Doom9's Forum - View Single Post - Which is better

Vilx- · 14th August 2016, 09:47

I'm slowly in the process of moving my DVD collection to my hard drive, re-encoding them with x264 in the process to save space (tools used - DVDDecrypter and MeGUI; target container - MKV). I have no problems, but recently something struck me as perhaps being wrong.

As part of the process I also resample the movies to have a 1:1 pixel aspect ratio. Because... well, it kinda seems right. Everything uses square pixels these days, after all. To do that, I use the default setting of MeGUI, which downscales the picture. However I recently tried to compare the resampled picture with the original, and found that there was a noticeable increase of bluriness - which makes sense, of course.

So, to combat that I did the math myself and tried upscaling instead, which produced a picture much closer to the original (I wasn't able to tell the difference). Pretty good, although, of course, upscaling (theoretically) adds its own bluriness in the direction of the stretch. And it takes up more space. And MeGUI for some reason doesn't allow to set these numbers in the GUI, I have to edit the AviSynth script by hand. I presume there must be some good reason for this...

And then there's the third option, which I haven't tried yet - don't resample anything, but just set the appropriate flags on the container, so that the player does all the resampling at the time of playback. It'll have to upscale the picture anyway, after all, since all display devices these days have a higher resolution than a DVD, so I skip an extra resampling. I assume this can be done, but as I said - I haven't tried it yet, so maybe I'm wrong. Plus, I suspect that there might be compatibility issues with players, and that it might not be possible to specify the exact target aspect ratio (after all, even for a 4:3 PAL DVD, the 4:3 applies to the center 704 pixels, not the entire 720 pixels).

So... I'm confused - which approach should I use and why?

14th August 2016, 09:47	#1 \| Link
Vilx- Registered User Join Date: May 2011 Posts: 28	Which is better - upscaling, downscaling or no scaling? I'm slowly in the process of moving my DVD collection to my hard drive, re-encoding them with x264 in the process to save space (tools used - DVDDecrypter and MeGUI; target container - MKV). I have no problems, but recently something struck me as perhaps being wrong. As part of the process I also resample the movies to have a 1:1 pixel aspect ratio. Because... well, it kinda seems right. Everything uses square pixels these days, after all. To do that, I use the default setting of MeGUI, which downscales the picture. However I recently tried to compare the resampled picture with the original, and found that there was a noticeable increase of bluriness - which makes sense, of course. So, to combat that I did the math myself and tried upscaling instead, which produced a picture much closer to the original (I wasn't able to tell the difference). Pretty good, although, of course, upscaling (theoretically) adds its own bluriness in the direction of the stretch. And it takes up more space. And MeGUI for some reason doesn't allow to set these numbers in the GUI, I have to edit the AviSynth script by hand. I presume there must be some good reason for this... And then there's the third option, which I haven't tried yet - don't resample anything, but just set the appropriate flags on the container, so that the player does all the resampling at the time of playback. It'll have to upscale the picture anyway, after all, since all display devices these days have a higher resolution than a DVD, so I skip an extra resampling. I assume this can be done, but as I said - I haven't tried it yet, so maybe I'm wrong. Plus, I suspect that there might be compatibility issues with players, and that it might not be possible to specify the exact target aspect ratio (after all, even for a 4:3 PAL DVD, the 4:3 applies to the center 704 pixels, not the entire 720 pixels). So... I'm confused - which approach should I use and why? Last edited by Vilx-; 14th August 2016 at 14:24.