PipeWire 0.3.80
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Video input stream using pw_stream, with format fixation.

/* PipeWire */
/* SPDX-FileCopyrightText: Copyright © 2020 Wim Taymans */
/* SPDX-License-Identifier: MIT */
Video input stream using \ref pw_stream "pw_stream", with format fixation.
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <libdrm/drm_fourcc.h>
#include <spa/param/video/format-utils.h>
#define WIDTH 640
#define HEIGHT 480
#define MAX_BUFFERS 64
#define MAX_MOD 8
#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 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;
uint32_t n_mod_info;
struct modifier_info mod_info[2];
int counter;
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,
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,
return major <= pw_version.major && minor <= pw_version.minor && micro <= pw_version.micro;
static void init_modifiers(struct data *data)
data->n_mod_info = 1;
data->mod_info[0].spa_format = SPA_VIDEO_FORMAT_RGB;
data->mod_info[0].n_modifiers = 2;
data->mod_info[0].modifiers[0] = DRM_FORMAT_MOD_LINEAR;
data->mod_info[0].modifiers[1] = DRM_FORMAT_MOD_INVALID;
static void destroy_modifiers(struct data *data)
data->mod_info[0].n_modifiers = 0;
static void strip_modifier(struct data *data, uint32_t spa_format, uint64_t modifier)
if (data->mod_info[0].spa_format != spa_format)
struct modifier_info *mod_info = &data->mod_info[0];
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\n");
for (uint32_t i = 0; i < mod_info->n_modifiers; i++) {
if (mod_info->modifiers[i] == modifier)
mod_info->modifiers[counter++] = mod_info->modifiers[i];
} else {
printf("Dropping all modifiers\n");
counter = 0;
mod_info->n_modifiers = counter;
static void handle_events(struct data *data)
SDL_Event event;
while (SDL_PollEvent(&event)) {
switch (event.type) {
case SDL_QUIT:
static struct spa_pod *build_format(struct spa_pod_builder *b, SDL_RendererInfo *info, enum spa_video_format format,
uint64_t *modifiers, int modifier_count)
struct spa_pod_frame f[2];
int i, c;
/* format */
/* 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_long(b, modifiers[0]);
} else if (modifier_count > 0) {
// build an enumeration of modifiers
// 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]);
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;
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)
if (b)
b = t;
if (b == NULL) {
pw_log_warn("out of buffers: %m");
buf = b->buffer;
pw_log_info("new buffer %p", buf);
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;
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;
/* now render the video */
SDL_RenderCopy(data->renderer, data->texture, NULL, NULL);
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) {
/* 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)
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)
if (data->format.media_type != SPA_MEDIA_TYPE_video ||
data->format.media_subtype != SPA_MEDIA_SUBTYPE_raw)
/* 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");
if (data->size.width == 0 || data->size.height == 0) {
pw_stream_set_error(stream, -EINVAL, "invalid size");
data->texture = SDL_CreateTexture(data->renderer,
SDL_LockTexture(data->texture, NULL, &d, &data->stride);
/* a SPA_TYPE_OBJECT_ParamBuffers object defines the acceptable size,
* number, stride etc of the buffers */
SPA_PARAM_BUFFERS_size, SPA_POD_Int(data->stride * data->size.height),
/* 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 = {
.state_changed = on_stream_state_changed,
.param_changed = on_stream_param_changed,
.process = on_process,
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->mod_info[0].n_modifiers > 0) {
params[n_params++] = build_format(b, &info, SPA_VIDEO_FORMAT_RGB, data->mod_info[0].modifiers, data->mod_info[0].n_modifiers);
params[n_params++] = build_format(b, &info, SPA_VIDEO_FORMAT_RGB, NULL, 0);
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[2];
uint32_t n_params;
if (data->format.info.raw.format == 0)
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;
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.
data.path = argc > 1 ? argv[1] : NULL;
if (data.path)
/* Set stream target if given on command line */
data.stream = pw_stream_new_simple(
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. */
printf("supported formats:\n");
n_params = build_formats(&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_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.reneg = pw_loop_add_event(pw_main_loop_get_loop(data.loop), reneg_format, &data);
/* do things until we quit the mainloop */
if (data.cursor)
return 0;
#define PW_ID_ANY
Definition: core.h:66
Definition: src/pipewire/keys.h:431
a target object to link to.
