video-play-fixate.c

Video input stream using pw_stream, with format fixation.

Video input stream using pw_stream, with format fixation.

/* PipeWire */
/* SPDX-FileCopyrightText: Copyright © 2020 Wim Taymans */
/* SPDX-License-Identifier: MIT */
 
/*
 [title]
 Video input stream using \ref pw_stream "pw_stream", with format fixation.
 [title]
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <libdrm/drm_fourcc.h>
#include <sys/mman.h>
#include <sys/sysmacros.h>
#include <assert.h>
 
#include <spa/utils/json.h>
#include <spa/utils/result.h>
#include <spa/param/dict-utils.h>
#include <spa/param/peer-utils.h>
#include <spa/param/video/format-utils.h>
#include <spa/param/props.h>
#include <spa/debug/format.h>
#include <spa/debug/pod.h>
 
#include <pipewire/pipewire.h>
#include <pipewire/capabilities.h>
 
#include "utils.h"
 
/* Comment out to test device ID negotation backward compatibility. */
#define SUPPORT_DEVICE_ID_NEGOTIATION 1
/* If defined, emulate failing to import DMA buffer. */
#define EMULATE_DMA_BUF_IMPORT_FAIL 1
 
#define WIDTH   640
#define HEIGHT  480
#define RATE    30
 
#define MAX_BUFFERS     64
#define MAX_MOD         8
#define MAX_PARAMS      16
#define MAX_DEVICE_IDS  16
 
#include "sdl.h"
 
struct pixel {
        float r, g, b, a;
};
 
struct pw_version {
  int major;
  int minor;
  int micro;
};
 
struct modifier_info {
        uint32_t spa_format;
        uint32_t n_modifiers;
        uint64_t modifiers[MAX_MOD];
};
 
struct {
        unsigned int major;
        unsigned int minor;
        struct modifier_info mod_info;
} devices[] = {
#if 1
        {
                .major = 100,
                .minor = 100,
                .mod_info = {
                        .spa_format = SPA_VIDEO_FORMAT_RGBA,
                        .modifiers = { DRM_FORMAT_MOD_LINEAR, DRM_FORMAT_MOD_INVALID },
                        .n_modifiers = 2,
                },
        },
#endif
#if 1
        {
                .major = 200,
                .minor = 200,
                .mod_info = {
                        .spa_format = SPA_VIDEO_FORMAT_RGBA,
                        .modifiers = {DRM_FORMAT_MOD_LINEAR, DRM_FORMAT_MOD_GENERIC_16_16_TILE},
                        .n_modifiers = 2,
                },
        },
#endif
};
 
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 *reneg;
 
        struct pw_stream *stream;
        struct spa_hook stream_listener;
 
        struct spa_video_info format;
        int32_t stride;
        struct spa_rectangle size;
 
        int counter;
 
        bool capabilities_known;
        bool device_negotiation_supported;
 
        dev_t device_ids[MAX_DEVICE_IDS];
        size_t n_device_ids;
 
        int used_device_index;
};
 
static int build_formats(struct data *data, struct spa_pod_builder *b, const struct spa_pod **params);
 
#ifdef EMULATE_DMA_BUF_IMPORT_FAIL
static struct pw_version parse_pw_version(const char* version) {
        struct pw_version pw_version;
        sscanf(version, "%d.%d.%d", &pw_version.major, &pw_version.minor,
                &pw_version.micro);
        return pw_version;
}
 
static bool has_pw_version(int major, int minor, int micro) {
        struct pw_version pw_version = parse_pw_version(pw_get_library_version());
        printf("PW Version: %d.%d.%d\n", pw_version.major, pw_version.minor,
                pw_version.micro);
        return major <= pw_version.major && minor <= pw_version.minor && micro <= pw_version.micro;
}
 
static void strip_modifier(struct data *data, uint32_t spa_format, uint64_t modifier)
{
        struct modifier_info *mod_info;
 
        assert(data->used_device_index >= 0);
 
        mod_info = &devices[data->used_device_index].mod_info;
 
        if (mod_info->spa_format != spa_format)
                return;
 
