[FFmpeg-devel] DaVinci DSP optimizations

Luca Barbato lu_zero
Wed Apr 2 12:13:21 CEST 2008

Ramiro Polla wrote:
> The Texas Instrument DaVinci technology combines a general purpose
> processor (ARM) and, depending on the model, a few DSPs aimed at
> complete multimedia processing on a single chip.
> It is currently being used by some Set-Top Boxes and Personal Video
> Recording devices.
> Most devices depend on proprietary codec packages, and there is no
> open-source library that can use all the power of the DaVinci chips.

I see.

> This project aims at writing such optimizations to FFmpeg, and for
> that possibly write an infrastructure that can be used by other recent
> heterogeneous processor architectures, such as the PS3 CELL.

Sounds interesting.

> Neuros Technology uses DaVinci chips for their OSD2.0 devices.
> I'll elaborate on the idea:
> I don't have a PS3 nor have ever worked with one to know how it works
> with its DSPs, but I have worked some time with DaVinci.

the CELL's SPU aren't exactly DSP...

> I have contacted the folks at Neuros Technology for more information
> about helping out the possible mentor of such task with hardware or
> more information on the chip itself.
> One problem that they pointed out (and I think just might be the
> show-stopper) is that there are yet no free compilers for the DM6446
> DSP used by DaVinci.

That sucks.

> There was a port of GCC for the earlier DSPs, but I don't know how
> that's going with the new ones.

More informations would be useful.

> This is part of a reply I got from Joey Born and Ugo Riboni from
> Neuros Technology:
> ----------
> JB: There is no free compiler for the c64x DSP, although there are a number
> JB: of efforts to create one.  Your best bet is to try to get a loaner copy
> JB: of the developer tools from TI.  We have arranged some of these and can
> JB: probably help if you are selected.  You say DSP optimizations for which
> JB: codec?

> The problem is, the optimized code Ramiro will produce will be
> compilable only with these loaner versions of the compiler, and
> "normal" people can't use these, so they can't compile it.


> Thus getting that code in ffmpeg source feels pretty weird to me.
> Or is this not a concern ?

It is at least for me.

> One alternative may be lobby TI to release some stripped
> open-source-only version of that compiler, that can be freely used by
> OSS projects only.
> Just like they did with the c54x compiler.

Could be interesting in any case.

For the CELL we have quite a degree of support and knowledgeable 
mentors, but lack of students so far...



Luca Barbato
Gentoo Council Member
Gentoo/linux Gentoo/PPC

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