PipeWire  0.3.58
tutorial5.c

Tutorial - Part 5: Capturing Video Frames

/*
[title]
\ref page_tutorial5
[title]
*/
/* [code] */
struct data {
struct pw_main_loop *loop;
struct pw_stream *stream;
struct spa_video_info format;
};
/* [on_process] */
static void on_process(void *userdata)
{
struct data *data = userdata;
struct pw_buffer *b;
struct spa_buffer *buf;
if ((b = pw_stream_dequeue_buffer(data->stream)) == NULL) {
pw_log_warn("out of buffers: %m");
return;
}
buf = b->buffer;
if (buf->datas[0].data == NULL)
return;
printf("got a frame of size %d\n", buf->datas[0].chunk->size);
pw_stream_queue_buffer(data->stream, b);
}
/* [on_process] */
static void on_param_changed(void *userdata, uint32_t id, const struct spa_pod *param)
{
struct data *data = userdata;
if (param == NULL || id != SPA_PARAM_Format)
return;
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;
if (spa_format_video_raw_parse(param, &data->format.info.raw) < 0)
return;
printf("got video format:\n");
printf(" format: %d (%s)\n", data->format.info.raw.format,
data->format.info.raw.format));
printf(" size: %dx%d\n", data->format.info.raw.size.width,
data->format.info.raw.size.height);
printf(" framerate: %d/%d\n", data->format.info.raw.framerate.num,
data->format.info.raw.framerate.denom);
}
static const struct pw_stream_events stream_events = {
.param_changed = on_param_changed,
.process = on_process,
};
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));
struct pw_properties *props;
pw_init(&argc, &argv);
data.loop = pw_main_loop_new(NULL);
PW_KEY_MEDIA_ROLE, "Camera",
NULL);
if (argc > 1)
data.stream = pw_stream_new_simple(
"video-capture",
props,
&stream_events,
&data);
&SPA_RECTANGLE(320, 240),
&SPA_RECTANGLE(1, 1),
&SPA_RECTANGLE(4096, 4096)),
&SPA_FRACTION(25, 1),
&SPA_FRACTION(0, 1),
&SPA_FRACTION(1000, 1)));
pw_stream_connect(data.stream,
params, 1);
pw_main_loop_run(data.loop);
pw_stream_destroy(data.stream);
return 0;
}
/* [code] */
#define PW_ID_ANY
Definition: core.h:83
#define PW_KEY_MEDIA_TYPE
Media.
Definition: keys.h:438
#define PW_KEY_TARGET_OBJECT
a target object to link to
Definition: keys.h:508
#define PW_KEY_MEDIA_ROLE
Role: Movie, Music, Camera, Screen, Communication, Game, Notification, DSP, Production,...
Definition: keys.h:444
#define PW_KEY_MEDIA_CATEGORY
Media Category: Playback, Capture, Duplex, Monitor, Manager.
Definition: keys.h:441
#define pw_log_warn(...)
Definition: log.h:163
struct pw_main_loop * pw_main_loop_new(const struct spa_dict *props)
Create a new main loop.
Definition: main-loop.c:80
void pw_main_loop_destroy(struct pw_main_loop *loop)
Destroy a loop.
Definition: main-loop.c:90
int pw_main_loop_run(struct pw_main_loop *loop)
Run a main loop.
Definition: main-loop.c:139
struct pw_loop * pw_main_loop_get_loop(struct pw_main_loop *loop)
Get the loop implementation.
Definition: main-loop.c:113
void pw_init(int *argc, char **argv[])
Initialize PipeWire.
Definition: pipewire.c:580
#define PW_DIRECTION_INPUT
Definition: port.h:65
struct pw_properties * pw_properties_new(const char *key,...) 1
Make a new properties object.
Definition: properties.c:102
int pw_properties_set(struct pw_properties *properties, const char *key, const char *value)
Set a property value.
Definition: properties.c:439
int pw_stream_connect(struct pw_stream *stream, enum pw_direction direction, uint32_t target_id, enum pw_stream_flags flags, const struct spa_pod **params, uint32_t n_params)
Connect a stream for input or output on port_path.
Definition: stream.c:1792
struct pw_stream * pw_stream_new_simple(struct pw_loop *loop, const char *name, struct pw_properties *props, const struct pw_stream_events *events, void *data)
Definition: stream.c:1539
struct pw_buffer * pw_stream_dequeue_buffer(struct pw_stream *stream)
Get a buffer that can be filled for playback streams or consumed for capture streams.
