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From: "Eva" <mi...@uiuc.edu>
Subject: Do targa cards have the 2GB file size limit
Date: 1998/05/13
Message-ID: <6jdbka$50e$0@dosa.alt.net>#1/1
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subject say it all..

From: melo...@nospam.gov (Mel Matsuoka)
Subject: Re: Do targa cards have the 2GB file size limit
Date: 1998/05/14
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On Wed, 13 May 1998 18:50:39 -0500, "Eva" <mi...@uiuc.edu> wrote:

>subject say it all..
>


Targa boards do not have a 2GB filesize limit. No video card has a 2GB limit.
The 2GB barrier is entirely a limitation of the Microsoft
Video-for-Windows/ActiveMovie format, and nothing inherent in the videocapture
card itself.

aloha


____________________________________________________________________________
mel matsuoka                                Hawaiian Image Video Productions
Editor/Digital Media Dude			http://www.hawaiianimage.com
mel@EATTHISSPAMFORDhawaiianimage+com
 
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above address & replace plus sign with a dot to reply via e-mail)

From: ro...@ix.netcom.com (Roy)
Subject: Re: Do targa cards have the 2GB file size limit
Date: 1998/05/14
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On Thu, 14 May 1998 04:35:13 GMT, melo...@nospam.gov (Mel Matsuoka)
wrote:

>On Wed, 13 May 1998 18:50:39 -0500, "Eva" <mi...@uiuc.edu> wrote:
>
>>subject say it all..
>>
>
>
>Targa boards do not have a 2GB filesize limit. No video card has a 2GB limit.
>The 2GB barrier is entirely a limitation of the Microsoft
>Video-for-Windows/ActiveMovie format, and nothing inherent in the videocapture
>card itself.

True, no capture card is dependent on VFW for its actual existence in
the physical world, however the *operation* of many cards is entirely
dependent on VFW's AVI format. So, while it's true that no card has a
2GB limit if you're going to use it as a door stop, decorative dining
table centerpiece, or a paper weight,  most Windows capture cards that
will be used for video capture are subject to the 2GB limit by their
designed (i.e., inherent) use of/dependence on VFW.

My understanding is that, like the PVR, the Targas can operate using a
proprietary file format which does not have the same constraints as
the VFW .AVI.  Coupled with editing sw that can use this format (e.g.,
Speed Razor), the VFW limit is gone.

Roy

From: di...@netcom.com (William R. Dirks)
Subject: Re: Do targa cards have the 2GB file size limit
Date: 1998/05/15
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In article <355af178...@nntp.ix.netcom.com>,
Roy <ro...@ix.netcom.com> wrote:
>On Thu, 14 May 1998 04:35:13 GMT, melo...@nospam.gov (Mel Matsuoka)
>wrote:
>>On Wed, 13 May 1998 18:50:39 -0500, "Eva" <mi...@uiuc.edu> wrote:
>>>subject say it all..
>>Targa boards do not have a 2GB filesize limit. No video card has a 2GB limit.
>>The 2GB barrier is entirely a limitation of the Microsoft
>>Video-for-Windows/ActiveMovie format, and nothing inherent in the videocapture
>>card itself.

This is correct.

>True, no capture card is dependent on VFW for its actual existence in
>the physical world, however the *operation* of many cards is entirely
>dependent on VFW's AVI format. So, while it's true that no card has a
>2GB limit if you're going to use it as a door stop, decorative dining
>table centerpiece, or a paper weight,  most Windows capture cards that
>will be used for video capture are subject to the 2GB limit by their
>designed (i.e., inherent) use of/dependence on VFW.

I've written VfW capture drivers for video capture cards, and this isn't
exactly right. VfW consists of different pieces, and it's only the AVI
file format that has a limitation. 

No capture _card_ has a 2GB limit if you use it for VfW video capture 
either. A VfW video capture driver does not output an AVI file. A VfW 
driver only outputs a sequence of bitmaps. The application assembles the 
frames into some kind of video file.

The Microsoft DLL that comes with VfW has a convenience function (called
capCaptureSequence) that will automatically assemble frames coming from
the driver into an AVI file. Another Microsoft DLL has a rich set of
functions for manipulating the resulting AVI files. 

Most app developers use these functions rather than doing all the work of
creating a new format and rewriting all that functionality. But it is 
possible for an ambitious app developer to do that.

It's also possible for a board vendor to invent a file format and a
function library for accessing those files in an application, to add value
to his product. But you also have to find an app that can use that format. 

>My understanding is that, like the PVR, the Targas can operate using a
>proprietary file format which does not have the same constraints as
>the VFW .AVI.  Coupled with editing sw that can use this format (e.g.,
>Speed Razor), the VFW limit is gone.

Thanks for the info.

Bill.