On Jun 30, 2009, at 1:59 AM, Silvia Pfeiffer wrote:
- has off-the-shelf decoder hardware chips available
"decoder hardware" for video means that there are software libraries
available that use specific hardware in given chips to optimise
decoding. It is not a matter of hardware vendors to invent new
hardware to support Theora, but it is a matter of somebody
implementing some code to take advantage of available hardware on
specific platforms. This is already starting to happen, and will
increasingly happen if Theora became the baseline codec.
I looked into this question with the help of some experts on video
decoding and embedded hardware. H.264 decoders are available in the
form of ASICs, and many high volume devices use ASICs rather than
general-purpose programmable DSPs. In particular this is very common
for mobile phones and similar devices - it's not common to use the
baseband processor for video decoding, for instance, as is implied by
some material I have seen on this topic, or to use other fully general
DSPs.
Some H.264 ASICs are internally implemented as completely hardcoded
logic. Others are implemented as a relatively general purpose DSP with
a custom instruction set and microcode set by the manufacturer. Even
these theoretically more general chips cannot be programmed by the
device vendor, only the manufacturer of the chip itself. ASICs often
have a significant cost and power consumption advantage compared to
other solutions, at least in medium to high volume applications.
A Google search for "H.264 decoder ASIC" shows that these are
available from many manufacturers: <http://www.google.com/search?q=H.264+ASIC
>.
As far as I know, there are currently no commercially available ASICs
for Ogg Theora video decoding. (Searching Google for Theora ASIC finds
some claims that technical aspects of the Theora codec would make it
hard to implement in ASIC form and/or difficult to run on popular
DSPs, but I do not have the technical expertise to evaluate the merit
of these claims.)
Regards,
Maciej
