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Opendivx digest, Vol 1 #14 - 11 msgs



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Today's Topics:

   1. Multi-processor encoding/decoding ([email protected])
   2. NASM (Steve Pinkham)
   3. Development proposal (MBGA8CSH)
   4. gcc intel format (Steve Pinkham)
   5. RE: linux mmx decore... (Brian Smith)
   6. linux mmx decore... (Andrea Graziani)
   7. Re: linux mmx decore... (EtaBeta)
   8. Mpeg2 -> Mpeg4 (Ezra Auerbach)
   9. Re: Mpeg2 -> Mpeg4 (Nick Feamster)
  10. Changes & New Projects (Darrius "Junto" Thompson)
  11. RE: Mpeg2 -> Mpeg4 (Brian Smith)

--__--__--

Message: 1
To: [email protected]
From: [email protected]
Date: Wed, 17 Jan 2001 10:06:53 -0500
Subject: [Opendivx] Multi-processor encoding/decoding


I have little expertise in this area, but I know its possible to produce
encoders and decoders that can take advantage of SMP machines.  I'm bowing
out after this message, since I realize my own limitations, but please give
serious thought to providing this functionality, or at the very least not
prohibiting it through poor choices.

	Scott


--__--__--

Message: 2
Date: Sun, 21 Jan 2001 00:12:52 -0500
From: Steve Pinkham <[email protected]>
To: [email protected]
Subject: [Opendivx] NASM

Hello,
	Does anyone here have any experience linking assemb;y from NASM (which uses INTEL syntax) with gcc output?  Seems it would be easier then maintaining both formats, and the object files from NASM could be distributed in the tar files as they should be the same across any elf format intel machine.  That is, or course, if this is possible.. I'll look over it, but I'm still a rather marginal programmer ;-)

			Steve Pinkham


--__--__--

Message: 3
From: "MBGA8CSH" <[email protected]>
Organization:  University of Manchester
To: [email protected]
Date:          Mon, 22 Jan 2001 10:23:55 BST
Reply-To: [email protected]
Subject: [Opendivx] Development proposal

I did a bit of reading recently and realised why encoding divx is so 
slow.  The purpose of this post is for people to correct me when I'm 
wrong - please feel free to slaughter my idea!

Okay if you 'back up' an DVD you're encoding from YUV-RGB-DIVX.  The 
reason you can capture in realtime at good quality with MPEG-4 even 
on a low spec is because the process is only RGB-DIVX.  The solution 
to encode a dvd in realtime (or faster) is presumbably to rewrite 
divx to accept a YUV input, this way the following would be possible: 
YUV-DIVX.  

By eliminating this stage a lot of time would surely be saved.

Chris


--__--__--

Message: 4
Date: Wed, 31 Jan 2001 10:36:46 -0500
From: Steve Pinkham <[email protected]>
To: [email protected]
Subject: [Opendivx] gcc intel format

GCC can deal with intel format.. kinda ;-)
Just have to use NASM to compile the objects before linking... This only works for whole routines, not inline assembly though...

		Steve Pinkham



--__--__--

Message: 5
From: Brian Smith <[email protected]>
To: [email protected]
Subject: RE: [Opendivx] linux mmx decore...
Date: Thu, 1 Feb 2001 09:16:13 -0800 

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Use token pasting.

#ifdef WIN32
#define CSYM(a) a
#else
#define CSYM(a) _##a
#endif

...

_asm
{
	mov	eax, CSYM(c_var_name)
}

Wouldn't that work?  It's a bit more cumbersome, but I believe
it is better than enforcing the use of nasm.  I believe it would
be best to keep the SW requirements to a minimum so that it
encourages as many people as possible to work on the code base.
Most of us have very little time, and, frankly, I don't want to
waste it installing nasm.

Note: I don't use token pasting, so the above code could be totally
bogus.

Brian Smith
Senior Software Engineer
Cascade Microtech, Inc.

-----Original Message-----
From: John Funnell [mailto:[email protected]]
Sent: Thursday, February 01, 2001 08:57
To: Arpi; [email protected]
Subject: Re: [Opendivx] linux mmx decore...


