1. Preface

The basic rule is that you have to insert a logo removal filter as soon as possible. Every filter applied before any editing done (except trimming and deinterlacing) will make your results significantly worser. Also the general opinion in the doom9 forum is that, if you captured to anything except Huffyuv or MJPEG above 18 there's no sense in using a filter either.

2. Virtualdub usage

In Virtualdub you will have to insert the filter right after using the deinterlacer. Go again to Video > Filters > Add and choose one of the three above mentioned filters. In the window that pops up now, specifiy the position and the size of the logo. This is more or less a trial and error process. What you can do is to make a screenshot of one of your frames, import it into your favourite grapics program (not M$ Paint etc please), and some mesuring there. To finetune your settings you'll have to use the preview window though! Some important points:

• The main difference between Xlogo/Delogo and Logoway: Logoaway can handle the case when your logo is partially located in the black bars.
• For Xlogo and Delogo you will also have to provide a screenshot of your logo.
• In Logoaway you can specifiy the method and strength in which the logo is blurred away!

3. AviSynth v2.0x / AviSynth v2.5x / GordianKnot Usage

3.1 Dekafka

Import("e:\dekafka.avsi")

at the beginning of your script. Note that this filter will convert the clip and the maskclip to the colorformat RGB32, since this is the only format with an alpha channel (at least in all versions up to AviSynth v2.52). You should remove the logo after deinterlacing. We have chosen here to do it before any resizing. But if you want it to do after resizing, remember to make the mask of the logo after resizing.

creating a mask file
After deinterlacing your script looks like (for example) the following:

Import("e:\dekafka.avsi")
AviSource("d:\capture.avi")
Trim(begin, end)
Telecide()

Open this script in VirtualdubMod, select "video" and "copy source frame to clipboard" (choose a frame where the logo is clearly visible). Import it into your favourite grapics program (for example using Corel photo-paint: "File" -> "New From Clipboard"). Cut the logo to a new document (for example using Corel photo-paint: draw a box with "Rectangular Mask Tool" -> "Copy" -> "Paste As New Document"), in such a way that the logo is surrounded (on all four sizes) by at least four pixels of the clip (enlarge your clip if necessary):

This results in:

Make the logo while (including one pixel of the clip surrounding the logo), and the surrounding pixels black:

You have two options: make a avi-movie from it (for example using Corel photo-paint: "Movie" -> "Create From Document") or save it as a BMP/JPEG/PNG. Turn on the script-editor of VirtualdubMod and load your mask:

1) If you made a movie of your mask, your script becomes for example (the filter Loop is used here to make the maskclip of the same length as your clip):

Import("e:\pdwork\dekafka.avsi")
clip = AviSource("e:\pdwork\DO-Heaven.avi")
clip = Telecide(clip)
maskclip = AviSource("e:\pdwork\mask.avi")
Loop(maskclip, Framecount(clip))

2) If you made a picture of your mask, your script becomes for example (we used the filter ImageReader here to read the image, if you are using AviSynth v2.0x you have to use the plugin "ImageWriter"). The filter Loop is used here to make the maskclip of the same length as your clip:

Import("e:\pdwork\dekafka.avsi")
clip = AviSource("e:\pdwork\DO-Heaven.avi")
clip = Telecide(clip)
maskclip = ImageReader("e:\pdwork\mask.jpg", 0, 0)
maskclip = FlipVertical(maskclip)  # This is necessary when DevIL is reading the picture instead of AviSynth internal BMP-parser.
Loop(maskclip, Framecount(clip))

adjusting your AviSynth script
Next, add the dekafka logo removal filter. The general syntax is given by:

dekafka(clip clip, clip maskclip, int Xstart, int Ystart, int X, int Y, int Amount)

(Xstart, Ystart) is the left corner of the mask. Remember that the X-axis is runs from left to right and the Y-axis from top to bottom. "X" is the width and "Y" the height of the masklogo. Finally, "Amount" is the amount of blend between the clip and the masklogo (with amount=0 you will see the clip itself, with amount=256 you will see the masklogo and in between the clip and masklogo will be blend). Set it to 128 first, otherwise you might not see the masklogo :) Our logo is in the right upper corner, so we start at the position (Xstart, Ystart) = (500, 2):

Import("e:\pdwork\dekafka.avsi")
clip = AviSource("e:\pdwork\DO-Heaven.avi")
clip = Telecide(clip)
maskclip = ImageReader("e:\pdwork\mask.jpg", 0, 0)
maskclip = FlipVertical(maskclip)  # This is necessary when DevIL is reading the picture instead of AviSynth internal BMP-parser.
maskclip = Loop(maskclip, Framecount(clip))
dekafka(clip, maskclip, 500, 2, maskclip.width, maskclip.height, 256)

Scroll slowely through the frames till you see the masklogo (that can be a tough job :)):

If you found the masklogo, change the the position (Xstart, Ystart) till the positions of the masklogo and logo coincide:

Import("e:\pdwork\dekafka.avsi")
clip = AviSource("e:\pdwork\DO-Heaven.AVI")
clip = Telecide(clip)
maskclip = ImageReader("e:\pdwork\mask.jpg", 0, 0)
maskclip = FlipVertical(maskclip)  # This is necessary when DevIL is reading the picture instead of AviSynth internal BMP-parser.
maskclip = Loop(maskclip, Framecount(clip))
dekafka(clip, maskclip, 550, 48, maskclip.width, maskclip.height, 256)

At last, you can try to lower the "Amount" for a better result (if your logo is white, as in our case, you might leave it as "256").

3.2 Xlogo

But IF you decide to use AviSynth v2.5x and feel up to the task of manually specifiying the parameters in your AviSynth script, here's what you will have to add to your script:

Where all the other plugins are loaded:
LoadPlugin("c:\yourplugindir\xlogo.dll")

After deinterlacing:
Xlogo(Clip, filename, X, Y, ALPHA, T1, T2, T3, B1, B2, B3, WHITE, SIDE, SCENE, FEATHER, NOISE)

Here's how a complete configured Xlogo command could look like:

AviSource("e:\pdwork\atomic.avi")
Telecide()  # or some other deinterlace method
Xlogo("e:\guides\000000.bmp", 530, 38, 0)  # Xlogo converts internally to RGB32

Afterwards proceed as described in the AviSynth post processing guide.

4. Download and documentation links

Here are a few links to forum discussions:
doom9.org forum discussion 1
doom9.org forum discussion 2
doom9.org forum discussion 3

Generally it is always a good idea to lurk around in the forum to get the latest news.

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Last edited on: 09/07/2003 | First release: n/a | Authors: SteVe (killingspree) & Wilbert | Content by doom9.org