[mythtv-users] Hauppauge HD-PVR: Photos and link to pre-order
david at thegeorges.us
Tue Apr 8 02:08:52 UTC 2008
On 4/7/2008 8:44 PM, Brian Phillips wrote:
> David George wrote:
>> MPEG 4 encoding is extremely CPU intensive. To date there are no
>> chips that can encode two streams of raw HD data. With the size and
>> price point Hauppauge has aimed for it wouldn't be cost effective to
>> have a dual device. Even the highest performance TI DSP can't encode
>> two HD streams simultaneously (although it can encode a stream and
>> decode another at the same time). That isn't to say that someday
>> there will not be a dual device. Remember the PVR-500 came out
>> *several* years after the single tuner Hauppauge PVR cards.
>> Also when talking about power, these are not PC's. They have very
>> low power requirements compared to a PC.
> So put two DSPs on a single PCB.
I should have written more in my earlier email. The TI DSP I refer to
is actually a System on Chip (SoC). It is the only one that has an
HDVICP which is needed for compressing raw 1080i/p video. It is $135
for the chip, so it is a large part of the BOM. Other TI DSPs can do
720p and you could use more than one and add a separate processor, but
the people that would buy this would probably not be interested in a
1280x720 max resolution. Almost all of the other chips that support
1920x1080 are also SoC. There is a chip made by Fijitsu (MB86H51) that
supports 1920x1080 and should be able to support multiple chips with a
separate processor. I haven't been able to find a lot of details, but
the pricing info I've been able to find has this chip at about $200. At
these prices it is difficult to make a cost sensitive device.
> That's what the PVR 500 does
It has two special purpose MPEG2 compression chips. Would be nice if
Conexant made hi-res versions of it, but nothing so far.
> and probably
> (I haven't peeked inside) what the HDHR does.
HDHR has a single chip that just takes the already compressed stream
from over the air and packets it for the network. Doesn't require any
heavy lifting. I don't recall what the chip was off top of head, but it
was a small network processor.
> No one says they have to use
> a single DSP to do it. Anyone have an idea of what the cost of the DSP
> they're using is?
It doesn't use a DSP. It is a dedicated purpose IC from Ambarella.
> I don't imagine the DSP is the whole $250. Even if the
> chip was $50, that's still a $350 price point, or slightly more, to put two
> devices in the same footprint. If it needed to be slightly larger, so be
> it, but I doubt it would have to double in size and price just because it
> required another DSP.
> I could be wrong though as I don't actively price DSPs...
I don't know what the Ambarella chip costs, or if it is possible to put
multiple Ambarella chips and use an external processor like an ARM9 or
something for the USB (or ethernet interface). Ambarella's web site has
almost no information on it. TI and Analog are much more forthcoming
with datasheets and development information.
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