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Old 29th February 2016, 10:44   #819  |  Link
r0lZ
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Join Date: Jul 2003
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There are two AR stored in the final MKV. The Sample Aspect Ratio (SAR, stored in the h264 video stream) and the Picture Aspect Ratio (called above DAR, because I don't like PAR, meaning Pixel Aspect Ratio, but DAR stricto sensu is the aspect ratio of the display device.) The Picture AR is stored in the header of the MKV container. The player can use the SAR or the Picture AR, in conjunction with the PAR or DAR of the device to compute the way it should display (stretch) the picture.

Furthermore, some players use another information to deduce the correct aspect ratio: the Stereoscopy method (SBS, T&B...), itself stored in the h264 stream (the --frame-packing argument of the x264 command) and in the MKV header (the stereoscopy field), and even in the file name (if you have selected one of the Output File Name -> 3D Format Extension setting and your player recognises it.) Again, the player can use any information it can handle, and unfortunately, most players are not 3D-aware at all, and ignore the SBS or T&B format. And some players, notably most 3D TVs, assume that a 3D movie is always in 16:9, regardless of the width, height and aspect ratios.

As you can see, the subject is complex, and I have never found a reliable doc on the correct aspect ratios to use for SBS and T&B combined frame. I don't know if it's the aspect ratio of the combined 3D source, or the aspect ratio of the target 3D frames that matters. Originally, the AR used by BD3D2MK3D was always 16:9, even in Full-SBS/T&B, but after a discussion with zaphodalive, I have decided to add the option in the Settings menu. (That discussions starts in the last paragraph of this post.) At that time, I was almost sure that 16:9 was correct, and I have only implemented an hidden option to change it. But later, when I did more tests, I have noticed that indeed, most players need 32:9 for Full-SBS and 16:18 for Full-T&B, and therefore that it's the source AR that must be specified. Unfortunately, it's not the case of all players. And I'm still not sure for the SAR. Anyway, I have added the option to control the Picture AR in the Settings menu in v0.60, but there is still no option to control the SAR.

So, if changing the Picture AR in the Settings does not change anything for you, that means probably that your player does not takes it into account, and uses the SAR only. May I know what player you use? Personally, I use PotPlayer to watch the movie in 2D on PC, and the player of my Samsung TV to watch it in 3D. PotPlayer recognises the "3D-LRQ" extension of the file names to know that the movie is in Half-SBS (and "3D-LR" for full SBS), and you can configure it easily to show either the left or right frame only, with the correct output aspect ratio, and optionally the correct half of the 3D subtitles or the 2D subtitles in 2D. My TV, as most 3D TVs, stretches the decoded image to occupy the whole 16:9 screen anyway, and ignores absolutely everything else, including the subtitles.

As far as I know, the SAR used by BD3D2MK3D is correct, and I don't think I'll change it. Your way to watch the movie in 2D by zooming on a single frame is very specific, and I don't think it should determine the SAR. But again, I may be wrong, and if someone can prove that 1:1 is the correct SAR for Full-SBS and Full-T&B, I'll change it, or I'll add a new option to control it. In the meantime, is it sufficient for you to edit __ENCODE_3D.cmd?
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BD3D2MK3D A tool to convert 3D blu-rays to SBS, T&B or FS MKV

Last edited by r0lZ; 29th February 2016 at 10:55.
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