video-play-reneg.c

Video input stream using pw_stream, with format renegotiation.

/* PipeWire */
/* SPDX-FileCopyrightText: Copyright © 2020 Wim Taymans */
/* SPDX-License-Identifier: MIT */
 
/*
 [title]
 Video input stream using \ref pw_stream "pw_stream", with format renegotiation.
 [title]
 */
 
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
 
#include <spa/utils/result.h>
#include <spa/param/video/format-utils.h>
#include <spa/param/props.h>
#include <spa/debug/format.h>
 
#include <pipewire/pipewire.h>
 
#define WIDTH   640
#define HEIGHT  480
 
#define MAX_BUFFERS     64
 
#include "sdl.h"
 
struct pixel {
        float r, g, b, a;
};
 
struct data {
        const char *path;
 
        SDL_Renderer *renderer;
        SDL_Window *window;
        SDL_Texture *texture;
        SDL_Texture *cursor;
 
        struct pw_main_loop *loop;
        struct spa_source *timer;
 
        struct pw_stream *stream;
        struct spa_hook stream_listener;
 
        struct spa_video_info format;
        int32_t stride;
        struct spa_rectangle size;
 
        int counter;
};
 
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_stream_dequeue_buffer(stream);
 *
 *  .. do stuff with buffer ...
 *
 *  pw_stream_queue_buffer(stream, b);
 */
static void
on_process(void *_data)
{
        struct data *data = _data;
        struct pw_stream *stream = data->stream;
        struct pw_buffer *b;
        struct spa_buffer *buf;
        void *sdata, *ddata;
        int sstride, dstride, ostride;
        uint32_t i;
        uint8_t *src, *dst;
 
        b = NULL;
        /* dequeue and queue old buffers, use the last available
         * buffer */
        while (true) {
                struct pw_buffer *t;
                if ((t = pw_stream_dequeue_buffer(stream)) == NULL)
                        break;
                if (b)
                        pw_stream_queue_buffer(stream, b);
                b = t;
        }
        if (b == NULL) {
                pw_log_warn("out of buffers: %m");
                return;
        }
 
        buf = b->buffer;
 
        pw_log_info("new buffer %p", buf);
 
        handle_events(data);
 
        if ((sdata = buf->datas[0].data) == NULL)
                goto done;
 
        if (SDL_LockTexture(data->texture, NULL, &ddata, &dstride) < 0) {
                fprintf(stderr, "Couldn't lock texture: %s\n", 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->size.height;
        ostride = SPA_MIN(sstride, dstride);
 
        src = sdata;
        dst = ddata;
 
        for (i = 0; i < data->size.height; i++) {
                memcpy(dst, src, ostride);
                src += sstride;
                dst += dstride;
        }
        SDL_UnlockTexture(data->texture);
 
        SDL_RenderClear(data->renderer);
        /* now render the video */
        SDL_RenderCopy(data->renderer, data->texture, NULL, NULL);
        SDL_RenderPresent(data->renderer);
 
      done:
        pw_stream_queue_buffer(stream, b);
}
 
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;
        fprintf(stderr, "stream state: \"%s\"\n", pw_stream_state_as_string(state));
        switch (state) {
        case PW_STREAM_STATE_UNCONNECTED:
                pw_main_loop_quit(data->loop);
                break;
        case PW_STREAM_STATE_PAUSED:
                pw_loop_update_timer(pw_main_loop_get_loop(data->loop),
                                data->timer, NULL, NULL, false);
                break;
        case PW_STREAM_STATE_STREAMING:
        {
                struct timespec timeout, interval;
 
                timeout.tv_sec = 1;
                timeout.tv_nsec = 0;
                interval.tv_sec = 1;
                interval.tv_nsec = 0;
 
                pw_loop_update_timer(pw_main_loop_get_loop(data->loop),
                                data->timer, &timeout, &interval, false);
                break;
        }
        default:
                break;
        }
}
 
/* Be notified when the stream param changes. We're only looking at the
 * format changes.
 *
 * We are now supposed to call pw_stream_finish_format() 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_finish_format() 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[1];
        Uint32 sdl_format;
        void *d;
 
        /* NULL means to clear the format */
        if (param == NULL || id != SPA_PARAM_Format)
                return;
 
        fprintf(stderr, "got format:\n");
        spa_debug_format(2, NULL, param);
 
        if (spa_format_parse(param, &data->format.media_type, &data->format.media_subtype) < 0)
                return;
 
        if (data->format.media_type != SPA_MEDIA_TYPE_video ||
            data->format.media_subtype != SPA_MEDIA_SUBTYPE_raw)
                return;
 
        /* call a helper function to parse the format for us. */
        spa_format_video_raw_parse(param, &data->format.info.raw);
        sdl_format = id_to_sdl_format(data->format.info.raw.format);
        data->size = data->format.info.raw.size;
 
        if (sdl_format == SDL_PIXELFORMAT_UNKNOWN) {
                pw_stream_set_error(stream, -EINVAL, "unknown pixel format");
                return;
        }
        if (data->size.width == 0 || data->size.height == 0) {
                pw_stream_set_error(stream, -EINVAL, "invalid size");
                return;
        }
 
        data->texture = SDL_CreateTexture(data->renderer,
                                          sdl_format,
                                          SDL_TEXTUREACCESS_STREAMING,
                                          data->size.width,
                                          data->size.height);
        SDL_LockTexture(data->texture, NULL, &d, &data->stride);
        SDL_UnlockTexture(data->texture);
 
