local-v4l2.c

Example using libspa-v4l2, with only SPA

Example using libspa-v4l2, with only /builds/pipewire/pipewire/branch-1.2/builddir/doc/examples.dox

/* Spa */
/* SPDX-FileCopyrightText: Copyright © 2018 Wim Taymans */
/* SPDX-License-Identifier: MIT */
 
/*
 [title]
 Example using libspa-v4l2, with only \ref api_spa
 [title]
 */
 
#include "config.h"
 
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <dlfcn.h>
#include <poll.h>
#include <pthread.h>
#include <errno.h>
#include <sys/mman.h>
 
#include <SDL2/SDL.h>
 
#include <spa/support/plugin.h>
#include <spa/utils/names.h>
#include <spa/utils/result.h>
#include <spa/utils/string.h>
#include <spa/support/log-impl.h>
#include <spa/support/loop.h>
#include <spa/node/node.h>
#include <spa/node/io.h>
#include <spa/node/utils.h>
#include <spa/param/param.h>
#include <spa/param/props.h>
#include <spa/param/video/format-utils.h>
#include <spa/debug/pod.h>
 
static SPA_LOG_IMPL(default_log);
 
#define MAX_BUFFERS     8
 
struct buffer {
        struct spa_buffer buffer;
        struct spa_meta metas[1];
        struct spa_meta_header header;
        struct spa_data datas[1];
        struct spa_chunk chunks[1];
        SDL_Texture *texture;
};
 
struct data {
        const char *plugin_dir;
        struct spa_log *log;
        struct spa_system *system;
        struct spa_loop *loop;
        struct spa_loop_control *control;
 
        struct spa_support support[5];
        uint32_t n_support;
 
        struct spa_node *source;
        struct spa_hook listener;
        struct spa_io_buffers source_output[1];
 
        SDL_Renderer *renderer;
        SDL_Window *window;
        SDL_Texture *texture;
 
        bool use_buffer;
 
        bool running;
        pthread_t thread;
 
        struct spa_buffer *bp[MAX_BUFFERS];
        struct buffer buffers[MAX_BUFFERS];
        unsigned int n_buffers;
};
 
static int load_handle(struct data *data, struct spa_handle **handle, const char *lib, const char *name)
{
        int res;
        void *hnd;
        spa_handle_factory_enum_func_t enum_func;
        uint32_t i;
        char *path = NULL;
 
        if ((path = spa_aprintf("%s/%s", data->plugin_dir, lib)) == NULL) {
                return -ENOMEM;
        }
        if ((hnd = dlopen(path, RTLD_NOW)) == NULL) {
                printf("can't load %s: %s\n", path, dlerror());
                free(path);
                return -ENOENT;
        }
        free(path);
        if ((enum_func = dlsym(hnd, SPA_HANDLE_FACTORY_ENUM_FUNC_NAME)) == NULL) {
                printf("can't find enum function\n");
                return -ENOENT;
        }
 
        for (i = 0;;) {
                const struct spa_handle_factory *factory;
 
                if ((res = enum_func(&factory, &i)) <= 0) {
                        if (res != 0)
                                printf("can't enumerate factories: %s\n", spa_strerror(res));
                        break;
                }
                if (factory->version < 1)
                        continue;
                if (!spa_streq(factory->name, name))
                        continue;
 
                *handle = calloc(1, spa_handle_factory_get_size(factory, NULL));
                if ((res = spa_handle_factory_init(factory, *handle,
                                                NULL, data->support,
                                                data->n_support)) < 0) {
                        printf("can't make factory instance: %d\n", res);
                        return res;
                }
                return 0;
        }
        return -EBADF;
}
 
static int make_node(struct data *data, struct spa_node **node, const char *lib, const char *name)
{
        struct spa_handle *handle = NULL;
        void *iface;
        int res;
 
        if ((res = load_handle(data, &handle, lib, name)) < 0)
                return res;
 
        if ((res = spa_handle_get_interface(handle, SPA_TYPE_INTERFACE_Node, &iface)) < 0) {
                printf("can't get interface %d\n", res);
                return res;
        }
        *node = iface;
        return 0;
}
 
static int on_source_ready(void *_data, int status)
{
        struct data *data = _data;
        int res;
        struct buffer *b;
        void *sdata, *ddata;
        int sstride, dstride;
        int i;
        uint8_t *src, *dst;
        struct spa_data *datas;
        struct spa_io_buffers *io = &data->source_output[0];
 
        if (io->status != SPA_STATUS_HAVE_DATA ||
            io->buffer_id >= MAX_BUFFERS)
                return -EINVAL;
 
        b = &data->buffers[io->buffer_id];
        io->status = SPA_STATUS_NEED_DATA;
 
        datas = b->buffer.datas;
 
        if (b->texture) {
                SDL_Texture *texture = b->texture;
 
