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| septimus |
| Posted: Apr 20 2008, 04:28 AM |
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Member
Group: Members
Posts: 28
Member No.: 22608
Joined: 13-December 07
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fccHandler,
I have some .M2V files captured from a Canon XH-A1 (MPEG2ES, direct-to-disk).
Windows Media Player sees them as 1920x1080
Intervideo WinDVD sees them as 1920x1080
VirtualDub 1.7.8 and version 2.4 of the plugin pull them up as 1440x1080
I'm pretty sure they're supposed to be 1920x1080. Any idea as to what's going on? |
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| Placio74 |
| Posted: Apr 20 2008, 05:07 AM |
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VideoAudio
Group: Members
Posts: 1216
Member No.: 21485
Joined: 24-May 07
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Hmm... just anamorphic?
http://www.thedigitalbits.com/articles/anamorphic/
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VideoAudio.pl - Serwis o technologii wideo & audio |
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| septimus |
| Posted: Apr 20 2008, 04:03 PM |
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Member
Group: Members
Posts: 28
Member No.: 22608
Joined: 13-December 07
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I think I've figured some of this out...
The M2V files are in fact 1440x1080, so there is no bug in the plugin (my apologies
to fccHandler).
What I don't quite understand is why WMP and WinDVD say they are 1920x1080
-- is there some upsampling to 'full HD' from HDV going on in the decoder? |
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| IanB |
| Posted: Apr 20 2008, 10:11 PM |
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Avisynth Team Member
Group: Members
Posts: 121
Member No.: 22295
Joined: 23-October 07
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The M2V's video stream obviously has a 16:9 display aspect ratio setting. So display proceedures are required to output a 16:9 picture. To do this correctly we need to know the aspect ratio of the display device pixels.
If the display pixels are square, like on a PC screen, and the display window needs to be 16:9, then some rescaling has to happen. Most windows media players choose to upscale the short dimension so as not to loose display quality. The decoded souce image is as you say, 1440x1080, so to get a 16:9 image the player calculates the required width, 1920=1080*16/9. Equally it could have downscaled vertically, 810=1440*9/16, but this would result in a lose of image detail.
When processing video we generally do not want the decoded source image reprocessed, we want to do the reprocessing. We want to make the choice of how to rescale the image, if we rescale it at all. You may choose to encode it to another format that also has an option to set the display aspect ratio property. |
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