        pw_init(&argc, &argv);
 
        /* create a thread loop and start it */
        data.loop = pw_thread_loop_new("video-src-alloc", NULL);
 
        /* take the lock around all PipeWire functions. In callbacks, the lock
         * is already taken for you but it's ok to lock again because the lock is
         * recursive */
        pw_thread_loop_lock(data.loop);
 
        /* install some handlers to exit nicely */
        pw_loop_add_signal(pw_thread_loop_get_loop(data.loop), SIGINT, do_quit, &data);
        pw_loop_add_signal(pw_thread_loop_get_loop(data.loop), SIGTERM, do_quit, &data);
 
        /* start after the signal handlers are set */
        pw_thread_loop_start(data.loop);
 
        /* create a simple stream, the simple stream manages the core
         * object for you if you don't want to deal with them.
         *
         * We're making a new video provider. We need to set the media-class
         * property.
         *
         * Pass your events and a user_data pointer as the last arguments. This
         * will inform you about the stream state. The most important event
         * you need to listen to is the process event where you need to provide
         * the data.
         */
        data.stream = pw_stream_new_simple(
                        pw_thread_loop_get_loop(data.loop),
                        "video-src-alloc",
                        pw_properties_new(
                                PW_KEY_MEDIA_CLASS, "Video/Source",
                                NULL),
                        &stream_events,
                        &data);
 
        /* make a timer to schedule our frames */
        data.timer = pw_loop_add_timer(pw_thread_loop_get_loop(data.loop), on_timeout, &data);
 
        /* build the extra parameter for the connection. Here we make an
         * EnumFormat parameter which lists the possible formats we can provide.
         * The server will select a format that matches and informs us about this
         * in the stream param_changed event.
         */
        params[0] = spa_pod_builder_add_object(&b,
                SPA_TYPE_OBJECT_Format, SPA_PARAM_EnumFormat,
                SPA_FORMAT_mediaType,       SPA_POD_Id(SPA_MEDIA_TYPE_video),
                SPA_FORMAT_mediaSubtype,    SPA_POD_Id(SPA_MEDIA_SUBTYPE_raw),
                SPA_FORMAT_VIDEO_format,    SPA_POD_Id(SPA_VIDEO_FORMAT_RGB),
                SPA_FORMAT_VIDEO_size,      SPA_POD_CHOICE_RANGE_Rectangle(
                                                &SPA_RECTANGLE(320, 240),
                                                &SPA_RECTANGLE(1, 1),
                                                &SPA_RECTANGLE(4096, 4096)),
                SPA_FORMAT_VIDEO_framerate, SPA_POD_Fraction(&SPA_FRACTION(25, 1)));
 
        /* now connect the stream, we need a direction (input/output),
         * an optional target node to connect to, some flags and parameters.
         *
         * Here we pass PW_STREAM_FLAG_ALLOC_BUFFERS. We should in the
         * add_buffer callback configure the buffer memory. This should be
         * fd backed memory (memfd, dma-buf, ...) that can be shared with
         * the server.  */
        pw_stream_connect(data.stream,
                          PW_DIRECTION_OUTPUT,
                          PW_ID_ANY,
                          PW_STREAM_FLAG_DRIVER |
                          PW_STREAM_FLAG_ALLOC_BUFFERS,
                          params, 1);
 
        /* unlock, run the loop and wait, this will trigger the callbacks */
        pw_thread_loop_wait(data.loop);
 
        /* unlock before stop */
        pw_thread_loop_unlock(data.loop);
        pw_thread_loop_stop(data.loop);
 
        pw_stream_destroy(data.stream);
 
        /* destroy after dependent objects are destroyed */
        pw_thread_loop_destroy(data.loop);
        pw_deinit();
 
        return 0;
}