                SDL_UnlockTexture(texture);
 
                SDL_RenderClear(data->renderer);
                SDL_RenderCopy(data->renderer, texture, NULL, NULL);
                SDL_RenderPresent(data->renderer);
 
                if (SDL_LockTexture(texture, NULL, &sdata, &sstride) < 0) {
                        fprintf(stderr, "Couldn't lock texture: %s\n", SDL_GetError());
                        return -EIO;
                }
        } else {
                uint8_t *map;
 
                if (SDL_LockTexture(data->texture, NULL, &ddata, &dstride) < 0) {
                        fprintf(stderr, "Couldn't lock texture: %s\n", SDL_GetError());
                        return -EIO;
                }
                sdata = datas[0].data;
                if (datas[0].type == SPA_DATA_MemFd ||
                    datas[0].type == SPA_DATA_DmaBuf) {
                        map = mmap(NULL, datas[0].maxsize, PROT_READ,
                                   MAP_PRIVATE, datas[0].fd, datas[0].mapoffset);
                        if (map == MAP_FAILED)
                                return -errno;
                        sdata = map;
                } else if (datas[0].type == SPA_DATA_MemPtr) {
                        map = NULL;
                        sdata = datas[0].data;
                } else
                        return -EIO;
 
                sstride = datas[0].chunk->stride;
 
                for (i = 0; i < 240; i++) {
                        src = ((uint8_t *) sdata + i * sstride);
                        dst = ((uint8_t *) ddata + i * dstride);
                        memcpy(dst, src, SPA_MIN(sstride, dstride));
                }
                SDL_UnlockTexture(data->texture);
 
                SDL_RenderClear(data->renderer);
                SDL_RenderCopy(data->renderer, data->texture, NULL, NULL);
                SDL_RenderPresent(data->renderer);
 
                if (map)
                        munmap(map, datas[0].maxsize);
        }
 
        if ((res = spa_node_process(data->source)) < 0)
                printf("got process error %d\n", res);
 
        return 0;
}
 
static const struct spa_node_callbacks source_callbacks = {
        SPA_VERSION_NODE_CALLBACKS,
        .ready = on_source_ready,
};
 
static int make_nodes(struct data *data, const char *device)
{
        int res;
        struct spa_pod *props;
        struct spa_pod_builder b = { 0 };
        uint8_t buffer[256];
        uint32_t index;
 
        if ((res =
             make_node(data, &data->source,
                     "v4l2/libspa-v4l2.so",
                     SPA_NAME_API_V4L2_SOURCE)) < 0) {
                printf("can't create v4l2-source: %d\n", res);
                return res;
        }
 
        spa_node_set_callbacks(data->source, &source_callbacks, data);
 
        index = 0;
        spa_pod_builder_init(&b, buffer, sizeof(buffer));
        if ((res = spa_node_enum_params_sync(data->source, SPA_PARAM_Props,
                        &index, NULL, &props, &b)) == 1) {
                spa_debug_pod(0, NULL, props);
        }
 
        spa_pod_builder_init(&b, buffer, sizeof(buffer));
        props = spa_pod_builder_add_object(&b,
                SPA_TYPE_OBJECT_Props, 0,
                SPA_PROP_device, SPA_POD_String(device ? device : "/dev/video0"));
 
        if ((res = spa_node_set_param(data->source, SPA_PARAM_Props, 0, props)) < 0)
                printf("got set_props error %d\n", res);
 
        return res;
}
 
static int setup_buffers(struct data *data)
{
        int i;
 
        for (i = 0; i < MAX_BUFFERS; i++) {
                struct buffer *b = &data->buffers[i];
 
                data->bp[i] = &b->buffer;
 
                b->texture = NULL;
 
                b->buffer.metas = b->metas;
                b->buffer.n_metas = 1;
                b->buffer.datas = b->datas;
                b->buffer.n_datas = 1;
 
