VSE renders with alpha transparent PNG image incorrectly #52522

New Issue

Satoshi Yamasaki · 2017-08-24T04:04:32+02:00

Satoshi Yamasaki commented

2017-08-24 04:04:32 +02:00

System Information
Windows 10 Pro x64, GeForce GTX 1060 6GB

Blender Version
Broken: 2.79-7b397cd (RC2), 2.79 RC1
Worked: 2.78c

Short description of error
VSE renders incorrectly between a Scene strip and an Image strip which has a PNG file saved by Gimp with "Save background color" and "Save color values from transparent pixels" options.

Exact steps for others to reproduce the error

In VSE, insert a scene strip in channel 1
Insert an image strip in channel 2 and specify an image file that I mentioned above.
Set "Alpha Over" blend option of the image strip.
(Optional)Enable "Use Backdrop" option of VSE header.
Render with [F12]. You can see VSE doesn't render translucency of the image.

Or, You can download the attached file and test the blend file in it.

Thanks,
279VSEBug.zip

**System Information** Windows 10 Pro x64, GeForce GTX 1060 6GB **Blender Version** Broken: 2.79-7b397cd (RC2), 2.79 RC1 Worked: 2.78c **Short description of error** VSE renders incorrectly between a Scene strip and an Image strip which has a PNG file saved by Gimp with "Save background color" and "Save color values from transparent pixels" options. **Exact steps for others to reproduce the error** 1) In VSE, insert a scene strip in channel 1 2) Insert an image strip in channel 2 and specify an image file that I mentioned above. 3) Set "Alpha Over" blend option of the image strip. 4) (Optional)Enable "Use Backdrop" option of VSE header. 5) Render with [F12]. You can see VSE doesn't render translucency of the image. Or, You can download the attached file and test the blend file in it. Thanks, [279VSEBug.zip](https://archive.blender.org/developer/F723477/279VSEBug.zip)

Satoshi Yamasaki commented

2017-08-24 04:04:32 +02:00

Changed status to: 'Open'

Satoshi Yamasaki commented

2017-08-24 04:04:32 +02:00

Added subscriber: @SatoshiYamasaki

Bastien Montagne commented

2017-08-30 20:06:41 +02:00

Added subscribers: @Sergey, @mont29

Sergey Sharybin was assigned by Bastien Montagne

2017-08-30 20:06:41 +02:00

Bastien Montagne commented

2017-08-30 20:06:41 +02:00

The problems comes from render result having a float buffer of pixels, while PNG reading generates a byte buffer.

@Sergey iirc, you did the optimization of freeing byte pixel of a strip's result when it has float values? Not sure how to fix this, something like that sort of does the trick, though color space seems to be wrong, probably not the right fix:

diff --git a/source/blender/blenkernel/intern/sequencer.c b/source/blender/blenkernel/intern/sequencer.c
index 3a04bd79360..5b1f50a8027 100644
    - a/source/blender/blenkernel/intern/sequencer.c
+++ b/source/blender/blenkernel/intern/sequencer.c
@@ -3688,6 +3688,17 @@ static ImBuf *seq_render_strip_stack_apply_effect(const SeqRenderData *context,

  float facf = seq->blend_opacity / 100.0f;
  int swap_input = seq_must_swap_input_in_blend_mode(seq);

 
+       printf("%p, %p  ||  %p, %p\n", ibuf1->rect, ibuf2->rect, ibuf1->rect_float, ibuf2->rect_float);
+
+       if (ibuf1->rect_float != NULL && ibuf2->rect_float == NULL) {
+               IMB_float_from_rect(ibuf2);
+               imb_freerectImBuf(ibuf2);
+       }
+       else if (ibuf2->rect_float != NULL && ibuf1->rect_float == NULL) {
+               IMB_float_from_rect(ibuf1);
+               imb_freerectImBuf(ibuf1);
+       }
+

  if (swap_input) {
          if (sh.multithreaded)
                  out = seq_render_effect_execute_threaded(&sh, context, seq, cfra, facf, facf, ibuf2, ibuf1, NULL);

The problems comes from render result having a float buffer of pixels, while PNG reading generates a byte buffer. @Sergey iirc, you did the optimization of freeing byte pixel of a strip's result when it has float values? Not sure how to fix this, something like that sort of does the trick, though color space seems to be wrong, probably not the right fix: ```lang=diff diff --git a/source/blender/blenkernel/intern/sequencer.c b/source/blender/blenkernel/intern/sequencer.c index 3a04bd79360..5b1f50a8027 100644 - a/source/blender/blenkernel/intern/sequencer.c +++ b/source/blender/blenkernel/intern/sequencer.c @@ -3688,6 +3688,17 @@ static ImBuf *seq_render_strip_stack_apply_effect(const SeqRenderData *context, ``` float facf = seq->blend_opacity / 100.0f; int swap_input = seq_must_swap_input_in_blend_mode(seq); ``` + printf("%p, %p || %p, %p\n", ibuf1->rect, ibuf2->rect, ibuf1->rect_float, ibuf2->rect_float); + + if (ibuf1->rect_float != NULL && ibuf2->rect_float == NULL) { + IMB_float_from_rect(ibuf2); + imb_freerectImBuf(ibuf2); + } + else if (ibuf2->rect_float != NULL && ibuf1->rect_float == NULL) { + IMB_float_from_rect(ibuf1); + imb_freerectImBuf(ibuf1); + } + ``` if (swap_input) { if (sh.multithreaded) out = seq_render_effect_execute_threaded(&sh, context, seq, cfra, facf, facf, ibuf2, ibuf1, NULL); ```

James Monteath commented

2017-08-31 20:49:38 +02:00

Added subscriber: @ponderz