video-dsp-play.c

Video input stream using pw_filter.

Video input stream using pw_filter.

/* PipeWire */
/* SPDX-FileCopyrightText: Copyright © 2019 Wim Taymans */
/* SPDX-License-Identifier: MIT */
 
/*
 [title]
 Video input stream using \ref pw_filter "pw_filter".
 [title]
 */
 
#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>
 
#include <spa/param/video/format-utils.h>
#include <spa/param/props.h>
#include <spa/debug/format.h>
 
#include <pipewire/pipewire.h>
#include <pipewire/filter.h>
 
#define WIDTH   640
#define HEIGHT  480
#define BPP    3
 
#define MAX_BUFFERS     64
 
#include "sdl.h"
 
struct pixel {
        float r, g, b, a;
};
 
struct data {
        const char *target;
 
        SDL_Renderer *renderer;
        SDL_Window *window;
        SDL_Texture *texture;
        SDL_Texture *cursor;
 
        struct pw_main_loop *loop;
 
        struct pw_filter *filter;
        struct spa_hook filter_listener;
 
        void *in_port;
 
        struct spa_io_position *position;
        struct spa_video_info_dsp format;
 
        int counter;
        SDL_Rect rect;
        SDL_Rect cursor_rect;
};
 
static void handle_events(struct data *data)
{
        SDL_Event event;
        while (SDL_PollEvent(&event)) {
                switch (event.type) {
                case SDL_QUIT:
                        pw_main_loop_quit(data->loop);
                        break;
                }
        }
}
 
/* our data processing function is in general:
 *
 *  struct pw_buffer *b;
 *  b = pw_filter_dequeue_buffer(port);
 *
 *  .. do stuff with buffer ...
 *
 *  pw_filter_queue_buffer(port, b);
 */
static void
on_process(void *_data, struct spa_io_position *position)
{
        struct data *data = _data;
        struct pw_buffer *b;
        struct spa_buffer *buf;
        void *sdata, *ddata;
        int sstride, dstride;
        uint32_t i, j;
        uint8_t *src, *dst;
 
        b = NULL;
        while (true) {
                struct pw_buffer *t;
                if ((t = pw_filter_dequeue_buffer(data->in_port)) == NULL)
                        break;
                if (b)
                        pw_filter_queue_buffer(data->in_port, b);
                b = t;
        }
        if (b == NULL) {
                pw_log_warn("out of buffers: %m");
                return;
        }
 
        buf = b->buffer;
 
        pw_log_trace("new buffer %p %dx%d", buf,
                        data->position->video.size.width, data->position->video.size.height);
 
        handle_events(data);
 
        if ((sdata = buf->datas[0].data) == NULL) {
                pw_log_error("no buffer data");
                goto done;
        }
 
        if (SDL_LockTexture(data->texture, NULL, &ddata, &dstride) < 0) {
                pw_log_error("Couldn't lock texture: %s", SDL_GetError());
                goto done;
        }
 
        /* copy video image in texture */
        sstride = buf->datas[0].chunk->stride;
        if (sstride == 0)
                sstride = buf->datas[0].chunk->size / data->position->video.size.height;
 
        src = sdata;
        dst = ddata;
 
        for (i = 0; i < data->position->video.size.height; i++) {
                struct pixel *p = (struct pixel *) src;
                for (j = 0; j < data->position->video.size.width; j++) {
                        dst[j * 4 + 0] = SPA_CLAMP((uint8_t)(p[j].r * 255.0f), 0, 255);
                        dst[j * 4 + 1] = SPA_CLAMP((uint8_t)(p[j].g * 255.0f), 0, 255);
                        dst[j * 4 + 2] = SPA_CLAMP((uint8_t)(p[j].b * 255.0f), 0, 255);
                        dst[j * 4 + 3] = SPA_CLAMP((uint8_t)(p[j].a * 255.0f), 0, 255);
                }
                src += sstride;
                dst += dstride;
        }
        SDL_UnlockTexture(data->texture);
 
        SDL_RenderClear(data->renderer);
        SDL_RenderCopy(data->renderer, data->texture, &data->rect, NULL);
        SDL_RenderPresent(data->renderer);
 
      done:
        pw_filter_queue_buffer(data->in_port, b);
}
 
static void on_filter_state_changed(void *_data, enum pw_filter_state old,
                                    enum pw_filter_state state, const char *error)
{
        struct data *data = _data;
        fprintf(stderr, "filter state: \"%s\"\n", pw_filter_state_as_string(state));
        switch (state) {
        case PW_FILTER_STATE_UNCONNECTED:
                pw_main_loop_quit(data->loop);
                break;
        default:
                break;
        }
}
 
static void
on_filter_io_changed(void *_data, void *port_data, uint32_t id, void *area, uint32_t size)
{
        struct data *data = _data;
 
        switch (id) {
        case SPA_IO_Position:
                data->position = area;
                break;
        }
}
 
static void
on_filter_param_changed(void *_data, void *port_data, uint32_t id, const struct spa_pod *param)
{
        struct data *data = _data;
        struct pw_filter *filter = data->filter;
 
