Advantages of using AVISynth?

[Strakha]

I know AVISynth is capable of more than simply frameserving; it's also capable of inserting filters.

What I want to know, is why bother? Why not just insert the same filters using VirtualDub?

I used to use GKnot, but now presumably for the DivX 5.03 codec I can't. For converting a DVD to divx 5.03 I would:

1. Rip the vob files (obviously)
2. Use DVD2AVI then VPAFI to allow VirtualDub to access the video stream
3. Graphedit to rip the audio
4. Finally use virtualdub to compress the audio and video streams, and add whatever filters I wanted.

Cheers :confused:

[manono]

Hi and welcome to the forum.

Are you asking us or telling us? I didn't know anyone still frameserved with a VFAPI. If you don't like the extra speed afforded by frame serving with an .avs and using Fast Recompress, instead of the slower Full Processing and the quality degrading RGB Color Conversion (slight though it may be), then keep on doing it the way that suits you best.

You can still use the .avs and set up VDub manually.

[TelemachusMH]

Most people use avisynth because it allows very flexable filtering, which is also faster, and higher quality then Vdub. It is faster because it doesn't need to convert the videos into RGB colorspace, this is also the cause of the quality lose. Also avisynth is able to split video into chunks (Movie and credits for instance) and filter them seperatly without making many files. Avisynth is a very powerfull program that lets you edit pretty much anyway you want, and because of the frameserving can be used with any program that uses avi files.

TelemachusMH

[Strakha]

I wasn't telling you I was asking, really! I'm only just beginning to get to grips with the more advanced side of encoding, so I just thought I'd explain the way I would do it without GKnot so you could point out any errors.

I just used VPAFI because it's easy, but now I want to get the best quality I can out of my rips. VPAFI was what I used before I discovered GKnot, and although I know how to use GKnot I don't know how it all works. I assume it incorporates AVISynth into in somewhere.

So basically what you are saying is that frameserving with AVISynth is better because it doesn't do the RGB colour conversion (does that mean is does YUV or something?). Even if the quality difference is only slight, then I'd like to do it anyway.

Fast recompress - I didn't know what that was for until now. Does this mean that you are able to set the compression parameters within the AVISynth script? I suppose it must seeing as you are able to load the scripts into divx5enc to conduct compressibility tests.

Before I just did the compression tests within Gnot, but another thing that got me wondering about AVISynth was the program AVSCompare. It got me thinking about different filters such as sharpen or blur etc.. Are those sorts of filters used, or is it simply the resize and null transform ones?

Making an AVISynth script for DivX 5.03 sounds hard. What I really need is an AVISynth guide :(

Thanks for helping a poor soul :)

[TelemachusMH]

I just used VPAFI because it's easy, but now I want to get the best quality I can out of my rips. VPAFI was what I used before I discovered GKnot, and although I know how to use GKnot I don't know how it all works. I assume it incorporates AVISynth into in somewhere.

GordianKnot creates an avisynth script, when you click save or save and encode. Most of the options you setup with GordianKnot are put into the script. (It doesn't save the audio or codec specific information)

So basically what you are saying is that frameserving with AVISynth is better because it doesn't do the RGB colour conversion (does that mean is does YUV or something?). Even if the quality difference is only slight, then I'd like to do it anyway.

Yes, the YUV -> RGB color convertion is what causes most of the quality lose there. I am not sure about this, but I think I remember reading that divx and xvid store the video in YUV so the video would have to be converted back from RGB to YUV for storing.

Fast recompress - I didn't know what that was for until now. Does this mean that you are able to set the compression parameters within the AVISynth script? I suppose it must seeing as you are able to load the scripts into divx5enc to conduct compressibility tests.

Fast recompress bypasses VirtualDub's filtering process, so the color convertion (and any filters that are set) will not be used. Basicly what you put into virtualdub will be compressed by the codec.

Before I just did the compression tests within Gnot, but another thing that got me wondering about AVISynth was the program AVSCompare. It got me thinking about different filters such as sharpen or blur etc.. Are those sorts of filters used, or is it simply the resize and null transform ones?

In GordianKnot you can put in smoothing filters but there aren't any sharpening filters. However there actually are many more smoothers and sharpeners for AviSynth, GordianKnot just doesn't have support for them.

Making an AVISynth script for DivX 5.03 sounds hard. What I really need is an AVISynth guide

It actually isn't that hard, it is a pretty simple scripting language all you really need to know if the Manual (http://avisynth.org/index.php?page=AviSynthManual) and people will help you if you ask too.

TelemachusMH

[jorel]

manono wrote:
"Are you asking us or telling us?"
:p :p ;)
and:
" I didn't know anyone still ...then keep on doing it the way that suits you best.
You can still use the .avs and set up VDub manually."
i learn more than Strakha!

TelemachusMH wrote in the first post:
"Most people use avisynth because it allows very flexable filtering, which ... and because of the frameserving can be used with any program that uses avi files."

;) very good explanations.;)
and in the second post too!!!

ps :
@ TelemachusMH
Just a kid at heart...;) fantastic words!

[manono]

Hey-

If I sounded harsh at first, it was because of this:

What I want to know, is why bother?

which implied, to me, that you were familiar with both methods and found no differences between the two. Read everything on the site that Telemachus linked to. AviSynth is your Bible. But you don't really need much knowledge of how it works in order to use it. Use GKnot for cropping and resizing, getting the bit rate and the .avs generation. Then learn which filters are built into AviSynth 2.07 and what they do, and you only have to add the command to your script by editing it either within GKnot, or later on. And learn which filters are available as Plugins where you'll have throw the .dll in the GKnot folder and both load the Plugin and add the command to the script. I'd also recommend cutting out the lines in the GKnot generated .avs script that begin with "#" so you can see more easily the lines that really do something.

Thanks to TelemachusMH for explaining it well.
Thanks to jorel for providing some humor. :)

[jorel]

manono
:)
in a few more words,
you explain more than i learn in months!
every night,i stay here and see many people like you that,
when wants to teach,open the wise brain and with simple words
turn clear my(our) minds.
thank you!;)

[Strakha]

Don't worry Manono, I'm not that sensitive! :) I said "Why bother" because I didn't understand and I wanted someone to put me straight, that's all. I sometimes unintentionally come across as arrogant, but if I thought I understood things I wouldn't be posting in the newbie forum.

Thanks to everyone for your help. I'll give this encoding a go with AVISynth, and would be happy to accept your offer of helping out with the script when I get that far. BTW you might also want to explain what the hell Jorel is on about sometime, I don't think the google translation software is working right ;)

[jorel]

was wrote:
"...I'm not that sensitive! "
:rolleyes: really?

and:
"I sometimes unintentionally come across as arrogant,..."
really!:p

ps:
don't need BTW or a google translation software to feel it!
;)

editing:
i forgot:
and wrote too:
"... a poor soul "
:eek:

[Strakha]

Forget about AVISynth, I think understanding you Jorel is much harder ;)

Cheers guys. I'm going to try ripping and encoding "The Untouchables", I'll RTFM and post back if I get stuck with AVISynth.

[jorel]

Originally posted by Strakha
Forget about AVISynth, I think understanding you Jorel is much harder ;)

Cheers guys. I'm going to try ripping and encoding "The Untouchables", I'll RTFM and post back if I get stuck with AVISynth.

sorry,i'm only kidding(too bad)....is my poor english of course.
don't want to bore you,ok?

...friends???
:)

editing:
ps:
your post have a very good question
and i came here to read the answers about this.
:)

[Strakha]

That's quite alright Jorel, I was only kidding too. :cool: