N00b question: Is re-encoding useless?Need some advice....

[DavidHazelnut]

Hi peeps,

I pick up an Xvid here and there and i am not always pleased with the quality, so i have some questions about this issue. The quality is fine on SD or analog televisions but not so great on LCD HD flat screens, so excuse me the quality is not good for those screens.

I always stream my vids through XBMC (Xbox media player), the Xbox is connected to my HD LCD television via component cable. Most of the vids look great especially 2cd rips, but there are a lot xvids that have pixelation/artifacts in them, and other vids look great and have almost none?

I let XBMC upscale video files to 720p and every single detail is visible, and that means that artifacts/pixelation is more visible.

XBMC does not play HD files at 720p because the hardware is not powerful enough, nor am i interested in getting those big HD files. But my question is this:"Is re-encoding useful if the source is average?'. Can i actually apply filters and tricks to make an average Xvid look like an great quality Xvid?

I know jack about Avisynth and i'm no expert in using Vdubmod or Vdub, but i use Vdubmod sometimes to correct out of sync sound... Avisynth is unknown territory for me and it seems hard to use, although i think i used it a long time ago to create a KVCD (if i typed it correctly).

I've tried some filters and re-encoding with Vdubmod but i end up with worst quality, so it seems almost impossible to do.....

So can you guys and gals give a N00b some advice on how to do this? (If it's useful of course)

Cheers,

David

[redwudz]

I let XBMC upscale video files to 720p and every single detail is visible, and that means that artifacts/pixelation is more visible.

Yes, you will almost always see that. You can't really make the quality better. But you can filter out a bit of the blockiness and correct the color and contrast and maybe remove some noise. But you will also have quality loss just from the re-encoding. Worth it? Probably not. But give it a try. The MSU deblocking filter is one that comes to mind. http://www.compression.ru/video/deblocking/index_en.html

Or lots of VD filters at: http://www.thedeemon.com/VirtualDubFilters/

I would make up a short clip, maybe 5 - 10 minutes of a representative piece of one of your videos, run it through VD and try some filtering. Set your bitrate 10% or so higher than the original bitrate and see how it looks. The file will also end up larger, but you may minimize the quality loss that way. And you can try different settings, both filtering and bitrate to see if it's worth it for yourself.

If you find a good combination, then you should be able to duplicate it with AVIsynth and speed up the process and precision a fair amount.

And welcome to our forums.

[DavidHazelnut]

Thank you for welcoming me, and thank you for your advice! But i'm a complete N00b to Avisynth....Is there an easy way to use it?

Cheers,

David

[redwudz]

I'm a newbie with AVIsynth, though I understand basically how it works. Probably a good place to start is the AVIsynth website: http://avisynth.org/mediawiki/Main_Page

There should be tutorials and guides you can access there. We have a fair amount of members that use it extensively and should be able to answer specific questions if you get 'stuck'.

The nice thing about AVIsynth, is that once you have a good script that does what you want for your video file, you can use it over again with a new file, or make minor modifications to adjust it.

[Midzuki]

redwudz wrote:

Probably a good place to start is the AVIsynth website:
http://avisynth.org/mediawiki/Main_Page

Not at all. http://avisynth.org.ru/docs/english/ is much better.

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