        /* NULL means to clear the format */
        if (param == NULL || id != SPA_PARAM_Format)
                return;
 
        /* call a helper function to parse the format for us. */
        spa_format_video_dsp_parse(param, &data->format);
 
        if (data->format.format != SPA_VIDEO_FORMAT_RGBA_F32) {
                pw_filter_set_error(filter, -EINVAL, "unknown format");
                return;
        }
 
        data->texture = SDL_CreateTexture(data->renderer,
                                          SDL_PIXELFORMAT_RGBA32,
                                          SDL_TEXTUREACCESS_STREAMING,
                                          data->position->video.size.width,
                                          data->position->video.size.height);
        if (data->texture == NULL) {
                pw_filter_set_error(filter, -errno, "can't create texture");
                return;
        }
 
        data->rect.x = 0;
        data->rect.y = 0;
        data->rect.w = data->position->video.size.width;
        data->rect.h = data->position->video.size.height;
}
 
/* these are the filter events we listen for */
static const struct pw_filter_events filter_events = {
        PW_VERSION_FILTER_EVENTS,
        .state_changed = on_filter_state_changed,
        .io_changed = on_filter_io_changed,
        .param_changed = on_filter_param_changed,
        .process = on_process,
};
 
int main(int argc, char *argv[])
{
        struct data data = { 0, };
 
        pw_init(&argc, &argv);
 
        /* create a main loop */
        data.loop = pw_main_loop_new(NULL);
 
        data.target = argc > 1 ? argv[1] : NULL;
 
        /* create a simple filter, the simple filter manages to core and remote
         * objects for you if you don't need to deal with them
         *
         * If you plan to autoconnect your filter, you need to provide at least
         * media, category and role properties
         *
         * Pass your events and a user_data pointer as the last arguments. This
         * will inform you about the filter state. The most important event
         * you need to listen to is the process event where you need to consume
         * the data provided to you.
         */
        data.filter = pw_filter_new_simple(
                        pw_main_loop_get_loop(data.loop),
                        "video-dsp-play",
                        pw_properties_new(
                                PW_KEY_MEDIA_TYPE, "Video",
                                PW_KEY_MEDIA_CATEGORY, "Capture",
                                PW_KEY_MEDIA_ROLE, "DSP",
                                PW_KEY_NODE_AUTOCONNECT, data.target ? "true" : "false",
                                PW_KEY_TARGET_OBJECT, data.target,
                                PW_KEY_MEDIA_CLASS, "Stream/Input/Video",
                                NULL),
                        &filter_events,
                        &data);
 
 
        if (SDL_Init(SDL_INIT_VIDEO) < 0) {
                fprintf(stderr, "can't initialize SDL: %s\n", SDL_GetError());
                return -1;
        }
 
        if (SDL_CreateWindowAndRenderer
            (WIDTH, HEIGHT, SDL_WINDOW_RESIZABLE, &data.window, &data.renderer)) {
                fprintf(stderr, "can't create window: %s\n", SDL_GetError());
                return -1;
        }
 
        /* Make a new DSP port. This will automatically set up the right
         * parameters for the port */
        data.in_port = pw_filter_add_port(data.filter,
                        PW_DIRECTION_INPUT,
                        PW_FILTER_PORT_FLAG_MAP_BUFFERS,
                        0,
                        pw_properties_new(
                                PW_KEY_FORMAT_DSP, "32 bit float RGBA video",
                                PW_KEY_PORT_NAME, "input",
                                NULL),
                        NULL, 0);
 
        pw_filter_connect(data.filter,
                        0,              /* no flags */
                        NULL, 0);
 
        /* do things until we quit the mainloop */
        pw_main_loop_run(data.loop);
 
        pw_filter_destroy(data.filter);
        pw_main_loop_destroy(data.loop);
 
        SDL_DestroyTexture(data.texture);
        if (data.cursor)
                SDL_DestroyTexture(data.cursor);
        SDL_DestroyRenderer(data.renderer);
        SDL_DestroyWindow(data.window);
 
        return 0;
}