Definition: src/pipewire/keys.h:496
Role: Movie, Music, Camera, Screen, Communication, Game, Notification, DSP, Production,...
Definition: src/pipewire/keys.h:437
Media Category: Playback, Capture, Duplex, Monitor, Manager.
Definition: src/pipewire/keys.h:434
#define pw_log_warn(...)
Definition: src/pipewire/log.h:143
#define pw_log_info(...)
Definition: src/pipewire/log.h:144
#define pw_loop_add_signal(l,...)
Definition: src/pipewire/loop.h:63
#define pw_loop_signal_event(l,...)
Definition: src/pipewire/loop.h:60
#define pw_loop_add_event(l,...)
Definition: src/pipewire/loop.h:59
int pw_main_loop_quit(struct pw_main_loop *loop)
Quit a main loop.
Definition: main-loop.c:105
void pw_main_loop_destroy(struct pw_main_loop *loop)
Destroy a loop.
Definition: main-loop.c:70
int pw_main_loop_run(struct pw_main_loop *loop)
Run a main loop.
Definition: main-loop.c:119
struct pw_main_loop * pw_main_loop_new(const struct spa_dict *props)
Create a new main loop.
Definition: main-loop.c:60
struct pw_loop * pw_main_loop_get_loop(struct pw_main_loop *loop)
Get the loop implementation.
Definition: main-loop.c:93
void pw_init(int *argc, char **argv[])
Initialize PipeWire.
Definition: pipewire.c:555
void pw_deinit(void)
Deinitialize PipeWire.
Definition: pipewire.c:668
Definition: port.h:48
struct pw_properties * pw_properties_new(const char *key,...) 1
Make a new properties object.
Definition: properties.c:84
int pw_properties_set(struct pw_properties *properties, const char *key, const char *value)
Set a property value.
Definition: properties.c:421
int int pw_stream_update_params(struct pw_stream *stream, const struct spa_pod **params, uint32_t n_params)
Update the param exposed on the stream.
Definition: stream.c:2187
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:1882
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:2385
int pw_stream_set_error(struct pw_stream *stream, int res, const char *error,...) 1(3
Set the stream in error state.
const char * pw_stream_state_as_string(enum pw_stream_state state)
Convert a stream state to a readable string.
Definition: stream.c:1625
The state of a stream.
Definition: stream.h:184
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:2413
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:1581
Definition: stream.h:330
void pw_stream_destroy(struct pw_stream *stream)
Destroy a stream.
Definition: stream.c:1675
mmap the buffers except DmaBuf
Definition: stream.h:378
try to automatically connect this stream
Definition: stream.h:373
Definition: stream.h:188
Definition: stream.h:186
Definition: stream.h:189
pointer to memory, the data field in struct spa_data is set.
Definition: buffer/buffer.h:33
fd to dmabuf memory
Definition: buffer/buffer.h:36
static int spa_debug_format(int indent, const struct spa_type_info *info, const struct spa_pod *format)
Definition: debug/format.h:206
static int spa_format_parse(const struct spa_pod *format, uint32_t *media_type, uint32_t *media_subtype)
Definition: format-utils.h:27
properties for audio SPA_TYPE_OBJECT_Format
Definition: param/format.h:90
static int spa_format_video_raw_parse(const struct spa_pod *format, struct spa_video_info_raw *info)
Definition: video/raw-utils.h:27
Video formats.