This is a good idea.  Only (minor) problem is that you need a leading
underscore on every symbol for Windows and not for Gnu.

Could you Windows guys on the list cope with installing nasm and entering a
custom build step into your project? ;-)


Here's a summary of the three approaches for using assembler in our project
(let's ignore gas .s files):


(1) ** C with inline Intel-syntax **
In Windows Windows:  easy, use M$'s compiler
In Gnu/linux: you have 4 options
a. use wine to run cl.exe (or perhaps icl.exe though i haven't tried it yet)
b. run the code through intel2gas then use gcc/gas
c. wait for gcc to support inline intel syntax
d. hope that intel ports their compiler to linux
e. import a .o file compiled by someone who has one of the above!!


(2) ** C with inline gas (AT&T) syntax ** (I believe this is obsolescent)
In Windows:  use cygwin/gcc
In Gnu/linux:  use gcc


(3)** nasm format assembler files **
In Windows:  use nasm
In Gnu/linux:  use nasm


For now option (1), C with inline Intel-syntax, is the projectmayo prefered
option.  I'm sure everyone understands that is very important that we know
where the master, best, fastest MMX/SSE code is.  Ideally we should have
code that will build on any x86 platform.  nasm looks like that it might be
that utopia.....

Thoughts?

John



_______________________________________________
Opendivx mailing list
[email protected]
http://lists.projectmayo.com/mailman/listinfo/opendivx

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<P><FONT SIZE=2>Use token pasting.</FONT>
</P>

<P><FONT SIZE=2>#ifdef WIN32</FONT>
<BR><FONT SIZE=2>#define CSYM(a) a</FONT>
<BR><FONT SIZE=2>#else</FONT>
<BR><FONT SIZE=2>#define CSYM(a) _##a</FONT>
<BR><FONT SIZE=2>#endif</FONT>
</P>

<P><FONT SIZE=2>...</FONT>
</P>

<P><FONT SIZE=2>_asm</FONT>
<BR><FONT SIZE=2>{</FONT>
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT SIZE=2>mov&nbsp;&nbsp;&nbsp;&nbsp; eax, CSYM(c_var_name)</FONT>
<BR><FONT SIZE=2>}</FONT>
</P>

<P><FONT SIZE=2>Wouldn't that work?&nbsp; It's a bit more cumbersome, but I believe</FONT>
<BR><FONT SIZE=2>it is better than enforcing the use of nasm.&nbsp; I believe it would</FONT>
<BR><FONT SIZE=2>be best to keep the SW requirements to a minimum so that it</FONT>
<BR><FONT SIZE=2>encourages as many people as possible to work on the code base.</FONT>
<BR><FONT SIZE=2>Most of us have very little time, and, frankly, I don't want to</FONT>
<BR><FONT SIZE=2>waste it installing nasm.</FONT>
</P>

<P><FONT SIZE=2>Note: I don't use token pasting, so the above code could be totally</FONT>
<BR><FONT SIZE=2>bogus.</FONT>
</P>

<P><FONT SIZE=2>Brian Smith</FONT>
<BR><FONT SIZE=2>Senior Software Engineer</FONT>
<BR><FONT SIZE=2>Cascade Microtech, Inc.</FONT>
</P>

<P><FONT SIZE=2>-----Original Message-----</FONT>
<BR><FONT SIZE=2>From: John Funnell [<A HREF="mailto:[email protected]";>mailto:[email protected]</A>]</FONT>
<BR><FONT SIZE=2>Sent: Thursday, February 01, 2001 08:57</FONT>
<BR><FONT SIZE=2>To: Arpi; [email protected]</FONT>
<BR><FONT SIZE=2>Subject: Re: [Opendivx] linux mmx decore...</FONT>
</P>
<BR>

<P><FONT SIZE=2>This is a good idea.&nbsp; Only (minor) problem is that you need a leading</FONT>
<BR><FONT SIZE=2>underscore on every symbol for Windows and not for Gnu.</FONT>
</P>

<P><FONT SIZE=2>Could you Windows guys on the list cope with installing nasm and entering a</FONT>
<BR><FONT SIZE=2>custom build step into your project? ;-)</FONT>
</P>
<BR>

