Mailing List Archive: MythTV: Users

HDTV digital static with DVB

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pc-mythtv05b at crowcastle

Nov 7, 2005, 11:48 AM

Post #1 of 17 (11766 views)
Permalink

HDTV digital static with DVB

I'm having trouble with digital static-like artifacts on my HDTV
recordings using the DVB drivers. This seems to be unrelated to signal
strength, but noticeably impacted by system load. If I'm watching a
recording or recording another channel on another tuner, the problem
gets worse.

I know that my system has the throughput to handle the bandwidth, so it
seems that there's some buffer that's too small, but I haven't been able
to find it.

This has been an issue with my HD-2000 card for several months, so it's
not a recent driver change.

My system:
HD-2000 with rooftop antenna for ATSC (works fine with video4linux drivers)
Air2PC HD-5000 with digital cable QAM (works perfectly with non-HD channels)
Kernel: 2.6.14 with CVS DVB drivers (for HD-5000 support).
All DVB drivers built into the kernel (not modules).

Probably irrelevant:
ivtv-0.4.0 for PVR-250
AMD 2500+
SATA drive
nVidia FX5200 with xvmc

cro at ncbt

Nov 7, 2005, 12:08 PM

Post #2 of 17 (11600 views)
Permalink

RE: HDTV digital static with DVB [In reply to]

Preston,

Sorry, I don't know the answer to your question, but I was wondering where
you are located physically and how you can tell that there are digital OTA
broadcasts in your area? I live in the Phoenix metro area (Chandler) and
can't seem to find any information on whether or not any of the local TV
stations are broadcasting digital (other than the local PBS affiliate KAET).

In addition, you mention a rooftop antenna for your digital ATSC setup--it
seems from reading I have done on the web that digital TV still broadcasts
in the VHF bands, so a "standard" VHF antenna should work fine?

Related to your original question, it sounds like you can't pinpoint when
this problem started. Has it always been the case that you get static with
the HD2000?

Not being a "real" Myth user as of yet, it "feels" to me that your cards are
not getting enough PCI bus bandwidth. You might try swapping the cards in
the slots (as sometimes preference is given to a card based on its slot), or
flashing the BIOS on your motherboard in case a recent BIOS update might
tinker with PCI timing. Those are just guesses on my part.

--cro

pc-mythtv05b at crowcastle

Nov 7, 2005, 12:28 PM

Post #3 of 17 (11605 views)
Permalink

RE: HDTV digital static with DVB [In reply to]

On Mon, 2005-11-07 at 13:08 -0700, C. R. Oldham wrote:
> I was wondering where
> you are located physically and how you can tell that there are digital OTA
> broadcasts in your area?

Near Boston, MA.

> I live in the Phoenix metro area (Chandler) and
> can't seem to find any information on whether or not any of the local TV
> stations are broadcasting digital (other than the local PBS affiliate KAET).

http://antennaweb.org/
Put in your address, and it will tell you what stations you can hope to
pick up, what type of antenna you will need, and what direction to point
it in. I was lucky in that all my stations are within five degrees of
each other, so a good directional antenna gets them all.

> In addition, you mention a rooftop antenna for your digital ATSC setup--it
> seems from reading I have done on the web that digital TV still broadcasts
> in the VHF bands, so a "standard" VHF antenna should work fine?

Nope, they're all UHF. For example, Fox KSAZ-DT is channel 10.1, but it
broadcasts on the frequency for UHF channel 31.

> Related to your original question, it sounds like you can't pinpoint when
> this problem started. Has it always been the case that you get static with
> the HD2000?

Always with the DVB drivers, but never with the video4linux drivers.
That's why I think it's a buffer size issue. With the DVB drivers, I
generally get perfect sound, and just a few squares or rectangles of odd
colors popping up every few seconds. Occasionally, it gets worse, and
may even skip over a fraction of a second on playback.

> Not being a "real" Myth user as of yet, it "feels" to me that your cards are
> not getting enough PCI bus bandwidth. You might try swapping the cards in
> the slots (as sometimes preference is given to a card based on its slot), or
> flashing the BIOS on your motherboard in case a recent BIOS update might
> tinker with PCI timing. Those are just guesses on my part.

Possible, but I don't know if that would explain the video4linux driver
working. That makes me suspect it's a driver issue, not a bus issue.

--PC

jc at dastrup

Nov 7, 2005, 12:29 PM

Post #4 of 17 (11591 views)
Permalink

RE: HDTV digital static with DVB [In reply to]

>Sorry, I don't know the answer to your question, but I was wondering where
>you are located physically and how you can tell that there are digital OTA
>broadcasts in your area? I live in the Phoenix metro area (Chandler) and
>can't seem to find any information on whether or not any of the local TV
>stations are broadcasting digital (other than the local PBS affiliate KAET).

http://www.antennaweb.org/ <http://www.antennaweb.org>

cro at ncbt

Nov 7, 2005, 12:53 PM

Post #5 of 17 (11587 views)
Permalink

RE: HDTV digital static with DVB [In reply to]

Greetings,

Thanks all for your replies--antennaweb.org is definitely what I needed.