                b->header.flags = 0;
                b->header.seq = 0;
                b->header.pts = 0;
                b->header.dts_offset = 0;
                b->metas[0].type = SPA_META_Header;
                b->metas[0].data = &b->header;
                b->metas[0].size = sizeof(b->header);
 
                b->datas[0].type = 0;
                b->datas[0].flags = 0;
                b->datas[0].fd = -1;
                b->datas[0].mapoffset = 0;
                b->datas[0].maxsize = 0;
                b->datas[0].data = NULL;
                b->datas[0].chunk = &b->chunks[0];
                b->datas[0].chunk->offset = 0;
                b->datas[0].chunk->size = 0;
                b->datas[0].chunk->stride = 0;
        }
        data->n_buffers = MAX_BUFFERS;
        return 0;
}
 
static int sdl_alloc_buffers(struct data *data)
{
        int i;
 
        for (i = 0; i < MAX_BUFFERS; i++) {
                struct buffer *b = &data->buffers[i];
                SDL_Texture *texture;
                void *ptr;
                int stride;
 
                texture = SDL_CreateTexture(data->renderer,
                                            SDL_PIXELFORMAT_YUY2,
                                            SDL_TEXTUREACCESS_STREAMING, 320, 240);
                if (!texture) {
                        printf("can't create texture: %s\n", SDL_GetError());
                        return -ENOMEM;
                }
                if (SDL_LockTexture(texture, NULL, &ptr, &stride) < 0) {
                        fprintf(stderr, "Couldn't lock texture: %s\n", SDL_GetError());
                        return -EIO;
                }
                b->texture = texture;
 
                b->datas[0].type = SPA_DATA_MemPtr;
                b->datas[0].maxsize = stride * 240;
                b->datas[0].data = ptr;
                b->datas[0].chunk->offset = 0;
                b->datas[0].chunk->size = stride * 240;
                b->datas[0].chunk->stride = stride;
        }
        return 0;
}
 
static int negotiate_formats(struct data *data)
{
        int res;
        struct spa_pod *format;
        uint8_t buffer[256];
        struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));
 
        data->source_output[0] = SPA_IO_BUFFERS_INIT;
 
        if ((res =
             spa_node_port_set_io(data->source,
                                  SPA_DIRECTION_OUTPUT, 0,
                                  SPA_IO_Buffers,
                                  &data->source_output[0], sizeof(data->source_output[0]))) < 0)
                return res;
 
        format = spa_format_video_raw_build(&b, 0,
                        &SPA_VIDEO_INFO_RAW_INIT(
                                .format =  SPA_VIDEO_FORMAT_YUY2,
                                .size = SPA_RECTANGLE(320, 240),
                                .framerate = SPA_FRACTION(25,1)));
 
        if ((res = spa_node_port_set_param(data->source,
                                           SPA_DIRECTION_OUTPUT, 0,
                                           SPA_PARAM_Format, 0,
                                           format)) < 0)
                return res;
 
 
        setup_buffers(data);
 
        if (data->use_buffer) {
                if ((res = sdl_alloc_buffers(data)) < 0)
                        return res;
 
                if ((res = spa_node_port_use_buffers(data->source,
                                                SPA_DIRECTION_OUTPUT, 0, 0,
                                                data->bp, data->n_buffers)) < 0) {
                        printf("can't allocate buffers: %s\n", spa_strerror(res));
                        return -1;
                }
        } else {
                unsigned int n_buffers;
 
                data->texture = SDL_CreateTexture(data->renderer,
                                                  SDL_PIXELFORMAT_YUY2,
                                                  SDL_TEXTUREACCESS_STREAMING, 320, 240);
                if (!data->texture) {
                        printf("can't create texture: %s\n", SDL_GetError());
                        return -1;
                }
                n_buffers = MAX_BUFFERS;
                if ((res = spa_node_port_use_buffers(data->source,
                                                SPA_DIRECTION_OUTPUT, 0,
                                                SPA_NODE_BUFFERS_FLAG_ALLOC,
                                                data->bp, n_buffers)) < 0) {
                        printf("can't allocate buffers: %s\n", spa_strerror(res));
                        return -1;
                }
                data->n_buffers = n_buffers;
        }
        return 0;
}
 
static void *loop(void *user_data)
{
        struct data *data = user_data;
 
