Hi Steve, Ben,
  I think the question was "Can producer encode Interlace content given a 
Interlace codec?"
  Other than just making sure that the input reaches the codec untouched I 
don't think there is much to the Producer architecture which will prevent 
interlace encoding. I think Producer should be able to hand down the input 
video frame to the codec without any filters in between,.. if the input 
type matches. The native color space of Interlace codecs is usually: YUV 
4:2:0, YUV 4:2:2, YUV 4:4:4.

  A> No filters introduced: Make sure all automatic filters are disabled. 
The interlaced codec should be able to accept YUV 4:2:0, 4:2:2 or 4:4:4. In 
case of the latter two there is no ambiguity and everything should just 
work. (Steve?) In case of YUV 4:2:0 there are two versions,.. top field 
first and the bottom field first. I don't know if there is a way to signal 
this or if it is implicitly assumed everywhere that it is always top field 
first (I420). (Steve?)

  B> Filters are introduced: This is complicated. If there is any color 
conversion, resize, or any other kind of filtering, it might happen in YUV 
4:2:0 color space and could impact the quality of the feed. Although many 
sensible decisions have been made during color conversion. E.g. RGB to yuv 
is done in one step. Other filters i don't know. Separate versions of 
filters for YUV 4:2:2 and YUV 4:4:4 may be required. (and a filter graph 
which will take the effort to connect them in the right order)

  RV9 assumes YUV 4:2:0 top field first. In this setting it doesn't really 
matter if any filters come into play. (except de-interlacing or inverse 
telecine of course). And a coded frame is always a pair of fields or a 
single progressive frame, so there should be no problem at the output. 
(mpeg2 & rv9 at least). Moreover I think the architecture is pretty 
flexible, it doesn't really matter.
  Steve is there a plan for a sample Video codec in the producer?

Thanks,
Neelesh

PS: BTW Rv9 interlace is not currently available in any producer release 
due to... zillion reasons.. i think mostly because no PC or graphics 
subsystem truly has interlace support,.. But the bitstream supports it. 
There is no Mpeg2 or DV or wmv9 codec in the producer either :)
http://www.realnetworks.com/solutions/leadership/realvideo.html

 >>>>
FYI -- Not sure if you are subscribed.
- Wolfgang

Mailing-List: contact dev-help at helix-producer.helixcommunity.org; run by ezmlm
To: dev at helix-producer.helixcommunity.org
Subject: [hxprod] [producersdk] [Fwd: Re: Producer DNA code release schedule?]
Date: Wed, 11 Dec 2002 16:53:48 -0800
From: Steve McMillen <stevemc at real.com>
Subject: [producersdk] [Fwd: Re: Producer DNA code release schedule?]

Anyone have any suggestions on the question below?
thx, Steve
-------- Original Message --------
Subject: Re: Producer DNA code release schedule?
Date: Tue, 10 Dec 2002 09:26:49 -0800
From: Ben Waggoner <ben at interframemedia.com>
To: Steve McMillen <stevemc at real.com>

Steve,
They're digesting it right now.
One question came up is whether it was possible to use Producer's code
to deliver interlaced frames to a codec that supports it, like MPEG-2,
QuickTime DV, or Windows Media 9.
Ben Waggoner <http://www.benwaggoner.com>
Compressed Video Consulting, Training, and Encoding
My Book: http://www.benwaggoner.com/books.htm
Compression Books: http://www.benwaggoner.com/bookshelf.htm

on 12/10/02 2:46, Steve McMillen at stevemc at real.com wrote:
Now that the code is out, please let your client know and let them know
I'd be happy to answer questions.
-
- Wolfgang Schildbach, Principal Codec Engineer, RealNetworks Codec Group
- fon +1-206-892 6349, em


Neelesh Gokhale ¤ ngokhale at real.com ¤ 206.892.6665
Codec Engineer
RealNetworks ¤ http://www.realnetworks.com
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