        uint32_t counter = 0;
        // Dropping of single modifiers is only supported on PipeWire 0.3.40 and newer.
        // On older PipeWire just dropping all modifiers might work on Versions newer then 0.3.33/35
        if (has_pw_version(0,3,40)) {
                printf("Dropping a single modifier from device %u:%u\n",
                        devices[data->used_device_index].major,
                        devices[data->used_device_index].minor);
                for (uint32_t i = 0; i < mod_info->n_modifiers; i++) {
                        if (mod_info->modifiers[i] == modifier)
                                continue;
                        mod_info->modifiers[counter++] = mod_info->modifiers[i];
                }
        } else {
                printf("Dropping all modifiers from device %u:%u\n",
                        devices[data->used_device_index].major,
                        devices[data->used_device_index].minor);
                counter = 0;
        }
        mod_info->n_modifiers = counter;
}
#endif /* EMULATE_DMA_BUF_IMPORT_FAIL */
 
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;
                }
        }
}
 
static struct spa_pod *build_format(struct data *data, struct spa_pod_builder *b,
        SDL_RendererInfo *info, enum spa_video_format format, int device_index)
{
        struct spa_pod_frame f[2];
        int i, c;
        uint64_t *modifiers;
        int modifier_count;
 
        if (device_index == -1) {
                modifiers = NULL;
                modifier_count = 0;
        } else {
                struct modifier_info *mod_info = &devices[device_index].mod_info;
 
                modifiers = mod_info->modifiers;
                modifier_count = mod_info->n_modifiers;
        }
 
        spa_pod_builder_push_object(b, &f[0], SPA_TYPE_OBJECT_Format, SPA_PARAM_EnumFormat);
        spa_pod_builder_add(b, SPA_FORMAT_mediaType, SPA_POD_Id(SPA_MEDIA_TYPE_video), 0);
        spa_pod_builder_add(b, SPA_FORMAT_mediaSubtype, SPA_POD_Id(SPA_MEDIA_SUBTYPE_raw), 0);
        /* device */
        if (data->device_negotiation_supported && device_index >= 0) {
                dev_t device_id = makedev(devices[device_index].major,
                        devices[device_index].minor);
 
                spa_pod_builder_prop(b, SPA_FORMAT_VIDEO_deviceId,
                        SPA_POD_PROP_FLAG_MANDATORY);
                spa_pod_builder_bytes(b, &device_id, sizeof device_id);
        }
        /* format */
        spa_pod_builder_add(b, SPA_FORMAT_VIDEO_format, SPA_POD_Id(format), 0);
        /* modifiers */
        if (modifier_count == 1 && modifiers[0] == DRM_FORMAT_MOD_INVALID) {
                // we only support implicit modifiers, use shortpath to skip fixation phase
                spa_pod_builder_prop(b, SPA_FORMAT_VIDEO_modifier, SPA_POD_PROP_FLAG_MANDATORY);
                spa_pod_builder_long(b, modifiers[0]);
        } else if (modifier_count > 0) {
                // build an enumeration of modifiers
                spa_pod_builder_prop(b, SPA_FORMAT_VIDEO_modifier, SPA_POD_PROP_FLAG_MANDATORY | SPA_POD_PROP_FLAG_DONT_FIXATE);
                spa_pod_builder_push_choice(b, &f[1], SPA_CHOICE_Enum, 0);
                // modifiers from the array
                for (i = 0, c = 0; i < modifier_count; i++) {
                        spa_pod_builder_long(b, modifiers[i]);
                        if (c++ == 0)
                                spa_pod_builder_long(b, modifiers[i]);
                }
                spa_pod_builder_pop(b, &f[1]);
        }
        spa_pod_builder_add(b, SPA_FORMAT_VIDEO_size,
                SPA_POD_CHOICE_RANGE_Rectangle(
                        &SPA_RECTANGLE(WIDTH, HEIGHT),
                        &SPA_RECTANGLE(1,1),
                        &SPA_RECTANGLE(info->max_texture_width,
                                       info->max_texture_height)),
                0);
        spa_pod_builder_add(b, SPA_FORMAT_VIDEO_framerate,
                SPA_POD_CHOICE_RANGE_Fraction(
                        &SPA_FRACTION(25,1),
                        &SPA_FRACTION(0,1),
                        &SPA_FRACTION(30,1)),
                0);
        return spa_pod_builder_pop(b, &f[0]);
}
 
