Problems with Histogram/Tweak and Other Teething Problems

I'm having trouble with Histogram. At first, I tried to load the plugin, but that generated an error message telling me that the plugin was already loaded, at which point I realized that it is now built in. So I removed the call to LoadPlugin(), but I now receive an error message saying that there is no function called hist.

I took the code from the usage section of Histogram.

core.std.hist.Color2(video)

Apologies for the newb question! I installed VapourSynth only yesterday and am trying to teach myself VapourSynth and basic Python at the same time. (I'm much more used to AviSynth's way of doing things.)

[Are_]

It's core.hist.Color2(video)

[Selur]

Try core.hist.Color(...) without the 'std',... (Are_ was faster )

Thank you both! That works. I'm still uncertain about when to use std or core and when not to. Moreover, the documentation says that it's possible to chain filters with a dot (like AviSynth), but I'm receiving error messages when I do so.

[Selur]

Sorry, never tried that. I usually don't chain filters in Avisynth either.

[Are_]

Every plugin should start with the core, but once it is there you can't call it again in the same call.

Then the namespace of the plugin follows it, it is like the container of all functions the plugin has. That's what you usually see like std, resize, hist...

And after that, you call the function you want from that plugin, Color2 for example.

clip = core.resize.Bicubic(clip, 640, 480)
clip = core.hist.Color2(clip)

becomes

clip = core.resize.Bicubic(clip, 640, 480).hist.Color2(clip)

The downside about this is it can get ugly pretty fast and if you get errors it makes them harder to track down.

Ofc to create the core there are many methods, you can use

from vapoursynth import core

which is ugly and prone to produce shit code or the good old

import vapoursynth as vs
core = vs.get_core()

That being said the ugly way is quite good for short scripts.

Originally Posted by Selur

Sorry, never tried that. I usually don't chain filters in Avisynth either.

Oh, I see. Is there a technical reason for that or is it just preference?

Originally Posted by Are_

Every plugin should start with the core, but once it is there you can't call it again in the same call.

Then the namespace of the plugin follows it, it is like the container of all functions the plugin has. That's what you usually see like std, resize, hist...

And after that, you call the function you want from that plugin, Color2 for example.

clip = core.resize.Bicubic(clip, 640, 480)
clip = core.hist.Color2(clip)

becomes

clip = core.resize.Bicubic(clip, 640, 480).hist.Color2(clip)

The downside about this is it can get ugly pretty fast and if you get errors it makes them harder to track down.

Thanks for the explanation! Yeah, the latter example that you posted looks like what I'm used to doing in AviSynth.

Originally Posted by Are_

Ofc to create the core there are many methods, you can use

from vapoursynth import core

which is ugly and prone to produce shit code or the good old

import vapoursynth as vs
core = vs.get_core()

That being said the ugly way is quite good for short scripts.

I'm really glad that you posted this. I've been seeing the two ways of doing it all over place and wondered which was right or whether they were linked to different versions of Python or whatever. I started by following the documentation, which uses the new way, but after what you've said, I think that I might use the old way. In fact, my current script has a mix of the two because some functions refer to vs, which in the new way remains undefined.

[hBIkOa7m]

Originally Posted by Are_

clip = core.resize.Bicubic(clip, 640, 480).hist.Color2(clip)

The downside about this is it can get ugly pretty fast and if you get errors it makes them harder to track down.

It seems to be quite common that people writing filter code make absolutely no effort to format their code in a way that makes it maintainable or readable. Even if you're only running the script as a one-off job, I've never understood why people make it harder for themselves.

You can chain methods AND use new lines - if you make each line only do one job errors are much easier to track down. By wrapping the block in parenthesis you can newline as much as you like. This is the preferred way in Python. Some MWE:

import vapoursynth as vs
core = vs.get_core()

clip = (core.std.BlankClip()
            .resize.Bicubic(1280, 720)
            .text.ClipInfo()
            .std.Turn180()
       )

clip.set_output()

You can also just escape the newlines with a backslash. I think this is more ugly than parenthesis.

import vapoursynth as vs
core = vs.get_core()

clip = core.std.BlankClip() \
           .resize.Bicubic(1280, 720) \
           .text.ClipInfo() \
           .std.Turn180()

clip.set_output()

You should line up your indentation on the dots.

