Flicker Filter?

[Yo]

If the input video has a lot of flickering, from poor VHS video, etc. are there filters one can use in Vdub or vdubmod to improve the video?

What about the noise, temporal filters, etc.? Good settings for those?

[Tommy B.]

Try the deflicker filter

http://www.compression.ru/video/deflicker/index_en.html

[Yo]

Originally posted by Tommy B.
Try the deflicker filter

http://www.compression.ru/video/deflicker/index_en.html

Tried it, and it made Vdub crash.

[Tommy B.]

I used it with vesion... 1.5.7 I think. Never used it again since there was no need. Maybe you should try 1.5.7.

[Yo]

Originally posted by Tommy B.
I used it with vesion... 1.5.7 I think. Never used it again since there was no need. Maybe you should try 1.5.7.

The version I used was the newest. Just downloaded a couple days ago. I don't recall seeing multiple versions to choose from.

Did it really take out flicker? What settings did you use?

[Tommy B.]

I can't tell you since this was a while ago.

Anyway. Took a look into my plugins folder of VD 1.5.10 and found a deflicker filter by Donald Graft. Since I can't reach his page anymore (it's offline), I zipped the msu file and the help file and uploaded it to my host.

http://www.twogun.de/deflicker10dgraft.zip

As I recall there was also a flickering video in the package but I don't have it anymore. What I can say is that the filter is quite good, except it sometimes creates way to bright scenes when there are cuts.

Oh and don't forget to read the help file or you might miss that this filter runs in 2 passes.

[Leak]

Originally posted by Tommy B.
Anyway. Took a look into my plugins folder of VD 1.5.10 and found a deflicker filter by Donald Graft. Since I can't reach his page anymore (it's offline), I zipped the msu file and the help file and uploaded it to my host.

Errr... I'm quite positive that Don's page isn't offline, as I was just browsing his forum minutes ago:

http://neuron2.net/flick.html (oh yeah, there's a 1.1 version there too...)

:D

np: Andreas Tilliander - Track 10 (Ljud)

[Tommy B.]

Ah yes. Seems like google led me to a dead place :D

[Fizick]

Alternative:
http://forum.doom9.org/showthread.php?s=&threadid=77487

[Yo]

In looking at the readme.txt file that comes with the Graft Deflicker filter, there is something uunusual (to my eyes, at least) about its implementation.

According to the txt file, first you have to "prepare" the video, by choosing "prepare video", and play through the whole video, from beginning to end, in real time, in Vdub, before encoding. Then you have to go back to the configure filter box, and choose "Process Video". Then, after previewing that, you can go ahead and encode.

A long addition to the time it takes to create the movie, if it is a full size movie, 2 hours or so, besides the encoding time!

Did I misread something in that file? Do any other filters require such a "prepare" step of playing through the whole movie?

It really better do an excellent job of "deflickering" to be worth that! Anyone here used it?

[Tommy B.]

It is required. Since the source has to be analyzed so the brightnes can be adjusted/corrected. There is nothing you can do about it.

As I said, there might be some errors on scene changes where the picture might light up a little bit too much but this might have been fixed in 1.1

[Yo]

Originally posted by Tommy B.
It is required. Since the source has to be analyzed so the brightnes can be adjusted/corrected. There is nothing you can do about it.

As I said, there might be some errors on scene changes where the picture might light up a little bit too much but this might have been fixed in 1.1

In my previous note I wrote that you have to play through the movie in "real time". It's actually much worse than that. It goes much slower than real time. It took close to 4 hours to go through a 1:45 hour movie, in that "prepare" mode.

In that "prepare" mode, the output screen is blacked out, as is stated in the txt file. However, after the movie has played through, and one reconfigures the filter for "process", the output screen was still blacked out. I could not preview the output video. Why?

Then, when I tried to "Save Avi", after a couple seconds it aborted, with the following error message:

Virtual Dub Error

Cannot Start Video Compression:

The Source Image Format is Not acceptable,
(error code -2)

What does that mean? The source video is MPEG-2. I am using VirtualDubMod, which reads that video.

I had DIVX 5.2 set up as the video compressor.

Thinking that the deflicker filter might be causing the problem, I deleted the filter. Immediately the output screen showed up again, so I figured the deflick filter must be causing the problem. However, on "Save AVI" I got the same result, same error message.

What does that error message mean?

Why wasn't I able to see the output preview after choosing "Process Video" in the deflicker filter?

