[mythtv-users] Various questions

[Brian Steele]

On 9/22/05, kteague at speakeasy.net <kteague at speakeasy.net> wrote:
>
> <snip>
>
> After reviewing these products, I was under the impression that they're
> hardware *tuners* that do not perform any hardware encoding (which is left
> to the CPU/software). They have a new HD-5000 card that appears to boast
> more features than the previous card, with limited hardware support for
> demux'ing, but it doesn't appear as if it does full hardware encoding. This
> card is also able to receive unencrypted digital signals, so I believe my
> type of setup will fall under this category, and I should be able to use
> this card (if it's not simply just a tuner).
>
>
> http://mythic.tv/product_info.php?products_id=46&osCsid=7c5c1287a18541561a83e932b1d7c8fd
>
> <snip>



You are correct, they are hardware tuners and they don't perform any
hardware encoding. The reason they don't need to do this is that ATSC video
is already encoded and compressed into MPEG2 before it is broadcast. The
video recorded by the HD-3000 and Air2PC cards is just streamed over the bus
directly to the hard disk with very little CPU involvement. I have two
HD-3000 cards and can record with both at the same time while using less
than 5% of a 3Ghz Pentium4 CPU. Playback on the other hand, requires quite a
bit of CPU time. I average about 85-90% CPU usage when playing back 1080i
HDTV.
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