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[Opendivx] Opendivx digest, c ša ki faut faire?




----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Friday, February 02, 2001 6:01 PM
Subject: Opendivx digest, Vol 1 #15 - 8 msgs


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> than "Re: Contents of Opendivx digest..."
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>
> Today's Topics:
>
>    1. Message replies in digest mode (Bez)
>    2. RE: Mpeg2 -> Mpeg4 (Nick Feamster)
>    3. Re: Mpeg2 -> Mpeg4 (Thomas Hargrove)
>    4. divx, the scope (ridaas syncprodz.com)
>    5. Re: NASM (Isaac Cruz Ballesteros)
>    6. x86 assembler portability (John Funnell)
>    7. decore/encore API change requests (Arpi)
>    8. unsubscribing (Calvin Redding)
>
> --__--__--
>
> Message: 1
> Date: Thu, 01 Feb 2001 20:07:26 -0800
> From: Bez <[email protected]>
> To: <[email protected]>
> Subject: [Opendivx] Message replies in digest mode
>
> Hi all. Just a quick reminder: when you quote someone's previous message
in
> your reply, please keep those quotes to a minimum. Do not quote their
entire
> message.
>
> The members of the list who are reading in digest mode have to scroll
> through the same message 10 times when 10 people respond and quote the
whole
> thing. :-)
>
> Cheers.
> :bez
>
>
>
> --__--__--
>
> Message: 2
> Date: Thu, 1 Feb 2001 23:30:08 -0500 (EST)
> From: Nick Feamster <[email protected]>
> To: Brian Smith <[email protected]>
> Cc: <[email protected]>
> Subject: RE: [Opendivx] Mpeg2 -> Mpeg4
>
> The main difference is that MPEG-4 is object-based, while
> MPEG-2 is frame based.  Both use similar block-matching tecniques and
> transforms.
>
> Nick
>
> On Thu, 1 Feb 2001, Brian Smith wrote:
>
> > 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
> >
>
>
>
> --__--__--
>
> Message: 3
> From: "Thomas Hargrove" <[email protected]>
> To: <[email protected]>
> Subject: Re: [Opendivx] Mpeg2 -> Mpeg4
> Date: Fri, 2 Feb 2001 00:22:52 -0800
>
> I think a mpeg2 -> mpeg4 is a great idea.  With the way the industry is
> looking right now, it could be an extremely popular tool.
>
> Possible uses:
>
> DVD -> DivX
>     yeah, duh
> Mpeg2 Caputre Cards (Hauppaug PVR) -> DivX
>     Usefull for creating a simpsons / south park archive
> Tivo -> DivX
>     It isn't possible yet, but it WILL happen.
> HDTV -> DivX
>     This might take a little longer.
>
> Just food for thought.
>
> --Tom
>
>
>
> --__--__--
>
> Message: 4
> Reply-To: [email protected]
> From: "ridaas syncprodz.com" <[email protected]>
> Date: Fri, 02 Feb 2001 01:00:46 -0800
> To: [email protected]
> Subject: [Opendivx] divx, the scope
>
> i checked projectmayo website but i have not really understood where open=
> divx project want to move.
> i see 2 possibility:
>
> 1)build something like an opensource core for mpeg4-compliants encoder/de=
> coder, of course some parts of mpeg4 will not be implemented as they are =
> of not real interest (example the synthetic stuff encoding etc..)
>
> 2)build something new from the scratch to do what mpeg2 was already doing=
>  but with better algos and ideas (can be aac or wavelets or whateva), mos=
> t important, just something free that allow you to encoded DVD movies whe=
> n ripped.
>
> i think 1) will be the ideal for everybody and can help a lot for the fut=
> ure opensource programs, actually i think it's not very clear if MPEG gro=
> up will be ALLOWED to publish a code implementation free for everybody of=
>  their standard, if the mpeg4 will be free or licensed and who will pay t=
> he license to who.
>
> 2) is of course easier to implement and can get rid off all the extra thi=
> ngs of mpeg4 we don't need when copying a movie.
> Does things like object-based encoding respect frame-based encoding reall=
> y help in divx or is just cause divx is directly borned from a mpeg4 enco=
> der?
>
> federico
> -------------------------------------
> http://www.syncprodz.com=20
> ------(mp3 since 1997)-------
> _________________________________________________________________________=
> __
> Visit http://www.visto.com/info, your free web-based communications cente=
> r.
> Visto.com. Life on the Dot.
>
>
>
> --__--__--
>
> Message: 5
> From: Isaac Cruz Ballesteros <[email protected]>
> Organization: SGI
> To: [email protected]
> Subject: Re: [Opendivx] NASM
> Date: Fri, 2 Feb 2001 10:05:23 +0100
>
> > 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 ;-)
>
> In allegro (a game programming library) we use .s files in AT&T format, so
to compile
> in windows you need some DJGPP tools (like GAS) to generate .o files,
which are linked
> with MSVC output.
>
>
> --__--__--
>
> Message: 6
> From: "John Funnell" <[email protected]>