<P><FONT SIZE=2>Here's a summary of the three approaches for using assembler in our project</FONT>
<BR><FONT SIZE=2>(let's ignore gas .s files):</FONT>
</P>
<BR>

<P><FONT SIZE=2>(1) ** C with inline Intel-syntax **</FONT>
<BR><FONT SIZE=2>In Windows Windows:&nbsp; easy, use M$'s compiler</FONT>
<BR><FONT SIZE=2>In Gnu/linux: you have 4 options</FONT>
<BR><FONT SIZE=2>a. use wine to run cl.exe (or perhaps icl.exe though i haven't tried it yet)</FONT>
<BR><FONT SIZE=2>b. run the code through intel2gas then use gcc/gas</FONT>
<BR><FONT SIZE=2>c. wait for gcc to support inline intel syntax</FONT>
<BR><FONT SIZE=2>d. hope that intel ports their compiler to linux</FONT>
<BR><FONT SIZE=2>e. import a .o file compiled by someone who has one of the above!!</FONT>
</P>
<BR>

<P><FONT SIZE=2>(2) ** C with inline gas (AT&amp;T) syntax ** (I believe this is obsolescent)</FONT>
<BR><FONT SIZE=2>In Windows:&nbsp; use cygwin/gcc</FONT>
<BR><FONT SIZE=2>In Gnu/linux:&nbsp; use gcc</FONT>
</P>
<BR>

<P><FONT SIZE=2>(3)** nasm format assembler files **</FONT>
<BR><FONT SIZE=2>In Windows:&nbsp; use nasm</FONT>
<BR><FONT SIZE=2>In Gnu/linux:&nbsp; use nasm</FONT>
</P>
<BR>

<P><FONT SIZE=2>For now option (1), C with inline Intel-syntax, is the projectmayo prefered</FONT>
<BR><FONT SIZE=2>option.&nbsp; I'm sure everyone understands that is very important that we know</FONT>
<BR><FONT SIZE=2>where the master, best, fastest MMX/SSE code is.&nbsp; Ideally we should have</FONT>
<BR><FONT SIZE=2>code that will build on any x86 platform.&nbsp; nasm looks like that it might be</FONT>
<BR><FONT SIZE=2>that utopia.....</FONT>
</P>

<P><FONT SIZE=2>Thoughts?</FONT>
</P>

<P><FONT SIZE=2>John</FONT>
</P>
<BR>
<BR>

<P><FONT SIZE=2>_______________________________________________</FONT>
<BR><FONT SIZE=2>Opendivx mailing list</FONT>
<BR><FONT SIZE=2>[email protected]</FONT>
<BR><FONT SIZE=2><A HREF="http://lists.projectmayo.com/mailman/listinfo/opendivx"; TARGET="_blank">http://lists.projectmayo.com/mailman/listinfo/opendivx</A></FONT>
</P>

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--__--__--

Message: 6
Subject: [OpenDivx] linux mmx decore...
Date: Thu, 1 Feb 2001 10:45:10 -0800
From: "Andrea Graziani" <[email protected]>
To: <[email protected]>

First of all... thanks a lot to Carlo for his excellent ideas and
explanations.  :-)

We're also thinking to solve the portability problems of the MMX code
(windows, linux, ...) using intrinsic assembler instructions (macros).
This will also permit to automatically update (I hope) the ASM
instructions to the new processors...=20

Someone see problems from the linux side? The alternative will be to use
nasm.

Andrea



--__--__--

Message: 7
Reply-To: "EtaBeta" <[email protected]>
From: "EtaBeta" <[email protected]>
To: <[email protected]>
Subject: Re: [OpenDivx] linux mmx decore...
Date: Thu, 1 Feb 2001 10:58:41 -0800
Organization: ProjectMayo

First of all... thanks a lot to Carlo for his ideas and explanations.

We're also thinking to solve the portability problems of the MMX code
(windows, SSE/not SSE, linux, ...) using intrinsic assembler instructions
(macros). This will also permit to automatically update (I hope) the ASM
instructions for the future processors...

