Avisynth Help thread

[TGBatman]

Originally Posted by Scab

It flags the pixel aspect ratio of your clip which stays the same no matter how you've cropped it.

So, does this means that even if I crop whatever number of pixels at each side of the image (staying mod16 of course), 8640/4739 for 16:9 or 6480/4739 for 4:3 stays like that?

And, what if I need to crop 4 pixels in Y, but not in -Y? 476 is not mod16, the next mod16 number would be 464 I think, and that's too much crop. I have one of those.

Again, thanks for the help and sorry for so much questions.

[Scab]

8640/4739 and 6480/4739 are DAR numbers. IIRC the SAR for 4:3 NTSC is 10/11 (704*(10/11)=640) and 40/33 for 16:9. And yes, those stay the same as long as you don't resize.

If you can't crop to mod16 you either overcrop (good) or resize (bad; watch the AR error %). If you feel adventurous I suppose you could crop to a non-mod16 resolution; x264 can handle it just fine but playback results may be unpredictable.

[TGBatman]

Well, I'd like to stay mod16. I guess it depends on the case, sometimes overcropping might be a good idea, sometimes not. Guess I can't have the Holy Grail huh.

Thanks for the help guys, have a nice day.

[Zergrinch]

This may sound like a retarded question, but bear with me. I'm still inexperienced

I'm in the process of ripping a DVD with meGUI, which is in 720x480 resolution.

I want to merge this with AviSynth to a video that's in 640x480 resolution.

Question - do I need to resize the video to match the DVD [e.g. Lanczos4Resize(720,480) ] or can I just merge as is? Suppose I don't merge, but use ordered chapters in Matroska instead - will that change the answer?

I ask with the understanding that meGUI automatically passes on an aspect ratio to x264, telling it to dynamically use 4:3 (or 640x480 resolution) for the NTSC DVD.

Thanks in advance

[jfs]

Zergrinch, read the discussion that has JUST been had in this very thread, it's an AR issue you're having.

@TGBatman: Nobody cares about the outer 16 pixels on either edge of the picture, the animation is generally made to take overscan into account and thus there won't be any interesting picture that near to the edges, you can safely just crop 8 pixels at every edge and not resize at all. (Or only crop at left/right edges if the picture touches the top and bottom perfectly all the way through; but it's ugly if some sections have small black pixel lines near the top or bottom, IMO.)

[Zergrinch]

I did read it, and my decision was to rip the DVD as is and let the --sar option take care of aspect ratios.

But I'm looking for something slightly different. I want to get a 720x480 set to 4:3 AR to play with a 640x480 set to 1:1. Can I do that or do I have to resize said 640x480 first?

[jfs]

No if you have multiple segments with different pixel resolutions you must make them all have the same pixel resolution.

[Kristen]

Recently, about 1/8 h.264 encode come out for me with fine video and audio to start with. But at a select point in the encode, the video will change to the following screen:
http://i27.tinypic.com/2ignojm.jpg
And it will remain that way for the rest of the encode.

My avisynth script is usually:

AVISource("C:\Lossless.avi")
Textsub("C:\subs.ass")

And when I run the encode a second time without changing anything, it encodes perfectly.

Does anyone know what's going wrong so I don't have to waste 3-6 hours?

[TGBatman]

@jfs

That's good to know, I'll try to crop 8 pixels from each side next time, as long as I don't lose important detail and stay mod16, I'm ok with it.

[SHiN-gx]

Originally Posted by K!R4

I thought gradfun2db sole purpose is for post processing (during playback), not for preprocessing (encode) because this filter wont work unless you have a higher bitrate for your encode.

To see what Im talking about: encode your video with this filter then once its done play it on mediaplayer classic. While its playing, check ffdshow video decoder below your right taskbar (there are two of these: the red and blue icons) right click the red one, it will list some filters. you will see gradfun and it has check mark, heres a interesting part of this filter: turn off gradfun and you will see the real outcome of your encode. Either your encode will look shit (banding are back on your encode) or your encode will look good because you have higher bitrate you used in your encode to compensate.

Figured that. Well, I need some tips on how to remove the banding in my encodes. Here's a different sample:

Original:

Spoiler for Screenshot:

With Tweak() and Levels() in Preview:

Spoiler for Screenshot:

Original's quality is not so good. You can still see banding and it became worse if I add in Tweak and Levels. I'm looking for a filter to remove or lessen the banding.

Thanks.

[fireshark]

...it's called gradfun2db. Or try gradfunkmirror if that suits you. either way you have to throw more bitrate at it or it's not going to help no matter how much gradfun you do.

[SHiN-gx]

Originally Posted by fireshark

...it's called gradfun2db. Or try gradfunkmirror if that suits you. either way you have to throw more bitrate at it or it's not going to help no matter how much gradfun you do.

Already did that but it's for post-processing only. I want to actually remove the banding in my encodes.

[TheFluff]

it works exactly the same when encoding as it does when postprocessing, the problem is to get the encoder to keep the nice smooth gradients and not re-introduce the banding; usually this is only a problem in dark scenes

one solution is to add a very small amount of grain (think addgrainc(1.0) or even less) and encode with a small amount of psy-rd.

[TheFluff]

Originally Posted by Kristen

Recently, about 1/8 h.264 encode come out for me with fine video and audio to start with. But at a select point in the encode, the video will change to the following screen:
http://i27.tinypic.com/2ignojm.jpg
And it will remain that way for the rest of the encode.

My avisynth script is usually:

AVISource("C:\Lossless.avi")
Textsub("C:\subs.ass")

And when I run the encode a second time without changing anything, it encodes perfectly.

Does anyone know what's going wrong so I don't have to waste 3-6 hours?

Odd issue, especially since it's not reliably reproducible, but the general solution to odd Avisynth crashes is to empty out the plugin autoload directory and only leave the dll's that ship with Avisynth in there, and load the plugins you need manually instead.

[andy_blah]

I am having again the same blended frames problem as I previously explained here, the only difference now is that this is from the actual interlaced source (DVD). I tried a few deinterlacers such as Yadif, TDeint, TempGaussMC, LeakKernelDeint, all with correct settings, and all seem to produce those blending artefacts. Is there any solution for this problem? If needed I can give some samples of the source.

[jfs]

First tell what it looks like if you SeparateFields() and otherwise do not process the source at all. Do the individual fields contain blending? If so, it's impossible to save.

[andy_blah]

Originally Posted by jfs

do not process the source at all

By this, you mean to not include any filters?

Tried it anyways and it seems that unfortunately the blending is still there

[Raislin]

This might be a rather broad question. I'm trying to collect myself a number of quality plugins for AviSynth and I'm wondering what some people here would consider essentials.

Ha, I phrased my question as a statement. Anyways, suggestions are welcome of course. I'm not really in a rush, though, because I'm lacking some anime sources to work with at the moment.

[jfs]

Originally Posted by andy_blah

By this, you mean to not include any filters?

Tried it anyways and it seems that unfortunately the blending is still there

Yes, following this idea for the complete Avisynth script:

mpeg2source("myfile.d2v")
separatefields()

(Switch mpeg2source for whatever the actual source filter you use is.)

If you see blending in that, your source is impossible to fix, except with ten thousand hours in mspaint.

[andy_blah]

Tried without any filters as you suggested above, and unfortunately the blended artefacts are still there. But then again it is fortunate that the DVD doesn't have this problem all the time ^_^

Originally Posted by jfs

If you see blending in that, your source is impossible to fix, except with ten thousand hours in mspaint.

Haha, yes, I can imagine that, would be a pain for the PC, and a even greater pain for me