Fix #36124: VSE - Input Color option does not work for video files

Byte images and movies will now fully follow input color space.
Before this non-sRGB input colorspace for byte images and movies
behave really doggy (results in preview and final render were
totally different).

To prevent data loss, if byte image is set not stored in sequencer's
space it'll be internally converted to float buffer.

In theory some setups might be rendering a bit different now, but
new behavior is totally expected and someone used non-sRGB input
space for byte images/movies had Convert Float enabled anyway.

1 files changed, 31 insertions, 19 deletions

diff --git a/source/blender/blenkernel/intern/sequencer.c b/source/blender/blenkernel/intern/sequencer.c
index a2ebdae572d..a88818dedcd 100644
--- a/source/blender/blenkernel/intern/sequencer.c
+++ b/source/blender/blenkernel/intern/sequencer.c
@@ -417,33 +417,41 @@ void BKE_sequencer_editing_free(Scene *scene)
 
 static void sequencer_imbuf_assign_spaces(Scene *scene, ImBuf *ibuf)
 {
-	IMB_colormanagement_assign_float_colorspace(ibuf, scene->sequencer_colorspace_settings.name);
+	if (ibuf->rect_float) {
+		IMB_colormanagement_assign_float_colorspace(ibuf, scene->sequencer_colorspace_settings.name);
+	}
 }
 
 void BKE_sequencer_imbuf_to_sequencer_space(Scene *scene, ImBuf *ibuf, int make_float)
 {
 	const char *from_colorspace = IMB_colormanagement_role_colorspace_name_get(COLOR_ROLE_SCENE_LINEAR);
 	const char *to_colorspace = scene->sequencer_colorspace_settings.name;
+	const char *float_colorspace = IMB_colormanagement_get_float_colorspace(ibuf);
 
 	if (!ibuf->rect_float) {
-		if (make_float && ibuf->rect) {
-			/* when converting byte buffer to float in sequencer we need to make float
-			 * buffer be in sequencer's working space, which is currently only doable
-			 * from linear space.
-			 *
-			 */
-
-			/*
-			 * OCIO_TODO: would be nice to support direct single transform from byte to sequencer's
-			 */
-
-			IMB_float_from_rect(ibuf);
+		if (ibuf->rect) {
+			const char *byte_colorspace = IMB_colormanagement_get_rect_colorspace(ibuf);
+			if (make_float || !STREQ(to_colorspace, byte_colorspace)) {
+				/* If byte space is not in sequencer's working space, we deliver float color space,
+				 * this is to to prevent data loss.
+				 */
+
+				/* when converting byte buffer to float in sequencer we need to make float
+				 * buffer be in sequencer's working space, which is currently only doable
+				 * from linear space.
+				 */
+
+				/*
+				 * OCIO_TODO: would be nice to support direct single transform from byte to sequencer's
+				 */
+
+				IMB_float_from_rect(ibuf);
+			}
+			else {
+				return;
+			}
 		}
 		else {
-			/* if there's only byte buffer in image it's already in compositor's working space,
-			 * nothing to do here
-			 */
-
 			return;
 		}
 	}
@@ -452,8 +460,10 @@ void BKE_sequencer_imbuf_to_sequencer_space(Scene *scene, ImBuf *ibuf, int make_
 		if (ibuf->rect)
 			imb_freerectImBuf(ibuf);
 
-		IMB_colormanagement_transform_threaded(ibuf->rect_float, ibuf->x, ibuf->y, ibuf->channels,
-		                                       from_colorspace, to_colorspace, TRUE);
+		if (!STREQ(float_colorspace, to_colorspace)) {
+			IMB_colormanagement_transform_threaded(ibuf->rect_float, ibuf->x, ibuf->y, ibuf->channels,
+			                                       from_colorspace, to_colorspace, TRUE);
+		}
 	}
 }
 
@@ -2668,6 +2678,8 @@ static ImBuf *do_render_strip_uncached(SeqRenderData context, Sequence *seq, flo
 				                         seq->strip->proxy ? seq->strip->proxy->tc : IMB_TC_RECORD_RUN,
 				                         seq_rendersize_to_proxysize(context.preview_render_size));
 
+				BKE_sequencer_imbuf_to_sequencer_space(context.scene, ibuf, FALSE);
+
 				/* we don't need both (speed reasons)! */
 				if (ibuf && ibuf->rect_float && ibuf->rect)
 					imb_freerectImBuf(ibuf);