Someone see problems from the linux side? The alternative will be, for sure,
to use nasm.

Andrea






--__--__--

Message: 8
Date: Thu, 1 Feb 2001 21:53:05 +0200 (Jerusalem Standard Time)
From: "Ezra Auerbach" <[email protected]>
To: "[email protected]" <[email protected]>
Subject: [Opendivx] Mpeg2 -> Mpeg4


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Hi,
I'm a third year student in collage. Every student in my college must cho=
ose a project to do durring his third/fourth year. One of the projects on=
 the list was to write a program that converts mpeg2 to mpeg4 (or Mpeg1 t=
o Mpeg2 - but that isn't as interesting) without uncompressing the mpeg2 =
to a full bitmap and then recompressing...rather to use the compression t=
o further compress it to mpeg4.  (The professor in charge of the project =
said he himself doesn't know if it is possible.)

I wrote an email to the projectmayo team a while ago but haven't really g=
otten an answer yet, and I noticed a simular post here, so I was wonderin=
g if anyone can point me in the right direction. I kneed to know the foll=
owing:
1) Is this at all posible
2) Is it worth spending time on (will compressing mpeg2->4 this way achiv=
e the same quality, speed)
3) Do you think it can be done in about a year (2 people that don't know =
much about compression working 15-20hours a week)
4) Where can I find a information on mpeg compression. (I've started goin=
g through the offical mpeg site...but I couldn't find information about h=
ow the compression works in all the mpeg documentation there.)

Thanks for any help,
Ezra Auerbach
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      <DIV>
      <DIV>Hi,</DIV>
      <DIV>I'm a third year student in collage. Every student in my colle=
ge must=20
      choose a project to do durring his third/fourth year. One of the pr=
ojects=20
      on the list was to write a program that converts mpeg2 to mpeg4 (or=
 Mpeg1=20
      to Mpeg2 - but that isn't as interesting) without uncompressing the=
 mpeg2=20
      to a full bitmap and then recompressing...rather to use the compres=
sion to=20
      further compress it to mpeg4.&nbsp; (The professor in charge of the=
=20
      project said he himself doesn't know if it is possible.)</DIV>
      <DIV>&nbsp;</DIV>
      <DIV>I wrote an email to the projectmayo team a while ago but haven=
't=20
      really gotten an answer yet, and I noticed a simular post here, so =
I was=20
      wondering if anyone can point me in the&nbsp;right direction. I kne=
ed to=20
      know the following:</DIV>
      <DIV>1) Is this at all posible</DIV>
      <DIV>2) Is it worth spending time on (will compressing mpeg2-&gt;4 =
this=20
      way achive the same quality, speed)</DIV>
      <DIV>3) Do you think&nbsp;it can be done in&nbsp;about a year (2 pe=
ople=20
      that don't know much about compression&nbsp;working 15-20hours a=20
      week)</DIV>
      <DIV>4) Where can I find a information on mpeg compression. (I've s=
tarted=20
      going through the offical mpeg site...but I couldn't find informati=
on=20
      about how the&nbsp;compression works in all the&nbsp;mpeg documenta=
tion=20
      there.)</DIV>
      <DIV>&nbsp;</DIV>
      <DIV>Thanks for any help,</DIV>
      <DIV>Ezra Auerbach</DIV>
      <DIV>&nbsp;</DIV></DIV></TD>
</TR>
<TR>
<TD id=3DINCREDIFOOTER width=3D"100%">
</TD>
</TR>
</TBODY>
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--__--__--

Message: 9
Date: Thu, 1 Feb 2001 15:10:58 -0500 (EST)
From: Nick Feamster <[email protected]>
To: Ezra Auerbach <[email protected]>
Cc: "[email protected]" <[email protected]>
Subject: Re: [Opendivx] Mpeg2 -> Mpeg4

I wrote a real-time MPEG-2 to H.263 transcoder a while ago which bypassed
performing motion estimation upon re-encoding (although it did this in the
spatial domain).

