[theora-dev] Next step of Hardware Theora

Sat May 12 17:49:50 PDT 2007

On 5/11/07, Leonardo de Paula Rosa Piga <lpiga at terra.com.br> wrote:
> On 5/11/07, André Costa <andre.lnc at gmail.com> wrote:
> > Thanks for Feedback,
> >
> > I have been talked with some people, we (I, Felipe and Leonardo) know a
> > group (that worked with us) that did a MPEG decoder in hardware at Brazil
> > and they have been helped us with some tips in others list. Also, I had a
> > chat with my professor and now I think it is more clear about LEON and SDRAM
> > controller.
> >
> > First, I agree with you, the priority should be the LEON. How Ralph said,
> > until this is done, no one else can play with the code.
> >
> > LEON3
> > figure 1:
> > http://www.students.ic.unicamp.br/~ra031198/leon3.JPG
> >
> > It is a excellent nonproprietay processor, very flexible and has a lot of
> > components that can be pluged (like Memory controller, jTag, AMBA).
> >
> > The steps would be:
> >
> > - To find a configuration that be able to decode the Theora.
> > - Synthesis of LEON3
> > - To compile only de initial part of Theora for LEON and to run this inside
> > of the LEON.
> > - To change the handshake of Theora Hardware of AVALON to AMBA protocol.
> > - Integrate the processor and theora hardware
> >
> > In think the hard part would be to debug this, construct a testbench to test
> > this. To learn the LEON3 features/configuration and the protocols would be
> > dificult too.
> >
> > SDRAM Controller and FlashCard
> > Yes. To do it in Hardware would be much complicate, because there are many
> > constrains and the SDRAM is very rigid with timing. For this, I would need
> > to have a good study of the datasheet before to start the developing.
> >
> > In the other list we had the ideia of work with a Flash Card, but It is very
> > slow. The Flash card would be nice to store the Videos encoded.
> >
> > LEON3/Memory Controller
> >
> > How you can see in figure 1, the LEON3 has a Memory Controller of SDRAM.
> > The LEON will use this to execute the functions of the intial decoding.
> > figure 2:
> > http://www.students.ic.unicamp.br/~ra031198/fig2.JPG
> >
> > Ok, then we can use this SDRAM memory controller to buffer of the Theora
> > Hardware?
> > Something like this:
> > figure 3:
> > http://www.students.ic.unicamp.br/~ra031198/fig3.JPG
>
> I don't like the implementation above. As you said I think that it
> might overload the AMBA bus.

Me too
I agree with Leonardo
The AMBA bus will be overloaded and will not be able to give the
throughput that we need.
This choice is not feasible.

>
>
> >
> > This answer I still don't, because it's depende of the AMBA, frequecie of
> > operation and data throuput. AMBA is a little slow, I think it will not get
> > to answer the LEON and Theora Hardware requests in time. But It is could be
> > tested.
> >
> > If it is not ok, the alternative would be copy the memory controller to use
> > with the SRAM
> > figure 4:
> > http://www.students.ic.unicamp.br/~ra031198/fig4.JPG
> >
>
> I think this is better because in this implementation the processor is
> used just for the software part. And if we have throughput problem we
> can easier convert to a pipelined implementation than the other one.

I agree with Leonardo.

>
> >
> > LEON3/VGA controller
> > Beyond this, LEON3 has a VGA controller, but I don't know if it would be
> > necessary to plug with Theora Hardware. But I think that could happen the
> > same problem of the SDRAM, It could overload the AMBA. And then, I think It
> > should be unpluged of AMBA and to plug directly with the Theora Hardware.
> > The group that we know did a Video Controller (for MPEG) in hardware. It
> > seems to be not much dificult to do, maybe it is more interesting to
> > Leonardo to do one.
> >
>
> Yes, I have studied the Lancelot VGA controller (this is the board we
> have in our laboratory). I'm thinking in developing the VGA controller
> as a separated module from Theora Hardware. In this manner the
> integration will be done by a simple handshake protocol.
> This would reduce the dependency between the VGA Controller  and the
> Theora Hardware.

This is good
A modular design is easier to develop and maintain too.

>
> >
> >
> > What do you think?
> >
> > André Costa
> >
> >
> > On 5/9/07, Timothy B. Terriberry <tterribe at vt.edu> wrote:
> > > >> Derf, what do you think?
> > >
> > > I don't know enough about the complexity implementing an SDRAM
> > > controller to say whether it should be one of the "primary goals" or a
> > > "secondary goal, time permitting". However, I think it would be nice to
> > > shoot for completing integration with Leon by the midterm date (the week
> > > of July 9; in approximately two months).  Then you will have the entire
> > > second half of the project to focus on the SDRAM controller. That may
> > > not be enough to finish it if it is really as complex as last year's
> > > entire GSoC project, but I would think you could make some good
> > > progress. When you talk to your professor tomorrow, he may be able to
> > > give you a better idea whether or not this is reasonable.
> > >
> >
> >
> >
> > --
> >
> > André Costa
> > Gerente Técnico
> > Projeto BrazilIP
> > LSC IC-UNICAMP
> >
> > Cel: + 55 13 9201 1870
> > http://www.brazilip.org.br/
>
>
> --
> Leonardo de Paula Rosa Piga
> Undergraduate Computer Engineering Student
> LSC - IC - UNICAMP
> http://www.students.ic.unicamp.br/~ra033956
>

-- 
________________________________________
Felipe Portavales Goldstein <portavales at gmail>
Undergraduate Student - IC-UNICAMP
Computer Systems Laboratory
http://www.students.ic.unicamp.br/~ra023772/