Fix issues when ungrouping meta changes the final sequencer render

Seems to be caused by the way how the most bottom strip in the stack
used to apply effect. Just rendering strip in this cases will not give
proper results.

Made it so effect is applying between empty imbuf and actual strip.
Seems to work by tests, but more intense testing is required.

1 files changed, 7 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/sequencer.c b/source/blender/blenkernel/intern/sequencer.c
index 6185f8de9d7..a1cd6b87a05 100644
--- a/source/blender/blenkernel/intern/sequencer.c
+++ b/source/blender/blenkernel/intern/sequencer.c
@@ -3028,7 +3028,13 @@ static ImBuf *seq_render_strip_stack(const SeqRenderData *context, ListBase *seq
 				break;
 			case EARLY_DO_EFFECT:
 				if (i == 0) {
-					out = seq_render_strip(context, seq, cfra);
+					ImBuf *ibuf1 = IMB_allocImBuf(context->rectx, context->recty, 32, IB_rect);
+					ImBuf *ibuf2 = seq_render_strip(context, seq, cfra);
+
+					out = seq_render_strip_stack_apply_effect(context, seq, cfra, ibuf1, ibuf2);
+
+					IMB_freeImBuf(ibuf1);
+					IMB_freeImBuf(ibuf2);
 				}
 
 				break;