http://nms.lcs.mit.edu/papers/paperspie.ps.gz

1. yes, it is possible.  but there are a few differences in the standard.
most notably, MPEG-4 is object-based.  But should pose no big problems I
don't think.
2. probably makes sense, simply because there's so much mpeg-2 content out
there (DVDs, etc.) which might be well served to be encoded to mpeg-4.
How much quality loss will be incurred is another question.
3. sure, probably a lot shorter.  optimizations would be worth looking
into as well.
4. http://mpeg.nist.gov/ and http://www.cselt.it/mpeg/

good luck!
Nick

On Thu, 1 Feb 2001, Ezra Auerbach wrote:

> Hi,
> I'm a third year student in collage. Every student in my college must choose a project to do durring his third/fourth year. One of the projects on the list was to write a program that converts mpeg2 to mpeg4 (or Mpeg1 to Mpeg2 - but that isn't as interesting) without uncompressing the mpeg2 to a full bitmap and then recompressing...rather to use the compression to further compress it to mpeg4.  (The professor in charge of the project said he himself doesn't know if it is possible.)
>
> I wrote an email to the projectmayo team a while ago but haven't really gotten an answer yet, and I noticed a simular post here, so I was wondering if anyone can point me in the right direction. I kneed to know the following:
> 1) Is this at all posible
> 2) Is it worth spending time on (will compressing mpeg2->4 this way achive the same quality, speed)
> 3) Do you think it can be done in about a year (2 people that don't know much about compression working 15-20hours a week)
> 4) Where can I find a information on mpeg compression. (I've started going through the offical mpeg site...but I couldn't find information about how the compression works in all the mpeg documentation there.)
>
> Thanks for any help,
> Ezra Auerbach



--__--__--

Message: 10
Date: Thu, 1 Feb 2001 19:29:35 -0800
From: "Darrius \"Junto\" Thompson" <[email protected]>
To: <[email protected]>
Subject: [Opendivx] Changes & New Projects


Well its only been 2 1/2 weeks and there has been some very productive
activity.  We've had tons
of great people helping.  There will be even more happening in the
coming week so please keep watching
and give us feedback. =20

There are also site changes, which will be happening freqeuently to make
the site much easier to work with
and actually see the activity.

And for the Finale, the following 3 projects have launched.  Remember
their projects and need work, so let us know if you
can help out.  And Thanks to our first Members of DORC for getting these
projects together and making it happen.


1.    DivX4Mac                    	Moderator:  AdrianB
2.    OpenDivX Streaming    		Moderator:  feamster
3.    FFMpeg                      	Moderator:  Hint


DivX4Mac	Moderator:	AdrianB
-------------------------------

I won't say much here except much thanks to AdrianB for making DivX4mac
happen!=20



FFMpeg	Moderator:	Hint
-------------------------------

FFmpeg is a real time video and audio encoder for Linux. It includes a
soft VCR and a=20
scalable live broadcast server compatible with most streaming formats.
The live broadcast=20
server can generate multiple bitstreams in real time at several
resolutions and bitrates at=20
the same time. All you need is a low end video grabbing card.

Most file formats and codecs are supported, including mpeg1, real, avi,
flash and (m)jpeg.=20
The latest version also includes support for OpenDivx real time
encoding.




OpenDivX Streaming	Moderator:	Faldo
--------------------------------------------

The OpenDivX streaming project is focused on developing streaming
technology and applications for=20
MPEG-4 bitstreams, specifically in the OpenDivX format. In particular,
we are addressing issues such
 as using RTP profile-specific extensions to provide selective
reliability, congestion control for=20
streaming video, and error resilience. The initial implementation of the
streaming application will=20
be in Linux and an extension to OpenDivX for Linux.




Junto
http://www.projectmayo.com


--__--__--

Message: 11
From: Brian Smith <[email protected]>
To: [email protected]
Subject: RE: [Opendivx] Mpeg2 -> Mpeg4
Date: Thu, 1 Feb 2001 12:03:48 -0800 

This message is in MIME format. Since your mail reader does not understand
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Correct me if I'm wrong, but the major advances in MPEG-4 over MPEG-2 come
from
different algorithms from the predicted B and P frames.  The DCT-based
compression
of the I-Frames is the same.  So, you'd have to decode the data to gain any
compression.