        /* a SPA_TYPE_OBJECT_ParamBuffers object defines the acceptable size,
         * number, stride etc of the buffers */
        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->size.height),
                SPA_PARAM_BUFFERS_stride,  SPA_POD_Int(data->stride),
                SPA_PARAM_BUFFERS_dataType, SPA_POD_CHOICE_FLAGS_Int((1<<SPA_DATA_MemPtr)));
 
        /* we are done */
        pw_stream_update_params(stream, params, 1);
}
 
/* these are the stream events we listen for */
static const struct pw_stream_events stream_events = {
        PW_VERSION_STREAM_EVENTS,
        .state_changed = on_stream_state_changed,
        .param_changed = on_stream_param_changed,
        .process = on_process,
};
 
static int build_format(struct data *data, struct spa_pod_builder *b, const struct spa_pod **params)
{
        SDL_RendererInfo info;
 
        SDL_GetRendererInfo(data->renderer, &info);
        params[0] = sdl_build_formats(&info, b);
 
        fprintf(stderr, "supported SDL formats:\n");
        spa_debug_format(2, NULL, params[0]);
 
        return 1;
}
 
static int reneg_format(struct data *data)
{
        uint8_t buffer[1024];
        struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));
        const struct spa_pod *params[2];
        int32_t width, height;
 
        if (data->format.info.raw.format == 0)
                return -EBUSY;
 
        width = data->counter & 1 ? 320 : 640;
        height = data->counter & 1 ? 240 : 480;
 
        fprintf(stderr, "renegotiate to %dx%d:\n", width, height);
        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(data->format.info.raw.format),
                SPA_FORMAT_VIDEO_size,      SPA_POD_Rectangle(&SPA_RECTANGLE(width, height)),
                SPA_FORMAT_VIDEO_framerate, SPA_POD_Fraction(&data->format.info.raw.framerate));
 
        pw_stream_update_params(data->stream, params, 1);
 
        data->counter++;
        return 0;
}
 
static int reneg_buffers(struct data *data)
{
        uint8_t buffer[1024];
        struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));
        const struct spa_pod *params[2];
 
        fprintf(stderr, "renegotiate buffers\n");
        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->size.height),
                SPA_PARAM_BUFFERS_stride,  SPA_POD_Int(data->stride));
 
        pw_stream_update_params(data->stream, params, 1);
 
        data->counter++;
        return 0;
}
 
static void on_timeout(void *userdata, uint64_t expirations)
{
        struct data *data = userdata;
        if (1)
                reneg_format(data);
        else
                reneg_buffers(data);
}
 
static void do_quit(void *userdata, int signal_number)
{
        struct data *data = userdata;
        pw_main_loop_quit(data->loop);
}
 
int main(int argc, char *argv[])
{
        struct data data = { 0, };
        const struct spa_pod *params[2];
        uint8_t buffer[1024];
        struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));
        struct pw_properties *props;
        int res, n_params;
 
        pw_init(&argc, &argv);
 
        /* create a main loop */
        data.loop = pw_main_loop_new(NULL);
 
        pw_loop_add_signal(pw_main_loop_get_loop(data.loop), SIGINT, do_quit, &data);
        pw_loop_add_signal(pw_main_loop_get_loop(data.loop), SIGTERM, do_quit, &data);
 
        /* create a simple stream, the simple stream manages to core and remote
         * objects for you if you don't need to deal with them
         *
         * If you plan to autoconnect your stream, 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 stream state. The most important event
         * you need to listen to is the process event where you need to consume
         * the data provided to you.
         */
        props = pw_properties_new(PW_KEY_MEDIA_TYPE, "Video",
                        PW_KEY_MEDIA_CATEGORY, "Capture",
                        PW_KEY_MEDIA_ROLE, "Camera",
                        NULL),
        data.path = argc > 1 ? argv[1] : NULL;
        if (data.path)
                /* Set stream target if given on command line */
                pw_properties_set(props, PW_KEY_TARGET_OBJECT, data.path);
 
        data.stream = pw_stream_new_simple(
                        pw_main_loop_get_loop(data.loop),
                        "video-play-reneg",
                        props,
                        &stream_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;
        }
 
        /* build the extra parameters to connect with. To connect, we can provide
         * a list of supported formats.  We use a builder that writes the param
         * object to the stack. */
        n_params = build_format(&data, &b, params);
 
        /* now connect the stream, we need a direction (input/output),
         * an optional target node to connect to, some flags and parameters
         */
        if ((res = pw_stream_connect(data.stream,
                          PW_DIRECTION_INPUT,
                          PW_ID_ANY,
                          PW_STREAM_FLAG_AUTOCONNECT |  /* try to automatically connect this stream */
                          PW_STREAM_FLAG_MAP_BUFFERS,   /* mmap the buffer data for us */
                          params, n_params))            /* extra parameters, see above */ < 0) {
                fprintf(stderr, "can't connect: %s\n", spa_strerror(res));
                return -1;
        }
 
        data.timer = pw_loop_add_timer(pw_main_loop_get_loop(data.loop), on_timeout, &data);
 
        /* do things until we quit the mainloop */
        pw_main_loop_run(data.loop);
 
        pw_stream_destroy(data.stream);
        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);
        pw_deinit();
 
        return 0;
}