> To: <[email protected]>
> Date: Fri, 2 Feb 2001 14:53:54 -0000
> Subject: [Opendivx] x86 assembler portability
>
> > Von: Gunter Ohrner <[email protected]>
> .....
> > Today I found a tool called intel2gas which automatically converts
> > Intel-style assembler code into the AT&T-syntax. It even does handle
MSVC
> > inline assembly sections in c-files. The translation looks usuable
> although
> > not directly compilable. intel2gas does not not seem to recognize
> > C-variable names within the inline assembler code and precedes them with
a
> > "%" and it can't convert "byte ptr [some_register]" constructs.
> > But maybe it's a start for automatic generation of the linux source
files.
>
> It sounds like this is almost working and that intel2gas would not need
much
> modification to work with our code.  I mailed the main author of intel2gas
> asking what would need to be done to make it work with our code.  It would
> even be worth changing our code slightly if that meant we only had to
> maintain one codebase for all x86 optimisations.
>
> For the C-variable names, intel2gas would have to replace the C names by
%0,
> %1, %2 ...etc. and then reference them as appropriate in the
> clobbered/input/output part.  I'm sure it shouldn't be too hard to handle
> the "byte ptr [some_register]" constructs.  If intel2gas could do this
then
> everyone would be very happy.  There's going to be a LOT of new MME, SSE
and
> other processor-specific stuff here eventually.  And, most likely it will
be
> available first as Intel-syntax inline C.
>
> On a different note, I just discovered that the demo Intel compiler can be
> run from Linux.  Install it on a Windows partition ('98 in my case).  Then
> use wine in Linux to run Intel's compiler: "wine icl.exe /c file.c".  This
> will make "file.obj".  You can convert this to "file.o" (elf format) by
> using objcopy [you may have to recompile binutils first, enabling pe-i386
> support].  "file.o" can then be linked into your Linux library or
> application.
>
> The above is a real bitch to set up, and compiles are slow, but you can
> automate with 'make'.  Both decore and encore build perfectly.  (This was
> using M$'s cl.exe by the same trick).  Perhaps in our makefile/configure
> setup for encore and decore we could have an option for people who have
the
> capability to do "wine (i)cl.exe".
>
> The Intel compiler is on a 30-day demo, so unless you can spare the cash
it
> may be of limited use but it is very good.  Comparable to pgcc ;-).
> Apparently, there's a native-Linux C++ compiler from Intel available soon.
> I doubt somehow that this will be free :-(
>
> John
>
>
>
>
>
> --__--__--
>
> Message: 7
> Date: Fri, 2 Feb 2001 16:21:00 -0600 (CST)
> From: Arpi <[email protected]>
> To: [email protected]
> Subject: [Opendivx] decore/encore API change requests
>
> Hi,
>
> I just want to ask you, opendivx core developers to do some
> little change on encore/decore interfaces.
> The only think I want is YUV (YV12 planar and maybe YUY2 packed)
> input and output.
>
> I've seen that encore wants Y,U,V pixels in 16-bit (short int) format
> instead of bytes. You should allow users to pass 16-bit/component
> images, so the application can do the conversion.
> (for example the decoder in the mpeg2->opendivx converter can be
> changed to output 16-bit/component pixels)
>
> In the encoder it's easy to add these changes: I'm using (in my
> linux encoder) the 'flip' flag to do this.
> CUrrently flip==0 means normal RGB image, and flip==1 means flipped RGB.
> I've added flip==2 for YV12 planar 8bit/component image, and the
> other formats (YV12 16bit and YUY2) can be added as flip==3 and ==4.
>
> For the decoder just see the libdecore for linux, it has this feature.
>
> YUV i/o is very important, because most of the current hardware &
> software (I mean windows/DX, linux/Xv, mac, beos) can do YUV overlays,
> and most file converters/recompressors use YUV internally
> (because most input formats (huffyuv, mjpeg, mpegs etc) are already
> YUV, so why convert it to rgb and then back to yuv?).
>
>
> A'rpi / Astral & ESP-team
>
> --
> mailto:[email protected]
> http://esp-team.scene.hu
>
>
> --__--__--
>
> Message: 8
> From: "Calvin Redding" <[email protected]>
> To: <[email protected]>
> Date: Fri, 2 Feb 2001 10:38:27 -0600
> Subject: [Opendivx] unsubscribing
>
> Hey guys, I've looked around, and can't figure out how to unsubscribe.
> Could someone please tell me how?
>
> Thanks!
>
>
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>
>
> --__--__--
>
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> End of Opendivx Digest

 
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