[video sequence editor] Offset and crop of strips are wrong #34013

New Issue

Jehan Pagès · 2013-01-27T21:01:33+01:00

Jehan Pagès commented

2013-01-27 21:01:33 +01:00

%%%Hi,

bug happening on the dev version (svn): setting offset or crop value gets completely wrong rendering. See bug_transform.png
As you can see from the image, here is the procedure:

I have a simple image bla.png, and I offset it of 200px.
check you have a 100% resolution.
check the actual offset. In my example, that's 100px.

Crops also have the same issue (the crops are completely different from the expected value).
See transform_bug.blend (though it is extremely easy to reproduce anyway).

The reason is that in source/blender/blenkernel/intern/sequencer.c: input_preprocess(), there is this strange code, which scales the crop or offset depending on the strip image size:
xscale /= (double)context.rectx / (double)ibuf->x;
yscale /= (double)context.recty / (double)ibuf->y;

This is wrong, and anyway even removing only this lines is not good either, because any scaling is wrong at this state as actual scaling is done later (so if you actually scale, you get double scaling of your transformation).
Then I saw I was basically reverting commit 52629 (which itself was reverting 50901, with this additional logics of scaling depending on image buffer dimensions).

So I checked this bug report #33295 (for which commit 52629 has been done), and looked at the bug.
Basically the bug in #33295 was because color strips are "preprocessed" strips (already at the scaled size). So in this case only you want to pre-scale the offsets and the crops (and they won't be scaled a second time because the finale render is already the right size as well in preprocessed strip case).

So the attached patch transform_bug.diff fixes both the current issue and the one from #33295 as you can see from my blend file and from the blend file in this other ticket.%%%

%%%Hi, bug happening on the dev version (svn): setting offset or crop value gets completely wrong rendering. See bug_transform.png As you can see from the image, here is the procedure: * I have a simple image bla.png, and I offset it of 200px. * check you have a 100% resolution. * check the actual offset. In my example, that's 100px. Crops also have the same issue (the crops are completely different from the expected value). See transform_bug.blend (though it is extremely easy to reproduce anyway). The reason is that in source/blender/blenkernel/intern/sequencer.c: input_preprocess(), there is this strange code, which scales the crop or offset depending on the strip image size: xscale /= (double)context.rectx / (double)ibuf->x; yscale /= (double)context.recty / (double)ibuf->y; This is wrong, and anyway even removing only this lines is not good either, because any scaling is wrong at this state as actual scaling is done later (so if you actually scale, you get double scaling of your transformation). Then I saw I was basically reverting commit 52629 (which itself was reverting 50901, with this additional logics of scaling depending on image buffer dimensions). So I checked this bug report #33295 (for which commit 52629 has been done), and looked at the bug. Basically the bug in #33295 was because color strips are "preprocessed" strips (already at the scaled size). So in *this case only* you want to pre-scale the offsets and the crops (and they won't be scaled a second time because the finale render is already the right size as well in preprocessed strip case). So the attached patch transform_bug.diff fixes both the current issue and the one from #33295 as you can see from my blend file and from the blend file in this other ticket.%%%

Jehan Pagès commented

2013-01-27 21:01:33 +01:00

Changed status to: 'Open'

Jehan Pagès commented

2013-01-31 07:32:39 +01:00

%%%I attach a new version of the patch, transform_bug_v2.diff.
That's basically the same with a small fix (happening only with preprocessed sequences with crop only (no transform), and also a nicer code (more systematic).%%%

%%%I attach a new version of the patch, transform_bug_v2.diff. That's basically the same with a small fix (happening only with preprocessed sequences with crop only (no transform), and also a nicer code (more systematic).%%%

Peter Schlaile commented

2013-02-10 22:04:09 +01:00

%%%confirmed the issue and the patch is now in SVN.

Closing this now.

Thanks for the thorough investigation and the patch!

Regards
Peter%%%

%%%confirmed the issue and the patch is now in SVN. Closing this now. Thanks for the thorough investigation and the patch! Regards Peter%%%

Peter Schlaile commented

2013-02-10 22:04:09 +01:00

Changed status from 'Open' to: 'Resolved'

Peter Schlaile closed this issue

2013-02-10 22:04:09 +01:00

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[video sequence editor] Offset and crop of strips are wrong #34013