Friday, October 06, 2006

HARDWARE: Creating My own PVR for HDTV (ATSC) on a budget.

My installation from the get-go was a modest one. I didn't have a million bucks to throw into a PVR, just some spare parts and the purchase of the $39.99 Technisat Air2Pc card (eBay) and the Purvideo decoder $19.99. The rest I had already at the house.

Hardware Used:
Athlon XP 1600+ CPU
NVidia GeForce 5200 25MB Card (XFX Brand)
250GB Maxtor ATA-133 Drive
PC2700 Memory
Technisat Air2Pc (Generation 1) ATSC Card (BDA Driver)

Base Software Used:
NVidia Purevideo Decoder (formally DVD Decoder)
GBPVR v0.98.8
MS-DVR Mux

Though this I've learned a few things about ATSC and the setup above that I think will help everyone trying to get HD working (and working well) with their GBPVR setup.

Setting it up
1. Running v0.98.8
If your running v0.98.8 download the patches sub has put out at http://www.gbpvr.com/atsc-scan5.zip - This corrected my tuning (and many others) problem.

2. Decoding the HD signal requires a GOOD MPEG2 video decoder.

The Geforce 5200 (and above) models have hardware based decoding on the GPU. You can buy a 5200 card for $30 and because of the GPU the Purvideo decoder then offloads this from your CPU. When recording, and playing back under this scenario, I usually run around 60% CPU. 58% of that is the playback only 2% is recording.

I found that the Cyberlink decoder didn't do as good of a job. It used more CPU and couldn't take advantage of the GPU.

Don't be surprised if your video ends up choppy if you're running at near 100% CPU.

3. Mux settings.

Once again cyberlink mux didn't work as well as MS-DVR. Several threads here indicate that MS-DVR is the way to go, I agree. I get much better mileage from MS-DVR than .MPEG using cyberlink.

4. Antenna

I ran into some problems which I thought were hardware or GBPVR based with tuning. The fact of the matter is that this has a HUGE impact on your ability to get good HD signal. Some of this applies to general HDTV viewing not just recording. If you're serious about your setup there are 2 pages I suggest reading.

http://www.tvtower.com/hdtv_antenna_and_reception.html is written by a former Assistant Chief Engineer at a television station. This outlines that you shouldn't be using an amplifier as it can really hurt your signal. It also addresses issues in HDTV signal that many people may relate to GBPVR but are actually signal problems (as in my case). Skips, and choppy video can be interference not GBPVR, your Decoder or your CPU. This by far corrected many of my ATSC Tuner problems.

http://www.antennaweb.org/aw/welcome.aspx is a great site for tuning up your HDTV antenna. This allows you to actually adjust it for the direction and location you are at. Great information. This alone increased my reception by pointing in the most accurate direction.

If you have issues with "Choppy video", "Pixilization" and "Gaps in recording" it may be your antenna setup. Even though your "TV" may have good reception, I have found that tuner cards don't employ the same quality in signal filtering that a good TV will.

Recordings

1. Make sure you have drive space!

Recording in my area usually range around 6.7GB per hour (HD Quality). This can quickly eat up a hard drive. Be prepared to delete recordings when you are done.

2. SD takes up less space

Know which channels are transmitting in SD. If you record SD it's considerably less space than HD.

3. Defragment

If you don't defrag your drive and you record often, you can see issues with recordings.
http://www.compu-docs.com/W2KDfrag.htm is a great article on scheduling defragmentation at "off hours". Pick a good time when they are running infomercials!


Hope this helps someone I've got a lot of hours tied up getting this running. You can get HD for less money!

2 comments:

Reuben said...

I'm wondering, where did you get the BDA drivers for the Air2PC? It seems the unscrupulous company is SELLING the drivers separately on ebay ($15 plus tax) for those of us that bought the card previously. Did your card happen to come with them? I'd like to use this card with gbpvr, but without BDA it's impossible.
Thanks

Rob said...

I purchased my card with the drivers included. I think that's really crap they are selling a DRIVER. Sounds like somone needs some extra beer money.