[AG-TECH] Hi-quality video

Todd Needham toddn at microsoft.com
Mon Jul 23 11:06:47 CDT 2001


Bob do you have an MSDN subscription?  If not, let me know and I'll take
care of it as part of our general support of AG.

 

Todd Needham

Manager, Research Programs Group

Microsoft Research

http://research.microsoft.com 

 

-----Original Message-----
From: Jay Beavers [mailto:jbeavers at microsoft.com] 
Sent: Monday, July 23, 2001 7:40 AM
To: Robert Olson; Andy Quay; ag-tech at mcs.anl.gov
Subject: RE: [AG-TECH] Hi-quality video

 

Our stack has been written from the ground up according to RFC 1889 just
for this scenario.

 

Current FEC is primitive, just the redundant transmission of packets.
We're working on a parity packet scheme for the December release and
will follow RFC 2733 unless we hit a showstopper.  RFC 2733 looks
exactly like what we want to do so I foresee no problems.

 

I get bits to my application using the DirectShow SDK, where there are
plenty of examples of getting bits from a WDM source.  If you want to
talk to the WDM driver directly, I would search in the Device Driver Kit
for sample code.  I'll be happy to get you the DDK for Windows 2000 or
Windows XP.

 

We're not doing MPEG-4 encoding, Microsoft ships only an ISO MPEG-4
decoder in Windows XP.  We can source M-JPEG (and in the future MSVideo)
streams.  We're working on getting a contract in place to source h.261
and h.263 streams too.

 

-----Original Message-----
From: Robert Olson [mailto:olson at mcs.anl.gov] 
Sent: Monday, July 23, 2001 5:12 AM
To: Jay Beavers; Andy Quay; ag-tech at mcs.anl.gov
Subject: RE: [AG-TECH] Hi-quality video

 

At 03:52 PM 7/22/2001 -0700, Jay Beavers wrote:

We are doing 640x480 @ 15 fps using Sony 1394 cameras, encoding them
using software M-JPEG, and transmitting them with a RTP stack that
supports Forward Error Correction which we found to be a requirement
when sending large frame video.


Which stack is this? I've not paid much attention to FEC, but that
sounds cool. Is it an RFC2733 (http://www.ietf.org/rfc/rfc2733.txt) FEC
stack?



This system works side by side on the same box with analog capture cards
such as the Osprey 200 and Osprey 500 (which supports hardware
deinterlacing of NTSC signals).  We have found VIC quite unstable when
transmitting (receiving is just fine) video streams under Windows 2000
and Windows XP, so side by side on one computer is problematic at best
because VIC keeps crashing.  We've also found that VIC cannot deal with
our 1394 camera drivers which are based on the newer capture API WDM
(Windows Driver Model) instead of the older standard VfW (Video for
Windows).


Found this about WDM:

http://msdn.microsoft.com/library/en-us/dnwbgen/html/vidcap.asp

Do you have a simple example of video capture under WDM, where the
application code ends up with the bits from the camera?



We'll be releasing the RTP stack and a conference management application
in December per my previous message.  By December, I hope to have
support for not only M-JPEG (which is a bit of a CPU hog), but also ISO
MPEG-4 (decoding) 


What are you using for MPEG-4 encoding?

--bob

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