ATSC Guide - HDTV with less horsepower

[rwmech]

I'm hoping that sub makes this thread a sticky as I wanted to share my experience with developing an ATSC (HD) only system. I've seen others ask questions about ATSC/HDTV but I thought I'd take a moment to tie it all together. I'm hoping this gives anyone trying to do HD with GBPVR some heads up.

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!

[acegolfer]

My specs are as minimal as yours. I can watch pre-recorded HD while recording 2 HD shows simultaneously. See my specs below.

[marm]

Does the Purvideo make all that much of a differance? I have a AMD 3.2 and am using the Cyberlink decoder and am dissapointed in the quality, jumpy and skipped frames. I have a ATI 9700 Pro and recording and playback cpu usage are pretty low.

I also found out that the best so far is the MS-DVR works the best.

Thanks for the info it is nice to see in one place.

[lonegeek]

I got screwed when i bought my 6200, it supports hdtv output, but no mpeg 2 decoding! I might end up buying a new card eventually

[nitrogen_widget]

According to the Nvidia website the 6200 does support mpeg2 decoding via purevideo.

Is this not true?

[sub]

According to the Nvidia website the 6200 does support mpeg2 decoding via purevideo.

Is this not true?

Some 6200 models only do MPEG2 decoding accelleration on standard definition content, not the high definition which he needed: http://www.nvidia.com/page/purevideo_support.html

[rwmech]

Does the Purvideo make all that much of a differance? I have a AMD 3.2 and am using the Cyberlink decoder and am dissapointed in the quality, jumpy and skipped frames. I have a ATI 9700 Pro and recording and playback cpu usage are pretty low.

The real difference in the purevideo driver is that it enables the hardware accelleration. I'm not sure about ATI as they may do this as part of their standard driver. Nvidia however uses this as something else to sell you to a decoder driver that is "specific to your video card". Your processor seems to be a lot beefier as well.

Note that the Nvidia driver wont do anything for your ATI card, however ATI may sell something similar.

[86atc250r]

Does the Purvideo make all that much of a differance?

After getting mine set up properly - it made what I would consider a pretty significant difference in quality over any other decoder I had available.

Most noticible in sporting events and any program with a "scroller" at the bottom. Other decoders looked fine most everywhere execpt on something like an (American) football game - would get a lot more motion blur and it almost seemed as if the action was delayed or in slow motion even though frames weren't getting dropped with the other decoders.

With the purevideo decoder (and properly set up, which may take some doing), everything looks great - video quality is every bit as good as the feed going straight into the television and no more slow motion effect. Things "feel" sharper and more saturated with color as well.

In fact, with purevideo and an S-video cable running between the TV and computer, quality is substantially better than with the cable feed running to my VHS/DVD tuner and composite to the TV, which was my pre-GBPVR config.

FWIW, my box has plenty of HP - 3.06ghz Northwood on an ASUS board w/6600GT card on AGP. CPU utilization went down with Purevideo, but wasn't anywhere near maxing with the other decoders.

[nitrogen_widget]

Some 6200 models only do MPEG2 decoding accelleration on standard definition content, not the high definition which he needed: http://www.nvidia.com/page/purevideo_support.html

Thanks, I didn't notice this for some reason.

[lonegeek]

After reading some, i think mine may have mpeg 2 decoding. When i use the purevideo decoder the sdtv is like dropping every other frame, while hdtv is skipping alot.... Any ideas as to why?