        printf("enter thread\n");
        spa_loop_control_enter(data->control);
 
        while (data->running) {
                spa_loop_control_iterate(data->control, -1);
        }
 
        printf("leave thread\n");
        spa_loop_control_leave(data->control);
        return NULL;
}
 
static void run_async_source(struct data *data)
{
        int res, err;
        struct spa_command cmd;
        SDL_Event event;
        bool running = true;
 
        cmd = SPA_NODE_COMMAND_INIT(SPA_NODE_COMMAND_Start);
        if ((res = spa_node_send_command(data->source, &cmd)) < 0)
                printf("got error %d\n", res);
 
        spa_loop_control_leave(data->control);
 
        data->running = true;
        if ((err = pthread_create(&data->thread, NULL, loop, data)) != 0) {
                printf("can't create thread: %d %s", err, strerror(err));
                data->running = false;
        }
 
        while (running && SDL_WaitEvent(&event)) {
                switch (event.type) {
                case SDL_QUIT:
                        running = false;
                        break;
                }
        }
 
        if (data->running) {
                data->running = false;
                pthread_join(data->thread, NULL);
        }
 
        spa_loop_control_enter(data->control);
 
        cmd = SPA_NODE_COMMAND_INIT(SPA_NODE_COMMAND_Pause);
        if ((res = spa_node_send_command(data->source, &cmd)) < 0)
                printf("got error %d\n", res);
}
 
int main(int argc, char *argv[])
{
        struct data data = { 0 };
        int res;
        const char *str;
        struct spa_handle *handle = NULL;
        void *iface;
 
        if ((str = getenv("SPA_PLUGIN_DIR")) == NULL)
                str = PLUGINDIR;
        data.plugin_dir = str;
 
        if ((res = load_handle(&data, &handle,
                                        "support/libspa-support.so",
                                        SPA_NAME_SUPPORT_SYSTEM)) < 0)
                return res;
 
        if ((res = spa_handle_get_interface(handle, SPA_TYPE_INTERFACE_System, &iface)) < 0) {
                printf("can't get System interface %d\n", res);
                return res;
        }
        data.system = iface;
        data.support[data.n_support++] = SPA_SUPPORT_INIT(SPA_TYPE_INTERFACE_System, data.system);
 
        if ((res = load_handle(&data, &handle,
                                        "support/libspa-support.so",
                                        SPA_NAME_SUPPORT_LOOP)) < 0)
                return res;
 
        if ((res = spa_handle_get_interface(handle, SPA_TYPE_INTERFACE_Loop, &iface)) < 0) {
                printf("can't get interface %d\n", res);
                return res;
        }
        data.loop = iface;
        if ((res = spa_handle_get_interface(handle, SPA_TYPE_INTERFACE_LoopControl, &iface)) < 0) {
                printf("can't get interface %d\n", res);
                return res;
        }
        data.control = iface;
 
        data.use_buffer = true;
 
        data.log = &default_log.log;
 
        if ((str = getenv("SPA_DEBUG")))
                data.log->level = atoi(str);
 
        data.support[data.n_support++] = SPA_SUPPORT_INIT(SPA_TYPE_INTERFACE_Log, data.log);
        data.support[data.n_support++] = SPA_SUPPORT_INIT(SPA_TYPE_INTERFACE_Loop, data.loop);
        data.support[data.n_support++] = SPA_SUPPORT_INIT(SPA_TYPE_INTERFACE_DataLoop, data.loop);
 
        if (SDL_Init(SDL_INIT_VIDEO) < 0) {
                printf("can't initialize SDL: %s\n", SDL_GetError());
                return -1;
        }
 
        if (SDL_CreateWindowAndRenderer
            (320, 240, SDL_WINDOW_RESIZABLE, &data.window, &data.renderer)) {
                printf("can't create window: %s\n", SDL_GetError());
                return -1;
        }
 
 
        if ((res = make_nodes(&data, argv[1])) < 0) {
                printf("can't make nodes: %d\n", res);
                return -1;
        }
        if ((res = negotiate_formats(&data)) < 0) {
                printf("can't negotiate nodes: %d\n", res);
                return -1;
        }
 
        spa_loop_control_enter(data.control);
        run_async_source(&data);
        spa_loop_control_leave(data.control);
 
        SDL_DestroyRenderer(data.renderer);
 
        return 0;
}