obs-transitions: Add stinger transition

Allows using a video file as a means of transitioning, transitioning two
targets at a specific time during the video playback.  Audio for target
A fades out to the transition point, and then audio for target B fades
in after the transition point.

plugins/obs-transitions/CMakeLists.txt

@@ -8,6 +8,7 @@ set(obs-transitions_SOURCES
 	transition-cut.c
 	transition-fade-to-color.c
 	transition-luma-wipe.c
+	transition-stinger.c
 	)
 
 add_library(obs-transitions MODULE

plugins/obs-transitions/data/locale/en-US.ini

@@ -2,6 +2,7 @@ FadeTransition="Fade"
 CutTransition="Cut"
 SwipeTransition="Swipe"
 SlideTransition="Slide"
+StingerTransition="Stinger"
 FadeToColorTransition="Fade to Color"
 Direction="Direction"
 Direction.Left="Left"
@@ -10,6 +11,8 @@ Direction.Up="Up"
 Direction.Down="Down"
 SwipeIn="Swipe In"
 Color="Color"
+VideoFile="Video File"
+TransitionPoint="Transition Point (milliseconds)"
 SwitchPoint="Peak Color Point (percentage)"
 LumaWipeTransition="Luma Wipe"
 LumaWipe.Image="Image"

plugins/obs-transitions/obs-transitions.c

@@ -8,6 +8,7 @@ extern struct obs_source_info cut_transition;
 extern struct obs_source_info fade_transition;
 extern struct obs_source_info swipe_transition;
 extern struct obs_source_info slide_transition;
+extern struct obs_source_info stinger_transition;
 extern struct obs_source_info fade_to_color_transition;
 extern struct obs_source_info luma_wipe_transition;
 
@@ -17,6 +18,7 @@ bool obs_module_load(void)
 	obs_register_source(&fade_transition);
 	obs_register_source(&swipe_transition);
 	obs_register_source(&slide_transition);
+	obs_register_source(&stinger_transition);
 	obs_register_source(&fade_to_color_transition);
 	obs_register_source(&luma_wipe_transition);
 	return true;

