what's the avisynth deinterlace alternative for ffdshow's ?

[cobalt]

Hi,

I have been converting a really old VHS tape to .avi
However there are extremely irritating duplicate lines which seem like pure interlaced artifact.

I've been analysing the file with MeGUI which said I should use Yadif, the resulting file was EVEN WORSE !!!
I've been trying every single deinterlace method in ffdshow, and I finally found one which works quite well.
In ffdshow, it's the one called "5-tap lowpass" with "Process whole image" checked, and also "Process frames flagged as progressive" checked, "Swap fields" NOT checked.

Now, I really would like to reconvert this .avi to .avi using avisynth filter that does exactly what ffdshow's "5-tap lowpass" deinterlacer does, so I can put the file on USB stick and play on ps3.

Does anyone know if there is a proper identical filter for avisynth that does exactly what the "5-tap lowpass" deinterlacer does in ffdshow please ?

Thanks a lot !

[jagabo]

ffdshow's 5-tap deinterlacer is something like Blur(1.0) in AviSynth. Maybe Blur(0,1.0). All of them will make frames blurry and look like double exposures when there's lots of motion.

If Yadif() didn't work well your video may be screwed up. Post a short sample of the source.

[cobalt]

Thank you for trying to help jagabo, Yadif() really made it much worse (it's that one MeGUI proposed after analyzing my file).

I'm not too talented, which tool is the easiest to create a short sample please ? The file is an .avi .
Should I use Virtualdub, i don't know MeGUI can just 'cut' a part from it, it always wants to re-encode ?
Which processing option should I choose when using VirtualDub ?

Thanks, but I'm really newbie.

[jagabo]

To create a short sample with VirtualDub:

1) File -> Open Video Files (select your AVI)
2) Video -> Direct Stream Copy
3) Audio -> No Audio (optional)
4) Use the Mark-in and Mark-out tools (right-most tools, look like arrows) to mark the start and end if the segment you want to save. Holding down a shift key while navigating will stop only keyframes where the cuts will be made (Direct Stream Copy only cuts on keyframes).
5) Files -> Save as AVI

A 10 second sample with significant motion should be enough.

Another thing you can try: open your file with VirtualDub. Add the Bob Doubler filter. Step through a section of video with significant motion. Do you see any comb artifacts or frames that look like double exposures in the output window?

[cobalt]

Thank you very much for the great help jagabo,

I'll post a small sample in a couple of minutes.

[cobalt]

Here is a small sample (5MB, 16 sec)
http://www.megaupload.com/?d=VISU1DI1

Using the Bob Doubler filter also makes the results much worse than the original.

[loekverhees]

Yeah, your video is screwed up. It is not an interlaced video, but it is progressive. In the process of making an XVID of the movie, no deinterlacing is applied. It will be hard, if not impossible, to fix this XVID. Do you have the original interlaced source?

[jagabo]

Loekverhees is correct. That video started out as 25 fps interlaced PAL but was improperly resized and converted to 29.97 fps NTSC. As a result the two fields are no longer separate, they have been mixed together, and every sixth frame is a duplicate. You need to go back to the original PAL video, if you can.

[cobalt]

Thanks for all the help, unfortunately I don't own any VHS recorder anymore.
I don't even remember what program I used in that time to convert it to .avi

Guess I'll have to live with it, it getting some avisynth filter which does like the ffdshow 5-tap deinterlacer does.

[jagabo]

Guess I'll have to live with it, it getting some avisynth filter which does like the ffdshow 5-tap deinterlacer does.

Try Blur(0, 1.0) followed by Sharpen(0, 0.7). That looks almost exactly the same as ffdshow's 5-tap. Use less sharpen if you want fewer comb artifacts -- at the cost of a blurrier picture.

With a normal interlaced video Blur(0, 1.0) will completely eliminate comb artifacts. Following that with Sharpen(0, 0.7) will restore most of the sharpness to horizontal edges without restoring the comb artifacts. Using higher sharpen values will get more of the sharpness back but will start producing over-sharpening ringing artifacts.

[poisondeathray]

If you use DirectShowSource() and ffdshow set as the decoder for you video, you can use ffdshow's deinterlacer (or any of ffdshow's filters), and it should pass through to your encode

[jagabo]

If you use DirectShowSource() and ffdshow set as the decoder for you video, you can use ffdshow's deinterlacer (or any of ffdshow's filters), and it should pass through to your encode

I should have mentioned that. That's exactly what I was doing to compare ffdshow to blur/sharpen.

And if you use AviSource() you should enable ffdshow's VFW decoders instead.

[cobalt]

Thank you very much for the help everyone !
Blur() and Sharpen() work great.