^ The second option looks like the way I do things in AviSynth, although I tab the backspaces to make them line up and look a little neater. I'll try the first in VapourSynth. It does look more elegant.

EDIT: I now have a problem with Tweak().

import adjust

video2 = core.adjust.Tweak(video,hue=XX)

The result is an error.

ModuleNotFoundError: No module named "adjust"

The documentation says:

Drop adjust.py someplace where Python can find it, then use import adjust in your scripts.

I don't know where Python can find adjust.py. I tried putting it in the same directory as the script, but obviously that's the wrong thing to do.

The documentation has a Plugin Autoloading section, but it doesn't seem to refer to .py files, and I'd prefer to load things manually anyway, at least for the time being.

[poisondeathray]

Originally Posted by Richard1485

I don't know where Python can find adjust.py. I tried putting it in the same directory as the script, but obviously that's the wrong thing to do.

I place .py in the python => lib => site-packages directory . Then you can import it with "import adjust"

Another useful .py is HAvsFunc.py by HolyWu - it has many familiar avisynth functions
https://forum.doom9.org/showthread.php?t=166582

(PS. when I come across "std", I take penicillin )

Thanks! Unfortunately, that generates a syntax error that points to line 7 of adjust.py itself, possibly because it was written with an older version of Python in mind. I'm using 3.64 with the latest 64-bit version of VapourSynth.

Originally Posted by poisondeathray

(PS. when I come across "std", I take penicillin )

That's probably wise.

[poisondeathray]

Originally Posted by Richard1485

Thanks! Unfortunately, that generates a syntax error that points to line 7 of adjust.py itself, possibly because it was written with an older version of Python in mind. I'm using 3.64 with the latest 64-bit version of VapourSynth.

I don't even have a line 7. It's blank.

I think I'm using this one
https://forum.doom9.org/showthread.php?t=172808

^ With that version, renamed to adjust.py, I receive a different error.

AttributeError: No attribute with the name adjust exists. Did you mistype a plugin namespace?

[poisondeathray]

Weird, it works here

I'm using it like this

import vapoursynth as vs
import adjust
core = vs.get_core()
#clip = whateversourcefilter()
clip = adjust.Tweak(clip, sat=0.5)
clip.set_output()

Got it! I removed core before adjust.Tweak() and moved import adjust so it came before core = vs.get_core(), and it's working. I think the VapourSynth port of Tweak() works like SmoothTweak() in AviSynth in that when one adjusts hue it shifts the chroma in a linear fashion along an axis. With the original Tweak(), I could rotate/turn the chroma like turning a key in a lock.

[poisondeathray]

Yes, the one in that post separated U, V hue like smoothtweak .

I only added separate settings for hue v and u (idea taken from SmoothTweak plugin).

The original one by dubhater is more like classic tweak

In that case, I wish I could get the original one to work, but it doesn't. Maybe it's meant for 32-bit VapourSynth; I'm using the 64-bit version.

EDIT: It's a shame that one cannot have both approaches to hue. The ability to rotate the chroma is useful, in my opinion.

[poisondeathray]

Originally Posted by Richard1485

In that case, I wish I could get the original one to work, but it doesn't. Maybe it's meant for 32-bit VapourSynth; I'm using the 64-bit version.

EDIT: It's a shame that one cannot have both approaches to hue. The ability to rotate the chroma is useful, in my opinion.

It works the same way, you can just drop it in and replace

If you want to use both at the same time, just rename one (e.g adjust2.py) and use a different namespace e.g import adjust2 as adjust2

import vapoursynth as vs
import adjust
import adjust2 as adjust2
core = vs.get_core()
#clip = whateversourcefilter()
clip = adjust.Tweak(clip, hue=20)
clip = adjust2.Tweak(clip, huev=10)
clip.set_output()

[DJATOM]

> import adjust2 as adjust2
that is redundant
import adjust2 will be the same

[Selur]

Oh, I see. Is there a technical reason for that or is it just preference?

Mainly: readability and easier debugging.