FAQ's

This page contains answers to common questions, along with some tips and tricks that we have found useful and presented here as questions.

1.) What is this TWAIN stuff good for ?

2.) Which applications support TWAIN ?

3.) Why doesn't this special application work ?

4.) What is the TWAIN protocol ?

5.) What is the difference to VfW ?

6.) I installed the TWAIN driver, but still don´t see the grabber as capture device, why ?

7.) What settings should I select during installation?

What is this TWAIN stuff good for ?

    Twain is an standard interface for applications to interface image and audio acquisition sources. This means, every image source, best known scanners, that has an TWAIN driver can communicate with any application, that supports this generic interface.

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Which applications support TWAIN ?

    Uups, this is not easy to answer (and because of the current ridiculous situation I will not name here a specific program...). Every (serious) image processing app. is tested, so chances are high to find a program, that supports TWAIN...

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Why doesn't this special application work ?

    TWAIN is a standard, but like every standard there is still room to interpret the protocol. Every feature of the data source (e.g. the frame grabber) can be inquired at run-time and according to the response be set. So the app and the source can agree on how to transfer the image and in which format. But of course there is always the chance that the app and the source don't "understand" each other, because the app want's something that the source can't do. E. g. PhotoShop want's the images in 64 kB slices, although under NT times have been gone where 64 kB is a magic limit. So the source has to be prepared to send these small slices. And some applications want the data in whatever format (YUV?), but don't ever tell what they want...

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What is the TWAIN protocol ?

    The TWAIN protocol is that much universal, that you can control with it everything. It supports single values, enumerations, ranges and arrays and for every of these templates all possible types like float, int, char... Everything can be decoded at runtime, so there is really a lot of place to make mistakes. At the bottom line, it's just some yes/no, possible/impossible or number parameters that are transferred, wrapped in a frame on information about what kind of data here comes.

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What is the difference to VfW?

    VfW (VideoForWindows) is the very first version from Microsoft to support capturing of video streams. Since then this interface has been several times recycled to be still available, although it isn’t the very best interface to support the current hardware. The big difference is, that a VfW driver is listed in the control panel -> multimedia -> devices -> video capture devices. The TWAIN driver is not. The TWAIN driver is a standardized protocol to talk directly to the hardware, whereas for the VfW interface the app talks to the OS, which forwards the request to the hardware.

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I installed the TWAIN driver, but still don´t see the grabber as capture device in my application, why?

    The reason for this is the fact, that the TWAIN protocol has nothing to do with the windows capture devices. Some applications like e.g. MS NetMeeting use capture devices listed in the Multimedia applet in the control panel, but there are the VfW devices listed, so this TWAIN driver will not solve this problem.

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What settings do I have to use during installation ?

    Depending on the frame grabber you have to select the “right” grabber during installation, so make sure you know what you have installed in your PC. Look in this zipped rtf file for some screenshots what selections to use during the MIL runtime installation.

    After the whole installation you have to select which TWAIN data source you want to use, this looks for Meteor2 like this

    Make sure that the selection here matches your hardware

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If you have any question or suggestion, don't hesitate to contact one of the following addresses:

general issues: Sales@EbboSoft.com

technical issues: Techsupport@EbboSoft.com

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