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RE: Looking for a way to record HD OTA broadcasts.

Posted by Jim Doyle on May 5, 2008 at 20:16:03:
It's doable, but complex, and it can be expensive. It's called
MythTV. You need to comfortable with Linux, you need to know how to
select hardware too.

Here's the skinny:

The bitstream comes in over the air at 22 Mbits/sec. So, to record
this, it has to go to hard disk and it stores out at 2.75 MB/second, or,
9.9 GB/hour. One hour of recorded data exceed the capacity of a burnable
DVD! This makes it difficult to record an hour long program to DVD, so,
if you're going to record OTA, you'll need a disk storage facility 500GB+
to retain a archive of recorded programming - more if you want a historical archive... You can downconvert the OTA bitstream and lose resolution to make it more recordable to DVD, but the computational complexity of the downconversion can take hours on high powered CPUs.
High throughput CPUs dissipate alot of heat and use alot of electrical poweer. So, now you're talking a dedicated PC with a dual or quad core CPU, external eSATA disk array etc. If you dont need to downconvert
resolution, you can use a lower powered CPU and a big disk array.

I used Mythbuntu to do this (www.mythbuntu.org). You'll need to buy
an HDTV tuner card. I recommend highly the Silicon Dust Dual Tuner ($170), or the Pinnacle PCI HDTV tuner. If you do the Silicon Dust, use a
DEDICATED 100Mbps ethernet network for the video stream. You can
use a cheaper motherboard (An AMD Sempron 3000+ is fine). Plan on Firewire 800 or eSATA as your storage bus because you WILL be stacking up hard drives to expand storage often. Last but not least, you'll be spending at least $80 on a video board that has MPEG2/MPEG4 hardware assisted decode.

I couldnt imagine the cost of a turnkey consumer product to solve this problem... Even with MythTV and Linux, its $500 in computer parts to get a solution built!

As far as MythTV, I use it to record OTA HDTV. I work nutso hours, so when I am home, I am able to watch my favorite OTA shows in Hi Def on my own time!

-- Jim