Brian

-----Original Message-----
From: Ezra Auerbach [mailto:[email protected]]
Sent: Thursday, February 01, 2001 11:53
To: [email protected]
Subject: [Opendivx] Mpeg2 -> Mpeg4


Hi,
I'm a third year student in collage. Every student in my college must choose
a project to do durring his third/fourth year. One of the projects on the
list was to write a program that converts mpeg2 to mpeg4 (or Mpeg1 to Mpeg2
- but that isn't as interesting) without uncompressing the mpeg2 to a full
bitmap and then recompressing...rather to use the compression to further
compress it to mpeg4.  (The professor in charge of the project said he
himself doesn't know if it is possible.)

I wrote an email to the projectmayo team a while ago but haven't really
gotten an answer yet, and I noticed a simular post here, so I was wondering
if anyone can point me in the right direction. I kneed to know the
following:
1) Is this at all posible
2) Is it worth spending time on (will compressing mpeg2->4 this way achive
the same quality, speed)
3) Do you think it can be done in about a year (2 people that don't know
much about compression working 15-20hours a week)
4) Where can I find a information on mpeg compression. (I've started going
through the offical mpeg site...but I couldn't find information about how
the compression works in all the mpeg documentation there.)

Thanks for any help,
Ezra Auerbach

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<BODY>

<P><FONT SIZE=3D2>Correct me if I'm wrong, but the major advances in =
MPEG-4 over MPEG-2 come from</FONT>
<BR><FONT SIZE=3D2>different algorithms from the predicted B and P =
frames.&nbsp; The DCT-based compression</FONT>
<BR><FONT SIZE=3D2>of the I-Frames is the same.&nbsp; So, you'd have to =
decode the data to gain any compression.</FONT>
</P>

<P><FONT SIZE=3D2>Brian</FONT>
</P>

<P><FONT SIZE=3D2>-----Original Message-----</FONT>
<BR><FONT SIZE=3D2>From: Ezra Auerbach [<A =
HREF=3D"mailto:[email protected]";>mailto:[email protected]</A>]</F=
ONT>
<BR><FONT SIZE=3D2>Sent: Thursday, February 01, 2001 11:53</FONT>
<BR><FONT SIZE=3D2>To: [email protected]</FONT>
<BR><FONT SIZE=3D2>Subject: [Opendivx] Mpeg2 -&gt; Mpeg4</FONT>
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<P><FONT SIZE=3D2>Hi,</FONT>
<BR><FONT SIZE=3D2>I'm a third year student in collage. Every student =
in my college must choose a project to do durring his third/fourth =
year. One of the projects on the list was to write a program that =
converts mpeg2 to mpeg4 (or Mpeg1 to Mpeg2 - but that isn't as =
interesting) without uncompressing the mpeg2 to a full bitmap and then =
recompressing...rather to use the compression to further compress it to =
mpeg4.&nbsp; (The professor in charge of the project said he himself =
doesn't know if it is possible.)</FONT></P>

<P><FONT SIZE=3D2>I wrote an email to the projectmayo team a while ago =
but haven't really gotten an answer yet, and I noticed a simular post =
here, so I was wondering if anyone can point me in the right direction. =
I kneed to know the following:</FONT></P>

<P><FONT SIZE=3D2>1) Is this at all posible</FONT>
<BR><FONT SIZE=3D2>2) Is it worth spending time on (will compressing =
mpeg2-&gt;4 this way achive the same quality, speed)</FONT>
<BR><FONT SIZE=3D2>3) Do you think it can be done in about a year (2 =
people that don't know much about compression working 15-20hours a =
week)</FONT></P>

<P><FONT SIZE=3D2>4) Where can I find a information on mpeg =
compression. (I've started going through the offical mpeg site...but I =
couldn't find information about how the compression works in all the =
mpeg documentation there.)</FONT></P>

<P><FONT SIZE=3D2>Thanks for any help,</FONT>
<BR><FONT SIZE=3D2>Ezra Auerbach</FONT>
</P>

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