Large file after using filter in Virtualdub

[Jasen]

Hello,
first thank´s for a very informative site.
It has helped a lot and also increased my interest for transfer vhs to dvd
I do have some questions that i wonder if you please could give me help me with.
When capturing i use Virtualdub as capture software and i am selecting Huffyuv as format.
The vhs in question is just 15 minutes long and when done capturing the result is a file of 6,68GB.
If i reopen this file and apply the Neat Video filter and "save as avi" after filtering, the
file is 26,7 GB large which is quite a big change in size. But i guess i should select huffyuv
when saving after filtering as well? Or should i first capture to avi format, open file and apply filter and
when ready filtering "save as avi" and huffyuv?
Regards Jasen

[premiumcapture]

By default, VirtualDub will not compress an opened file when saving. In order to keep in Huffy, you do need to reselct it under 'compression' to resave to the smaller filesize. If your file is already captured in Huffyuv, save any edits back to Huffyuv.

[sanlyn]

Premiumcapture has it right. If you open a YUY2 AVI in VirtualDub and apply filters (most of VDub's filters work in RGB32), by default VirtualDub saves the output as uncompressed RGB. So click "Video..." -> "color depth.." and set output to YUY2. Then click "Video..." -> "compression..." and set huffyuv for YUY2.

[Jasen]

Thank´s for the reply premiumcapture.
I suspected that it might be the way to do it but i thought it might be best to ask just to be sure.
Thank´s again.
Regards Jasen

Thank you sanlyn.
I didn´t know the "Video..." -> "color depth.." and set output to YUY2" feature.
Great advice,thank´s.
Regards Jasen

[TylerDurden389]

I haven't started my project yet, but I know this advice is gonna help me out. Thanks guys!!

[premiumcapture]

A very key point from Sanlyn that I should not have forgotten to mention. Without getting too technical, RGB and YUV are two different ways of expressing color, RGB for digital and YUV for analog video. One is not better than the other and the most important decision for which color space to use is what the source was created in and which format its going to. VHS should stay in YUV or a variant like YUY2.

[dpalomaki]

To expand a bit, RBG color tends to be used in computer graphics and displays (e.g., the monitor's screen).

YUV is used for video signals; or more specifically variants on YUV - YCbCr for digital video, and YPbPr for analog video.

The YUV model was adopted decades ago to save bandwidth and retain compatability with B&W TV signals.

Conversion between the color spaces can result in artifacts if not done correctly because the math behind it can result in "negative" values (which makes no sense), values greater than 1 (blown out), and depending on bit depth may result in banding. That is one reason why we may encounter color shifts when video is moved to/from different editing/filtering programs.

[Jasen]

Thank you all for the input.
I have now redone the filtering process and saved the file using huffyuv as
compression and the YUY2 option as output in color depth.
The result is a file that is 6,44GB compared to the unfiltered file that is 6,68GB.
Visually the filtered file looks better than the original as well i think and no new artifacts
as far as i can see so it all work well.
Thank´s again for the help.
Regards Jasen.

[sanlyn]

Quote:

Originally Posted by premiumcapture

A very key point from Sanlyn that I should not have forgotten to mention. Without getting too technical, RGB and YUV are two different ways of expressing color, RGB for digital and YUV for analog video. One is not better than the other and the most important decision for which color space to use is what the source was created in and which format its going to. VHS should stay in YUV or a variant like YUY2.

RGB=digital and YUV=analog? A mis-typing, maybe? DV and DV-AVI, lest we forget, are always YUV. DVD, BluRay, AVCHD, DivX, XVid, etc., are all digital formats and all are stored as YUV (YV12, mostly). VHS (analog) is stored as YCbCr, the nearest counterpart for common capturing use being YUY2. Component video (analog) is YPbPr.

RGB and YUV are indeed two different color systems, each having their pros and cons, each being in common use all over the planet, and each having its specific use and purpose. By the way, we humans can't see YUV, nor can our eyes see digital 0's and 1's. That's why display devices designed to be viewed by humans -- whether the display is CRT, LCD, plasma, projector, etc. -- are ultimately analog RGB devices. Their output is light waves, which are analog phenomena.

[premiumcapture]

Quote:

Originally Posted by sanlyn

RGB=digital and YUV=analog? A mis-typing, maybe?

Quote:

Originally Posted by premiumcapture

Without getting too technical

I am of course, oversimplifying, but RGB pixels are represented by a numeric value which in theory and practice is more digital. YUV, YUY2, YCbCr, etc... are terms that discuss different aspects of the YUV color gamut, and historically, such as with the VCR, luma and chroma signals were transmitted and overlapped to form a complete picture. Clearly, as we see with Mpeg-2 and H.264, it is still used today in all-digital forms, but again, extreme oversimplifying.

http://en.wikipedia.org/wiki/Yuv
http://en.wikipedia.org/wiki/Rgb

[dpalomaki]

I believe in the context of the discussion, both RBG and YUV (or Pr/b or Cr/b) are means of encoding visual information. RBG captures the values of the primary red, green, and blue light as separate values. On the other hand, YUV values are obtain by applying a matrix to the RBG values to derive luminance (B&W) image and color difference (UV) information that can later be used to recreate (subject to limits) the original RBG image on a display. Neither is inherently digital and both came out of the days and world of analog video.

The main reasons for YUV were: backward compatability with B&W TV, and bandwidth savings by taking advantage of the fact that the human eye "sees" color with less resolution than B&W - at the cost of significantly more complex circuitry. Computer graphics tended ot be RBG because that is simpler and ther usually is no reason to convert to YUV is it never leaves the computer domain.

I believe that Video is still mainly YUV in part as legacy of the analog color video days, and in part to save bandwidth.

[lordsmurf]

I would be careful not to overfilter with NeatVideo, as most tend to do. Avisynth is better.
- Avisynth and VirtualDub are scalpels.
- NeatVideo is a meat clever.