If I decided to add the deflicker filter again, would I have to play the movie through again in "Prepare Video mode", another four hours to "prepare" the filter? Or has it saved the results of its scan of that movie somewhere?

[Tommy B.]

1. The results of the scanned movie might be saved in your computers RAM so it might be possible that it won't remember the 1st pass once you close VirtualDub. This depends on the memory management of Windows I guess.

2. It should be possible to run a first pass in realtime, with 25 fps or less. Set "audio" to "No Audio" and deactivate all other filters you have selected. They must be eating up resources and thus slow down the whole process. You can leave the resize filter in though. This one isn't that intensive.

3. I think the video has to be prepared once it can be played back (so the filter runs through the frames one more time and calculates something). This is just speculation though. If you set the filter to "process video" it should display the picture...

4. Check your video's width and height. If it's not divideable by 32, you just might get this error.

[Yo]

Well, have people got good results with this deflick filter. Does it really take out flicker? Any bad effects of it?

I don't really understand the settings. Would the default settings work well for most flicker?

Is it good to use any other filters in addition (or instead of) for flickering old video--like smoother and/or temporal smoother, chroma smoother, etc. Would any of these help with flicker as well?

Thank you.

[Tommy B.]

Well, have people got good results with this deflick filter. Does it really take out flicker? Any bad effects of it?
As I said, there were flashes during scene changes. But you can try to deflicker the demonstration file which is available at D. Graft's page (link below).

I don't really understand the settings. Would the default settings work well for most flicker?
Click the "help" button and read the readme. I think that's what it is for.

Window size: This is the size of the moving average of frame luminance values.
This produces the luminance value that frames are adjusted to. The idea is that
you want it as small as possible while still removing flicker. Ideally, it is equal to
the number of frames that one flicker peirod spans. For example, if the video
frame rate is 25 fps and the flicker is at 7 fps (example of 18 fps shot at 25 fps;
25 -18 = 7), then one flicker period is 25/7 = 3.57 frames. We want our window
to exactly cover an integral number of flicker cycles. So a good choice here would
be a window size of 7 (~ 2 * 3.57). You can always set a long window size if in
doubt, but doing so will spread out luminance changes in the clip. A window size
of 25 is a good general-purpose compromise.

Softening: This is the threshold for the final temporal softening phase. Often, the
physical process that creates the flicker also creates within-frame illumination changes,
causing adjacent frames to differ. This softening phase greatly reduces this effect.
A higher number causes greater temporal softening but can leave motion trails. If the
physical process does not produce within-frame changes, this phase can be disabled
by setting the softening to 0.


If you want to get the best settings by trying, cut out a small sample of your movie (about 2 minutes long) and try the deflicker filter. Thus you won't need to run through the hole movie.

Is it good to use any other filters in addition (or instead of) for flickering old video--like smoother and/or temporal smoother, chroma smoother, etc. Would any of these help with flicker as well?
I don't think so. If you place the filters before deflicker, they might fuck up the whole picture. But as usually, try it yourself.

[Yo]

Originally posted by Tommy B.

Click the "help" button and read the readme. I think that's what it is for.

If you place the filters before deflicker, they might fuck up the whole picture. But as usually, try it yourself.

I did read the readme, that you posted. (I read it even before installing, from the zip file. That's how I knew about the "prepare" procedure.) Just that I don't understand it. I'm a newbie at this, reading that really doesn't give me any clue as to how to set the settings. Again, are the default values good for fixing most flickering video?

If I did as you suggest, and take a tiny piece of the video, and try it with the default values, and am not completely satisfied with the results, what changes in the settings would you suggest I use for the second try?

Regarding the second paragraph above, is the order you place filters in Vdub important? I didn't know that. They get processed in the order they are placed? Would the no filters placed before deflick rule also apply to a resize filter?

Best not to use "smoother" filters with deflick?

It sounds like you have used this filter. Have you had good results with it? Worth all the extra processing time?

[Tommy B.]

It is best if you don't use any filters at all, at least during the
first pass. The filters are applied in the order they appear (which
means the ones on the bottom will be the last). You may use the
resize filter though, since it won't impact on the speed of the
whole process that much (compared to any other more complicated
filters like soften or sharpen).

Yes, I used the filter. And as I said (and I do it one more time),
the results were not that satisfying since on scene changes the whole
picture became very bright (as stated in your other thread using
the MSU Deflicker filter). I don't why it is this way, maybe cause
both filters use the same code.