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Old 25th August 2014, 12:18   #68  |  Link
r0lZ
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BD3D2MK3D v0.45

Important bug fix for 3D subtitles

Thalyn has discovered that the BD3D2MK3D method to apply the 3D depth extracted from the 3D-planes was wrong. (See here.) The depth value extracted from the 3d-plane was correct (and the error was not related to the frames skipped at the beginning or end of the subtitle as suggested here), but I have used a wrong method to apply the depth to the original 2D subtitles.

When a subtitle is in front of the screen (with a positive depth value), the subtitle of the left view must be shifted to the right, and the subtitle of the right view must be shifted to the left. It's exactly the opposite when the depth is negative and the subtitle appears behind the screen.

In the previous versions of BD3D2MK3D, I have wrongly assumed that the number of pixels to use for the shift was the absolute value of the depth divided by 2 for each view. With that formula, the difference (in pixels) between the two pixels was exactly the depth value. But that was wrong. The number of pixels to use is the depth value for each view, and the total difference is therefore the depth value multiplied by 2. The effect of the bug was that the subtitles appeared too close to the screen that it should.

With the new version of BD3D2MK3D, the values saved in the <Depth> tags of the temporary 2D XML file are now the depth values from the 3D-planes multiplied by 2, so that the result of the conversion to 3D is now correct. As a consequence, all <Depth> tags are now even numbers (but if you edit them manually, you can use odd depth values, if you need more precision.)

That means that you should redo the conversion of your 3D subtitles if you want correct depths. Sorry for that! Note that you should not convert a XML file with <Depth> tags already inserted by a previous version without using the 3D-plane, as the wrong depth values will be retrieved from the XML and not computed with the right formula.

Thanks to Thalyn for the discovery of that important bug, and for the numerous tests he did to confirm that the current method is the right one! Since I don't have a 3D graphic card, I was unable to do that tests myself (hence the origin of the bug).

(BTW, his tests have also confirmed that PowerDVD has also a bug with the placement of the 3D subtitles, systematically off by 2 pixels.)
Quote:
# v0.45 (August 25, 2014)
# - Fix: The formula to compute the depth value extracted from the 3D-Planes was wrong. (Thanks Thalyn)
Download: BD3D2MK3D.7z
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Last edited by r0lZ; 25th August 2014 at 12:20.
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