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linux-capture: Announce supported modifiers via pipewire
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Sharing DMA-BUFs via PipeWire requires the client to announce all
formats together with their supported modifiers. [1]

[1] https://docs.pipewire.org/page_dma_buf.html
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@columbarius
columbarius committed Sep 16, 2021
1 parent b7896ae commit 5bf2bbf
Showing 1 changed file with 140 additions and 19 deletions.
159 changes: 140 additions & 19 deletions plugins/linux-capture/pipewire.c
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Original file line number Diff line number Diff line change
Expand Up @@ -60,6 +60,13 @@
fourcc_code('A', 'B', '2', \
'4') /* [31:0] A:B:G:R 8:8:8:8 little endian */

struct modifier_info {
uint32_t spa_format;
uint32_t drm_format;
int32_t n_modifiers;
uint64_t *modifiers;
};

struct _obs_pipewire_data {
GCancellable *cancellable;

Expand Down Expand Up @@ -104,6 +111,9 @@ struct _obs_pipewire_data {
enum obs_pw_capture_type capture_type;
struct obs_video_info video_info;
bool negotiated;

int n_formats;
struct modifier_info *modifier_info;
};

struct dbus_call_data {
Expand Down Expand Up @@ -343,6 +353,124 @@ static void swap_texture_red_blue(gs_texture_t *texture)
glBindTexture(GL_TEXTURE_2D, 0);
}

static inline struct spa_pod *build_format(struct spa_pod_builder *b,
struct obs_video_info *ovi,
uint32_t format, uint64_t *modifiers,
size_t modifier_count)
{
uint32_t i, c;
struct spa_pod_frame f[2];

/* make an object of type SPA_TYPE_OBJECT_Format and id SPA_PARAM_EnumFormat.
* The object type is important because it defines the properties that are
* acceptable. The id gives more context about what the object is meant to
* contain. In this case we enumerate supported formats. */
spa_pod_builder_push_object(b, &f[0], SPA_TYPE_OBJECT_Format,
SPA_PARAM_EnumFormat);
/* add media type and media subtype properties */
spa_pod_builder_prop(b, SPA_FORMAT_mediaType, 0);
spa_pod_builder_id(b, SPA_MEDIA_TYPE_video);
spa_pod_builder_prop(b, SPA_FORMAT_mediaSubtype, 0);
spa_pod_builder_id(b, SPA_MEDIA_SUBTYPE_raw);

/* formats */
spa_pod_builder_prop(b, SPA_FORMAT_VIDEO_format, 0);
spa_pod_builder_id(b, format);

/* modifier */
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 an array */
for (i = 0, c = 0; i < modifier_count; i++) {
uint64_t modifier = modifiers[i];
spa_pod_builder_long(b, modifier);
if (c++ == 0)
spa_pod_builder_long(b, modifier);
}
spa_pod_builder_pop(b, &f[1]);
}
/* add size and framerate ranges */
spa_pod_builder_add(b, SPA_FORMAT_VIDEO_size,
SPA_POD_CHOICE_RANGE_Rectangle(
&SPA_RECTANGLE(320, 240), // Arbitrary
&SPA_RECTANGLE(1, 1),
&SPA_RECTANGLE(8192, 4320)),
SPA_FORMAT_VIDEO_framerate,
SPA_POD_CHOICE_RANGE_Fraction(
&SPA_FRACTION(ovi->fps_num, ovi->fps_den),
&SPA_FRACTION(0, 1), &SPA_FRACTION(360, 1)),
0);
return spa_pod_builder_pop(b, &f[0]);
}

static uint32_t build_format_params(obs_pipewire_data *obs_pw,
struct spa_pod_builder *pod_builder,
const struct spa_pod ***param_list)
{
uint32_t n_params = 0;

const struct spa_pod **params;
params = bzalloc(2 * obs_pw->n_formats * sizeof(struct spa_pod *));

for (int i = 0; i < obs_pw->n_formats; i++) {
if (obs_pw->modifier_info[i].n_modifiers == 0) {
continue;
}
params[n_params++] =
build_format(pod_builder, &obs_pw->video_info,
obs_pw->modifier_info[i].spa_format,
obs_pw->modifier_info[i].modifiers,
obs_pw->modifier_info[i].n_modifiers);
}
for (int i = 0; i < obs_pw->n_formats; i++) {
params[n_params++] = build_format(
pod_builder, &obs_pw->video_info,
obs_pw->modifier_info[i].spa_format, NULL, 0);
}
*param_list = params;
return n_params;
}