Definition: video/raw.h:43
Definition: param/format.h:28
@ SPA_PARAM_Format
configured format as SPA_TYPE_OBJECT_Format
Definition: param.h:34
@ SPA_PARAM_EnumFormat
available formats as SPA_TYPE_OBJECT_Format
Definition: param.h:33
@ SPA_PARAM_Buffers
buffer configurations as SPA_TYPE_OBJECT_ParamBuffers
Definition: param.h:35
@ SPA_FORMAT_VIDEO_framerate
frame rate (Fraction)
Definition: param/format.h:124
@ SPA_FORMAT_mediaType
media type (Id enum spa_media_type)
Definition: param/format.h:93
size (Rectangle)
Definition: param/format.h:123
format modifier (Long) use only with DMA-BUF and omit for other buffer types
Definition: param/format.h:121
video format (Id enum spa_video_format)
Definition: param/format.h:120
@ SPA_FORMAT_mediaSubtype
media subtype (Id enum spa_media_subtype)
Definition: param/format.h:94
Definition: param/format.h:38
Definition: video/raw.h:60
possible memory types (Int, mask of enum spa_data_type)
Definition: spa/include/spa/param/buffers.h:32
size of a data block memory (Int)
Definition: spa/include/spa/param/buffers.h:29
stride of data block memory (Int)
Definition: spa/include/spa/param/buffers.h:30
number of data blocks per buffer (Int)
Definition: spa/include/spa/param/buffers.h:28
number of buffers (Int)
Definition: spa/include/spa/param/buffers.h:27
static int spa_pod_builder_prop(struct spa_pod_builder *builder, uint32_t key, uint32_t flags)
Definition: builder.h:450
#define SPA_POD_CHOICE_RANGE_Fraction(def, min, max)
Definition: vararg.h:115
is mandatory
Definition: pod/pod.h:222
static int spa_pod_builder_add(struct spa_pod_builder *builder,...)
Definition: builder.h:647
#define SPA_POD_CHOICE_RANGE_Int(def, min, max)
Definition: vararg.h:58
#define SPA_POD_Id(val)
Definition: vararg.h:49
#define SPA_POD_BUILDER_INIT(buffer, size)
Definition: builder.h:62
static void * spa_pod_builder_pop(struct spa_pod_builder *builder, struct spa_pod_frame *frame)
Definition: builder.h:168
#define SPA_POD_CHOICE_RANGE_Rectangle(def, min, max)
Definition: vararg.h:106
choices need no fixation
Definition: pod/pod.h:224
#define spa_pod_builder_add_object(b, type, id,...)
Definition: builder.h:659
static int spa_pod_builder_push_choice(struct spa_pod_builder *builder, struct spa_pod_frame *frame, uint32_t type, uint32_t flags)
Definition: builder.h:406
static int spa_pod_builder_push_object(struct spa_pod_builder *builder, struct spa_pod_frame *frame, uint32_t type, uint32_t id)
Definition: builder.h:435
static int spa_pod_builder_long(struct spa_pod_builder *builder, int64_t val)
Definition: builder.h:256
#define SPA_POD_Int(val)
Definition: vararg.h:54
#define SPA_POD_CHOICE_FLAGS_Int(flags)
Definition: vararg.h:62
list: default, alternative,...
Definition: pod/pod.h:150
#define spa_strerror(err)
Definition: result.h:49
@ SPA_TYPE_OBJECT_ParamBuffers
Definition: spa/include/spa/utils/type.h:77
Definition: spa/include/spa/utils/type.h:76
#define SPA_MIN(a, b)
Definition: defs.h:151
#define SPA_FRACTION(num, denom)
Definition: defs.h:122
#define SPA_RECTANGLE(width, height)
Definition: defs.h:101
a buffer structure obtained from pw_stream_dequeue_buffer().
Definition: stream.h:194
struct spa_buffer * buffer
the spa buffer
Definition: stream.h:195
A main loop object.
Definition: properties.h:33
Events for a stream.
Definition: stream.h:328
A Buffer.
Definition: buffer/buffer.h:90
struct spa_data * datas
array of data members
Definition: buffer/buffer.h:94
int32_t stride
stride of valid data
Definition: buffer/buffer.h:49
uint32_t size
size of valid data.
Definition: buffer/buffer.h:47
struct spa_chunk * chunk
valid chunk of memory
Definition: buffer/buffer.h:86
void * data
optional data pointer
Definition: buffer/buffer.h:85
uint32_t type
memory type, one of enum spa_data_type, when allocating memory, the type contains a bitmask of allowe...
Definition: buffer/buffer.h:63
A hook, contains the structure with functions and the data passed to the functions.
Definition: hook.h:350
Definition: builder.h:53
Definition: iter.h:27
Definition: pod/pod.h:43
Definition: defs.h:102
Definition: spa/include/spa/support/loop.h:55
Definition: param/video/format.h:27