Definition: stream.c:2247
int pw_stream_queue_buffer(struct pw_stream *stream, struct pw_buffer *buffer)
Submit a buffer for playback or recycle a buffer for capture.
Definition: stream.c:2274
#define PW_VERSION_STREAM_EVENTS
Definition: stream.h:337
void pw_stream_destroy(struct pw_stream *stream)
Destroy a stream.
Definition: stream.c:1601
@ PW_STREAM_FLAG_MAP_BUFFERS
mmap the buffers except DmaBuf
Definition: stream.h:385
@ PW_STREAM_FLAG_AUTOCONNECT
try to automatically connect this stream
Definition: stream.h:380
static const char * spa_debug_type_find_name(const struct spa_type_info *info, uint32_t type)
Definition: types.h:73
static int spa_format_parse(const struct spa_pod *format, uint32_t *media_type, uint32_t *media_subtype)
Definition: format-utils.h:47
static const struct spa_type_info spa_type_video_format[]
Definition: type-info.h:48
static int spa_format_video_raw_parse(const struct spa_pod *format, struct spa_video_info_raw *info)
Definition: format-utils.h:47
@ SPA_MEDIA_TYPE_video
Definition: format.h:48
@ SPA_PARAM_Format
configured format as SPA_TYPE_OBJECT_Format
Definition: param.h:54
@ SPA_PARAM_EnumFormat
available formats as SPA_TYPE_OBJECT_Format
Definition: param.h:53
@ SPA_FORMAT_VIDEO_framerate
frame rate (Fraction)
Definition: format.h:131
@ SPA_FORMAT_mediaType
media type (Id enum spa_media_type)
Definition: format.h:109
@ SPA_FORMAT_VIDEO_size
size (Rectangle)
Definition: format.h:130
@ SPA_FORMAT_VIDEO_format
video format (Id enum spa_video_format)
Definition: format.h:127
@ SPA_FORMAT_mediaSubtype
media subtype (Id enum spa_media_subtype)
Definition: format.h:110
@ SPA_MEDIA_SUBTYPE_raw
Definition: format.h:58
@ SPA_VIDEO_FORMAT_YUY2
Definition: raw.h:69
@ SPA_VIDEO_FORMAT_RGBA
Definition: raw.h:76
@ SPA_VIDEO_FORMAT_RGBx
Definition: raw.h:72
@ SPA_VIDEO_FORMAT_BGRx
Definition: raw.h:73
@ SPA_VIDEO_FORMAT_I420
Definition: raw.h:67
@ SPA_VIDEO_FORMAT_RGB
Definition: raw.h:80
#define SPA_POD_CHOICE_ENUM_Id(n_vals,...)
Definition: vararg.h:71
#define SPA_POD_CHOICE_RANGE_Fraction(def, min, max)
Definition: vararg.h:135
#define SPA_POD_Id(val)
Definition: vararg.h:69
#define SPA_POD_BUILDER_INIT(buffer, size)
Definition: builder.h:82
#define SPA_POD_CHOICE_RANGE_Rectangle(def, min, max)
Definition: vararg.h:126
#define spa_pod_builder_add_object(b, type, id,...)
Definition: builder.h:679
@ SPA_TYPE_OBJECT_Format
Definition: type.h:96
#define SPA_FRACTION(num, denom)
Definition: defs.h:137
#define SPA_RECTANGLE(width, height)
Definition: defs.h:116
spa/param/video/type-info.h
pipewire/pipewire.h
a buffer structure obtained from pw_stream_dequeue_buffer().
Definition: stream.h:210
struct spa_buffer * buffer
the spa buffer
Definition: stream.h:211
A main loop object.
Definition: properties.h:53
Events for a stream.
Definition: stream.h:335
A Buffer.
Definition: buffer.h:109
struct spa_data * datas
array of data members
Definition: buffer.h:113
uint32_t size
size of valid data.
Definition: buffer.h:66
struct spa_chunk * chunk
valid chunk of memory
Definition: buffer.h:105
void * data
optional data pointer
Definition: buffer.h:104
Definition: builder.h:73
Definition: pod.h:63
Definition: format.h:45
spa/debug/types.h