static uint32_t create_modifier_info(struct modifier_info **modifier_info)
{
uint32_t formats[] = {
SPA_VIDEO_FORMAT_BGRA,
SPA_VIDEO_FORMAT_RGBA,
SPA_VIDEO_FORMAT_BGRx,
SPA_VIDEO_FORMAT_RGBx,
};

int32_t n_formats = sizeof(formats) / sizeof(formats[0]);

struct modifier_info *info =
bzalloc(n_formats * sizeof(struct modifier_info));
obs_enter_graphics();
for (int i = 0; i < n_formats; i++) {
info[i].spa_format = formats[i];
spa_pixel_format_to_drm_format(formats[i], &info[i].drm_format);
info[i].n_modifiers = gs_query_dmabuf_modifiers(
info[i].drm_format, &info[i].modifiers);
}
obs_leave_graphics();

*modifier_info = info;
return n_formats;
}

static void destroy_modifier_info(int32_t n_formats,
struct modifier_info *modifier_info)
{
for (int i = 0; i < n_formats; i++) {
bfree(modifier_info[i].modifiers);
modifier_info[i].modifiers = NULL;
modifier_info[i].n_modifiers = 0;
}
bfree(modifier_info);
}
/* ------------------------------------------------- */

static void on_process_cb(void *user_data)
Expand Down Expand Up @@ -630,8 +758,9 @@ static const struct pw_core_events core_events = {
static void play_pipewire_stream(obs_pipewire_data *obs_pw)
{
struct spa_pod_builder pod_builder;
const struct spa_pod *params[1];
uint8_t params_buffer[1024];
const struct spa_pod **params = NULL;
uint32_t n_params;
uint8_t params_buffer[2048];
struct obs_video_info ovi;

obs_pw->thread_loop = pw_thread_loop_new("PipeWire thread loop", NULL);
Expand Down Expand Up @@ -673,32 +802,20 @@ static void play_pipewire_stream(obs_pipewire_data *obs_pw)
SPA_POD_BUILDER_INIT(params_buffer, sizeof(params_buffer));

obs_get_video_info(&ovi);
params[0] = spa_pod_builder_add_object(
&pod_builder, 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_CHOICE_ENUM_Id(
4, SPA_VIDEO_FORMAT_BGRA, SPA_VIDEO_FORMAT_RGBA,
SPA_VIDEO_FORMAT_BGRx, SPA_VIDEO_FORMAT_RGBx),
SPA_FORMAT_VIDEO_size,
SPA_POD_CHOICE_RANGE_Rectangle(
&SPA_RECTANGLE(320, 240), // Arbitrary
&SPA_RECTANGLE(1, 1), &SPA_RECTANGLE(8192, 4320)),
SPA_FORMAT_VIDEO_framerate,
SPA_POD_CHOICE_RANGE_Fraction(
&SPA_FRACTION(ovi.fps_num, ovi.fps_den),
&SPA_FRACTION(0, 1), &SPA_FRACTION(360, 1)));

obs_pw->video_info = ovi;

n_params = build_format_params(obs_pw, &pod_builder, &params);

pw_stream_connect(
obs_pw->stream, PW_DIRECTION_INPUT, obs_pw->pipewire_node,
PW_STREAM_FLAG_AUTOCONNECT | PW_STREAM_FLAG_MAP_BUFFERS, params,
1);
n_params);

blog(LOG_INFO, "[pipewire] playing stream…");

pw_thread_loop_unlock(obs_pw->thread_loop);
bfree(params);
}

/* ------------------------------------------------- */
Expand Down Expand Up @@ -1128,6 +1245,8 @@ void *obs_pipewire_create(enum obs_pw_capture_type capture_type,
if (!init_obs_pipewire(obs_pw))
g_clear_pointer(&obs_pw, bfree);

obs_pw->n_formats = create_modifier_info(&obs_pw->modifier_info);

return obs_pw;
}

Expand All @@ -1139,6 +1258,8 @@ void obs_pipewire_destroy(obs_pipewire_data *obs_pw)
teardown_pipewire(obs_pw);
destroy_session(obs_pw);

destroy_modifier_info(obs_pw->n_formats, obs_pw->modifier_info);

bfree(obs_pw);
}

Expand Down

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