/* 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;
        struct spa_data *d;
        void *sdata, *ddata;
        int sstride, dstride, ostride;
        uint32_t i;
        uint8_t *src, *dst;
        bool needs_unmap = false;
 
        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;
        d = buf->datas;
 
        pw_log_info("new buffer %p", buf);
 
        handle_events(data);
 
#ifdef EMULATE_DMA_BUF_IMPORT_FAIL
        if (buf->datas[0].type == SPA_DATA_DmaBuf) {
                // Simulate a failed import of a DmaBuf
                // We should try another modifier
                printf("Failed to import dmabuf, stripping modifier %"PRIu64"\n", data->format.info.raw.modifier);
                strip_modifier(data, data->format.info.raw.format, data->format.info.raw.modifier);
                pw_loop_signal_event(pw_main_loop_get_loop(data->loop), data->reneg);
                goto done;
        }
#endif
 
        if (buf->datas[0].type == SPA_DATA_DmaBuf) {
                sdata = mmap(NULL, d[0].maxsize, PROT_READ,
                        MAP_SHARED, d[0].fd, d[0].mapoffset);
                needs_unmap = true;
        } else {
                sdata = buf->datas[0].data;
        }
 
        if (sdata == 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:
        if (needs_unmap)
                munmap(d[0].data, d[0].maxsize);
        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:
                break;
        case PW_STREAM_STATE_STREAMING:
        default:
                break;
        }
}
 
static void
collect_device_ids(struct data *data, const char *json)
{
        struct spa_json it;
        int len;
        const char *value;
        struct spa_json sub;
        char key[1024];
 
        if ((len = spa_json_begin(&it, json, strlen(json), &value)) <= 0) {
                fprintf(stderr, "invalid device IDs value\n");
                return;
        }
        if (!spa_json_is_object(value, len)) {
                fprintf(stderr, "device IDs not object\n");
                return;
        }
 
        spa_json_enter(&it, &sub);
        while ((len = spa_json_object_next(&sub, key, sizeof(key), &value)) > 0) {
                struct spa_json devices_sub;
 
                if (!spa_json_is_array(value, len)) {
                        fprintf(stderr, "available-devices not array\n");
                        return;
                }
 
                spa_json_enter(&sub, &devices_sub);
                while ((len = spa_json_next(&devices_sub, &value)) > 0) {
                        char *string;
                        union {
                                dev_t device_id;
                                uint8_t buffer[1024];
                        } dec;
 
                        string = alloca(len + 1);
 
                        if (!spa_json_is_string(value, len)) {
                                fprintf(stderr, "device ID not string\n");
                                return;
                        }
 
                        if (spa_json_parse_string(value, len, string) <= 0) {
                                fprintf(stderr, "invalid device ID string\n");
                                return;
                        }
 
                        if (decode_hex(string, dec.buffer, sizeof (dec.buffer)) < 0) {
                                fprintf(stderr, "invalid device ID string\n");
                                return;
                        }
 
                        fprintf(stderr, "discovered device ID %u:%u\n",
                                major(dec.device_id), minor(dec.device_id));
 
                        data->device_ids[data->n_device_ids++] = dec.device_id;
                }
        }
}
 
static void
discover_capabilities(struct data *data, const struct spa_pod *param)
{
#ifdef SUPPORT_DEVICE_ID_NEGOTIATION
        struct spa_peer_param_info info;
        void *state = NULL;
 
        while (spa_peer_param_parse(param, &info, sizeof(info), &state) == 1) {
                struct spa_param_dict_info di;
 
                if (spa_param_dict_parse(info.param, &di, sizeof(di)) > 0) {
                        struct spa_dict dict;
                        struct spa_dict_item *items;
                        const struct spa_dict_item *it;
 
                        if (spa_param_dict_info_parse(&di, sizeof(di), &dict, NULL) < 0)
                                return;
 
                        items = alloca(sizeof(struct spa_dict_item) * dict.n_items);
                        if (spa_param_dict_info_parse(&di, sizeof(di), &dict, items) < 0)
                                return;
 