plugins/obs-transitions/transition-stinger.c

@@ -0,0 +1,254 @@
+#include <obs-module.h>
+
+struct stinger_info {
+	obs_source_t *source;
+
+	obs_source_t *media_source;
+
+	uint64_t duration_ns;
+	uint64_t transition_point_ns;
+	float transition_point;
+	float transition_a_mul;
+	float transition_b_mul;
+	bool transitioning;
+};
+
+static const char *stinger_get_name(void *type_data)
+{
+	UNUSED_PARAMETER(type_data);
+	return obs_module_text("StingerTransition");
+}
+
+static void stinger_update(void *data, obs_data_t *settings)
+{
+	struct stinger_info *s = data;
+	const char *path = obs_data_get_string(settings, "path");
+
+	obs_data_t *media_settings = obs_data_create();
+	obs_data_set_string(media_settings, "local_file", path);
+
+	obs_source_release(s->media_source);
+	s->media_source = obs_source_create_private("ffmpeg_source", NULL,
+			media_settings);
+	obs_data_release(media_settings);
+
+	int64_t point_ms = obs_data_get_int(settings, "transition_point");
+
+	s->transition_point_ns = (uint64_t)(point_ms * 1000000LL);
+}
+
+static void *stinger_create(obs_data_t *settings, obs_source_t *source)
+{
+	struct stinger_info *s = bzalloc(sizeof(*s));
+
+	s->source = source;
+
+	obs_transition_enable_fixed(s->source, true, 0);
+	obs_source_update(source, settings);
+	return s;
+}
+
+static void stinger_destroy(void *data)
+{
+	struct stinger_info *s = data;
+	obs_source_release(s->media_source);
+	bfree(s);
+}
+
+static void stinger_video_render(void *data, gs_effect_t *effect)
+{
+	struct stinger_info *s = data;
+
+	float t = obs_transition_get_time(s->source);
+	bool use_a = t < s->transition_point;
+
+	enum obs_transition_target target = use_a
+		? OBS_TRANSITION_SOURCE_A
+		: OBS_TRANSITION_SOURCE_B;
+
+	if (!obs_transition_video_render_direct(s->source, target))
+		return;
+
+	/* --------------------- */
+
+	float source_cx = (float)obs_source_get_width(s->source);
+	float source_cy = (float)obs_source_get_height(s->source);
+	uint32_t media_cx = obs_source_get_width(s->media_source);
+	uint32_t media_cy = obs_source_get_height(s->media_source);
+
+	if (!media_cx || !media_cy)
+		return;
+
+	float scale_x = source_cx / (float)media_cx;
+	float scale_y = source_cy / (float)media_cy;
+
+	gs_matrix_push();
+	gs_matrix_scale3f(scale_x, scale_y, 1.0f);
+	obs_source_video_render(s->media_source);
+	gs_matrix_pop();
+
+	UNUSED_PARAMETER(effect);
+}
+
+static inline float calc_fade(float t, float mul)
+{
+	t *= mul;
+	return t > 1.0f ? 1.0f : t;
+}
+
+static float mix_a(void *data, float t)
+{
+	struct stinger_info *s = data;
+	return 1.0f - calc_fade(t, s->transition_a_mul);
+}
+
+static float mix_b(void *data, float t)
+{
+	struct stinger_info *s = data;
+	return 1.0f - calc_fade(1.0f - t, s->transition_b_mul);
+}
+
+static bool stinger_audio_render(void *data, uint64_t *ts_out,
+		struct obs_source_audio_mix *audio, uint32_t mixers,
+		size_t channels, size_t sample_rate)
+{
+	struct stinger_info *s = data;
+	uint64_t ts = 0;
+
+	if (!obs_source_audio_pending(s->media_source)) {
+		ts = obs_source_get_audio_timestamp(s->media_source);
+		if (!ts)
+			return false;
+	}
+
+	bool success = obs_transition_audio_render(s->source, ts_out,
+		audio, mixers, channels, sample_rate, mix_a, mix_b);
+	if (!ts)
+		return success;
+
+	if (!*ts_out || ts < *ts_out)
+		*ts_out = ts;
+
+	struct obs_source_audio_mix child_audio;
+	obs_source_get_audio_mix(s->media_source, &child_audio);
+
+	for (size_t mix = 0; mix < MAX_AUDIO_MIXES; mix++) {
+		if ((mixers & (1 << mix)) == 0)
+			continue;
+
+		for (size_t ch = 0; ch < channels; ch++) {
+			register float *out = audio->output[mix].data[ch];
+			register float *in = child_audio.output[mix].data[ch];
+			register float *end = in + AUDIO_OUTPUT_FRAMES;
+
+			while (in < end)
+				*(out++) += *(in++);
+		}
+	}
+
+	return true;
+}
+
+static void stinger_transition_start(void *data)
+{
+	struct stinger_info *s = data;
+
+	if (s->media_source) {
+		calldata_t cd = {0};
+
+		proc_handler_t *ph =
+			obs_source_get_proc_handler(s->media_source);
+
+		if (s->transitioning) {
+			proc_handler_call(ph, "restart", &cd);
+			return;
+		}
+
+		proc_handler_call(ph, "get_duration", &cd);
+
+		s->duration_ns = (uint64_t)calldata_int(&cd, "duration");
+
+		s->transition_point = (float)(
+			(long double)s->transition_point_ns /
+			(long double)s->duration_ns);
+		if (s->transition_point > 1.0f)
+			s->transition_point = 1.0f;
+		else if (s->transition_point < 0.001f)
+			s->transition_point = 0.001f;
+
+		s->transition_a_mul = (1.0f / s->transition_point);
+		s->transition_b_mul = (1.0f / (1.0f - s->transition_point));
+
+		obs_transition_enable_fixed(s->source, true,
+				(uint32_t)(s->duration_ns / 1000000));
+
+		calldata_free(&cd);
+
+		obs_source_add_active_child(s->source, s->media_source);
+	}
+
+	s->transitioning = true;
+}
+
+static void stinger_transition_stop(void *data)
+{
+	struct stinger_info *s = data;
+
+	if (s->media_source)
+		obs_source_remove_active_child(s->source, s->media_source);
+
+	s->transitioning = false;
+}
+
+static void stinger_enum_active_sources(void *data,
+		obs_source_enum_proc_t enum_callback, void *param)
+{
+	struct stinger_info *s = data;
+	if (s->media_source && s->transitioning)
+		enum_callback(s->source, s->media_source, param);
+}
+
+static void stinger_enum_all_sources(void *data,
+		obs_source_enum_proc_t enum_callback, void *param)
+{
+	struct stinger_info *s = data;
+	if (s->media_source)
+		enum_callback(s->source, s->media_source, param);
+}
+
+#define FILE_FILTER \
+	"Video Files (*.mp4 *.ts *.mov *.wmv *.flv *.mkv *.avi *.gif *.webm);;"
+
+static obs_properties_t *stinger_properties(void *data)
+{
+	obs_properties_t *ppts = obs_properties_create();
+
+	obs_properties_set_flags(ppts, OBS_PROPERTIES_DEFER_UPDATE);
+
+	obs_properties_add_path(ppts, "path",
+			obs_module_text("VideoFile"),
+			OBS_PATH_FILE,
+			FILE_FILTER, NULL);
+	obs_properties_add_int(ppts, "transition_point",
+			obs_module_text("TransitionPoint"),
+			0, 120000, 1);
+
+	UNUSED_PARAMETER(data);
+	return ppts;
+}
+
+struct obs_source_info stinger_transition = {
+	.id = "stinger_transition",
+	.type = OBS_SOURCE_TYPE_TRANSITION,
+	.get_name = stinger_get_name,
+	.create = stinger_create,
+	.destroy = stinger_destroy,
+	.update = stinger_update,
+	.video_render = stinger_video_render,
+	.audio_render = stinger_audio_render,
+	.get_properties = stinger_properties,
+	.enum_active_sources = stinger_enum_active_sources,
+	.enum_all_sources = stinger_enum_all_sources,
+	.transition_start = stinger_transition_start,
+	.transition_stop = stinger_transition_stop
+};