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Message from discussion Frame Callback to Array
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BeeJ  
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 More options Nov 7 2012, 2:41 pm
Newsgroups: microsoft.public.vb.general.discussion
From: BeeJ <nos...@spamnot.com>
Date: Wed, 07 Nov 2012 11:39:41 -0800
Local: Wed, Nov 7 2012 2:39 pm
Subject: Re: Frame Callback to Array
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>>    In the callback I receive the pic data as pData. [***]
>>          StretchDIBits Picbox.hdc, 0, 0, w, h, 0, 0, w, h, ByVal pData,
>> m_tBI, DIB_RGB_COLORS, vbSrcCopy
>>    ' this puts the full image in a picturebox.
> You haven't said exactly what you are getting in pData (see the line marked
> [***] above).

It is a callback from the WebCam.  I would have thought that the
      StretchDIBits
call would help identify the data format.

It places a WebCam frame into a picturebox that is viewed and looks
exactly as expected.  Axtually I take that BMP representation in PicBox
and convert it to JPEG.  That too works correctly.

 Is the data compressed, or is it straight bitmap data? If it is

> First check out the format of DIBSections:

> http://msdn.microsoft.com/en-us/library/windows/desktop/dd183567(v=vs...

> . . . and  and then check out SAFEARRAY structures:

> http://msdn.microsoft.com/en-gb/library/windows/desktop/ms221482(v=vs...

> . . . and then check out how you can use SAFEARRAY structures to "point"
> standard VB arrays at an existing block of data in memory, various examples
> of which you'll find in the archives for this group and others (but before
> you do either of those things check that you are not dealing with a
> compressed bitmap).

> Should be good homework for you ;-)

More like a thesis preparation.
Thanks.  I will see if this makes any sense to me.

 
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