                        spa_dict_for_each(it, &dict) {
                                if (spa_streq(it->key, PW_CAPABILITY_DEVICE_ID_NEGOTIATION)) {
                                    int version = atoi(it->value);
                                    if (version >= 1)
                                        data->device_negotiation_supported = true;
                                } else if (spa_streq(it->key, PW_CAPABILITY_DEVICE_IDS)) {
                                        collect_device_ids(data, it->value);
                                }
                        }
                }
        }
#endif /* SUPPORT_DEVICE_ID_NEGOTIATION */
}
 
static void
on_stream_peer_capability_changed(struct data *data, const struct spa_pod *param)
{
        struct pw_stream *stream = data->stream;
 
        printf("peer capability param changed: \n");
        spa_debug_pod(4, NULL, param);
 
        discover_capabilities(data, param);
 
        if (!data->capabilities_known) {
                const struct spa_pod *params[MAX_PARAMS];
                uint32_t n_params = 0;
                uint8_t buffer[1024];
                struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));
 
                data->capabilities_known = true;
 
                if (data->device_negotiation_supported)
                        printf("stream supports device negotiation\n");
                else
                        printf("stream does not support device negotiation\n");
 
                /* 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. */
                printf("supported formats:\n");
 
                n_params = build_formats(data, &b, params);
                pw_stream_update_params(data->stream, params, n_params);
 
                printf("activating stream\n");
                pw_stream_set_active(stream, true);
        }
}
 
static int
find_device_id_from_param(const struct spa_pod *format, dev_t *device_id)
{
        const struct spa_pod_prop *device_prop;
        const void *bytes;
        uint32_t size;
 
        device_prop = spa_pod_find_prop(format, NULL, SPA_FORMAT_VIDEO_deviceId);
        if (device_prop == NULL)
                return -ENOENT;
 
        if (spa_pod_parse_object (format, SPA_TYPE_OBJECT_Format, NULL,
                                  SPA_FORMAT_VIDEO_deviceId, SPA_POD_OPT_Bytes(&bytes, &size)) < 0)
                return -EINVAL;
 
        if (size != sizeof(dev_t))
                return -EINVAL;
 
        *device_id = *(dev_t *)bytes;
 
        return 0;
}
 
/* Be notified when the stream format param 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_format_changed(struct data *data, const struct spa_pod *param)
{
        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[MAX_PARAMS];
        uint32_t n_params = 0;
        Uint32 sdl_format;
        void *d;
 
        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 (data->device_negotiation_supported) {
                dev_t device_id;
 
                if (find_device_id_from_param(param, &device_id) == 0) {
                        size_t i;
 
                        for (i = 0; i < SPA_N_ELEMENTS(devices); i++) {
                                if (major(device_id) == devices[i].major &&
                                    minor(device_id) == devices[i].minor) {
                                        data->used_device_index = i;
                                        printf("using negotiated device %u:%u\n",
                                                devices[i].major, devices[i].minor);
                                        break;
                                }
                        }
                }
        } else {
                data->used_device_index = 0;
                printf("using implicitly assumed device %u:%u\n",
                       devices[0].major, devices[0].minor);
        }
 
        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);
        if (SDL_LockTexture(data->texture, NULL, &d, &data->stride) < 0) {
                pw_stream_set_error(stream, -EINVAL, "invalid texture format");
                return;
        }
        SDL_UnlockTexture(data->texture);
 
        /* a SPA_TYPE_OBJECT_ParamBuffers object defines the acceptable size,
         * number, stride etc of the buffers */
        params[n_params++] = 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) | (1<<SPA_DATA_DmaBuf)));
 
        /* we are done */
        pw_stream_update_params(stream, params, n_params);
}
 
static void
on_stream_param_changed(void *_data, uint32_t id, const struct spa_pod *param)
{
        struct data *data = _data;
 
        if (param == NULL)
                return;
 
        switch (id) {
        case SPA_PARAM_PeerCapability:
                on_stream_peer_capability_changed(data, param);
                break;
        case SPA_PARAM_Format:
                on_stream_format_changed(data, param);
                break;
        }
}
 
