compositor: Skip background if transparent and obscured

If the background is transparent and obscured by a pad that may or may
not have alpha, we can still skip drawing it entirely

AYUV 1080p ! compositor background=transparent ! fakesink - 75% faster
This commit is contained in:
Nirbheek Chauhan 2019-05-26 17:47:20 +02:00
parent ba20aec539
commit ba4484c6a0

View file

@ -314,7 +314,7 @@ clamp_rectangle (gint x, gint y, gint w, gint h, gint outer_width,
/* Call this with the lock taken */
static gboolean
_pad_obscures_rectangle (GstVideoAggregator * vagg, GstVideoAggregatorPad * pad,
GstVideoRectangle rect)
GstVideoRectangle rect, gboolean rect_transparent)
{
GstVideoRectangle pad_rect;
GstCompositorPad *cpad = GST_COMPOSITOR_PAD (pad);
@ -325,8 +325,10 @@ _pad_obscures_rectangle (GstVideoAggregator * vagg, GstVideoAggregatorPad * pad,
/* Can't obscure if it's transparent and if the format has an alpha component
* we'd have to inspect every pixel to know if the frame is opaque, so assume
* it doesn't obscure. */
if (cpad->alpha != 1.0 || GST_VIDEO_INFO_HAS_ALPHA (&pad->info))
* it doesn't obscure. As a bonus, if the rectangle is fully transparent, we
* can also obscure it if we have alpha components on the pad */
if (!rect_transparent &&
(cpad->alpha != 1.0 || GST_VIDEO_INFO_HAS_ALPHA (&pad->info)))
return FALSE;
pad_rect.x = cpad->xpos;
@ -393,7 +395,7 @@ gst_compositor_pad_prepare_frame (GstVideoAggregatorPad * pad,
* higher-zorder frames */
l = g_list_find (GST_ELEMENT (vagg)->sinkpads, pad)->next;
for (; l; l = l->next) {
if (_pad_obscures_rectangle (vagg, l->data, frame_rect)) {
if (_pad_obscures_rectangle (vagg, l->data, frame_rect, FALSE)) {
frame_obscured = TRUE;
break;
}
@ -837,7 +839,7 @@ _negotiated_caps (GstAggregator * agg, GstCaps * caps)
}
static gboolean
_should_draw_background (GstVideoAggregator * vagg)
_should_draw_background (GstVideoAggregator * vagg, gboolean bg_transparent)
{
GstVideoRectangle bg_rect;
gboolean draw = TRUE;
@ -849,7 +851,7 @@ _should_draw_background (GstVideoAggregator * vagg)
/* Check if the background is completely obscured by a pad
* TODO: Also skip if it's obscured by a combination of pads */
for (GList * l = GST_ELEMENT (vagg)->sinkpads; l; l = l->next) {
if (_pad_obscures_rectangle (vagg, l->data, bg_rect)) {
if (_pad_obscures_rectangle (vagg, l->data, bg_rect, bg_transparent)) {
draw = FALSE;
break;
}
@ -865,8 +867,11 @@ _draw_background (GstVideoAggregator * vagg, GstVideoFrame * outframe)
BlendFunction composite = comp->blend;
/* If one of the frames to be composited completely obscures the background,
* don't bother drawing the background at all. */
if (!_should_draw_background (vagg))
* don't bother drawing the background at all. We can also always use the
* 'blend' BlendFunction in that case because it only changes if we have to
* overlay on top of a transparent background. */
if (!_should_draw_background (vagg,
comp->background == COMPOSITOR_BACKGROUND_TRANSPARENT))
return composite;
switch (comp->background) {