/* 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 bool
has_device_id(struct data *data, dev_t device_id)
{
        size_t i;
 
        if (data->n_device_ids == 0)
                return true;
 
        for (i = 0; i < data->n_device_ids; i++) {
                if (data->device_ids[i] == device_id)
                        return true;
        }
 
        return false;
}
 
static int build_formats(struct data *data, struct spa_pod_builder *b, const struct spa_pod **params)
{
        SDL_RendererInfo info;
        int n_params = 0;
 
        SDL_GetRendererInfo(data->renderer, &info);
 
        if (data->device_negotiation_supported) {
                size_t i;
 
                for (i = 0; i < SPA_N_ELEMENTS(devices); i++) {
                        dev_t device_id;
 
                        device_id = makedev(devices[i].major, devices[i].minor);
                        if (!has_device_id(data, device_id)) {
                                fprintf(stderr, "filtered out %u:%u\n",
                                        devices[i].major, devices[i].minor);
                                continue;
                        }
 
                        params[n_params++] = build_format(data, b,
                                        &info, SPA_VIDEO_FORMAT_RGBA, i);
                }
        } else {
                params[n_params++] = build_format(data, b,
                                &info, SPA_VIDEO_FORMAT_RGBA, 0);
        }
 
        params[n_params++] = build_format(data, b, &info, SPA_VIDEO_FORMAT_RGBA, -1);
 
        for (int i=0; i < n_params; i++) {
                spa_debug_format(2, NULL, params[i]);
        }
        return n_params;
}
 
static void reneg_format(void *_data, uint64_t expiration)
{
        struct data *data = (struct data*) _data;
        uint8_t buffer[1024];
        struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));
        const struct spa_pod *params[MAX_PARAMS];
        uint32_t n_params;
 
        if (data->format.info.raw.format == 0)
                return;
 
        fprintf(stderr, "renegotiate formats:\n");
        n_params = build_formats(data, &b, params);
 
        pw_stream_update_params(data->stream, params, n_params);
}
 
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[MAX_PARAMS];
        uint8_t buffer[1024];
        struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));
        struct spa_pod_frame f;
        struct pw_properties *props;
        int res, n_params = 0;
        SDL_RendererInfo info;
 
        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.used_device_index = -1;
        data.stream = pw_stream_new_simple(
                        pw_main_loop_get_loop(data.loop),
                        "video-play-fixate",
                        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;
        }
 
        SDL_GetRendererInfo(data.renderer, &info);
 
        /* Push bare minimum video format to inactive stream, and wait for
         * sending actual format until capability discovery is done. */
        spa_pod_builder_push_object(&b, &f, SPA_TYPE_OBJECT_Format, SPA_PARAM_EnumFormat);
        spa_pod_builder_add(&b, SPA_FORMAT_mediaType,
                SPA_POD_Id (SPA_MEDIA_TYPE_video),
                0);
        spa_pod_builder_add(&b, SPA_FORMAT_mediaSubtype,
                SPA_POD_Id (SPA_MEDIA_SUBTYPE_raw),
                0);
        spa_pod_builder_add(&b, SPA_FORMAT_VIDEO_format,
                SPA_POD_Id(SPA_VIDEO_FORMAT_RGBA),
                0);
        spa_pod_builder_add(&b, SPA_FORMAT_VIDEO_size,
                SPA_POD_CHOICE_RANGE_Rectangle(
                        &SPA_RECTANGLE(WIDTH, HEIGHT),
                        &SPA_RECTANGLE(1,1),
                        &SPA_RECTANGLE(info.max_texture_width,
                                       info.max_texture_height)),
                0);
        params[n_params++] = spa_pod_builder_pop(&b, &f);
 
#ifdef SUPPORT_DEVICE_ID_NEGOTIATION
        params[n_params++] =
                spa_param_dict_build_dict(&b, SPA_PARAM_Capability,
                        &SPA_DICT_ITEMS(
                                SPA_DICT_ITEM(PW_CAPABILITY_DEVICE_ID_NEGOTIATION, "1")));
#endif
 
        /* 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_INACTIVE |     /* set active after capability discovery */
                          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.reneg = pw_loop_add_event(pw_main_loop_get_loop(data.loop), reneg_format, &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;
}