--cro

ffrr at tpg

Nov 7, 2005, 11:14 PM

Post #6 of 17 (11602 views)
Permalink

Re: HDTV digital static with DVB [In reply to]

Preston Crow wrote:

>I'm having trouble with digital static-like artifacts on my HDTV
>recordings using the DVB drivers. This seems to be unrelated to signal
>strength, but noticeably impacted by system load. If I'm watching a
>recording or recording another channel on another tuner, the problem
>gets worse.
>
>I know that my system has the throughput to handle the bandwidth, so it
>seems that there's some buffer that's too small, but I haven't been able
>to find it.
>
>This has been an issue with my HD-2000 card for several months, so it's
>not a recent driver change.
>
>My system:
>HD-2000 with rooftop antenna for ATSC (works fine with video4linux drivers)
>Air2PC HD-5000 with digital cable QAM (works perfectly with non-HD channels)
>Kernel: 2.6.14 with CVS DVB drivers (for HD-5000 support).
>All DVB drivers built into the kernel (not modules).
>
>Probably irrelevant:
>ivtv-0.4.0 for PVR-250
>AMD 2500+
>SATA drive
>nVidia FX5200 with xvmc
>
>
>

I chased video glitches from my DVB setup for ages, and with a lot of
help from the list, I finally nailed it. It was the Si 3112 SATA
controller chip doing nasties on the PCI bus and corrupting the mpeg
stream from the DVB card.

This would correlate with your observation that it is worse with system
load, in particular disk access.

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pc-mythtv05b at crowcastle

Nov 8, 2005, 8:14 AM

Post #7 of 17 (11589 views)
Permalink

Re: HDTV digital static with DVB [In reply to]

On Tue, 2005-11-08 at 17:14 +1000, ffrr wrote:
> I chased video glitches from my DVB setup for ages, and with a lot of
> help from the list, I finally nailed it. It was the Si 3112 SATA
> controller chip doing nasties on the PCI bus and corrupting the mpeg
> stream from the DVB card.
>
> This would correlate with your observation that it is worse with
> system load, in particular disk access.

Not only that, but I bought a new SATA drive at about the same time as I
switched to the DVB drivers.

Did you ever get a good resolution?

I have an ASUS A7N8X Deluxe motherboard, which includes on-board a
Silicon Image Sil 3112A controller; the same one you found to be your
problem.

I suppose that if I can't fix some setting somewhere, then my best hope
is to buy a separate PCI SATA card with a different controller chip;
that would at least be cheaper than buying a new 400GB hard drive.

--PC

pc-mythtv05b at crowcastle

Nov 8, 2005, 5:35 PM

Post #8 of 17 (11584 views)
Permalink

Re: HDTV digital static with DVB [In reply to]

On Tue, 2005-11-08 at 17:14 +1000, ffrr wrote:
> I chased video glitches from my DVB setup for ages, and with a lot of
> help from the list, I finally nailed it. It was the Si 3112 SATA
> controller chip doing nasties on the PCI bus and corrupting the mpeg
> stream from the DVB card.
>
> This would correlate with your observation that it is worse with system
> load, in particular disk access.

I have two hard drives. If I simply cat /dev/dvb/adapter0/dvr0 to a
file on the SATA drive, I get some glitches. If I do the same to a file
on the PATA drive, I get tons of glitches. If I do it to a ram disk, I
get a perfect recording.

So it doesn't look like it's the SATA chipset doing something nasty. In
fact, the SATA drive, being on a faster bus, gives me a better recording
than the PATA drive. This makes it look more like my original theory of
being an issue that can be solved in the DVB driver. Of course, it
could be the SATA chipset or anything else on the PCI bus, but if
something were corrupting the DVB traffic, wouldn't it also corrupt
other traffic, like disk I/O?

Instead of it being a kernel buffer that is too small, perhaps it is too
slow to pull the data off of the card?

--PC

pc-mythtv05b at crowcastle

Nov 8, 2005, 8:04 PM

Post #9 of 17 (11577 views)
Permalink

Re: HDTV digital static with DVB [In reply to]

On Tue, 2005-11-08 at 20:35 -0500, Preston Crow wrote:
> I have two hard drives. If I simply cat /dev/dvb/adapter0/dvr0 to a
> file on the SATA drive, I get some glitches. If I do the same to a file
> on the PATA drive, I get tons of glitches. If I do it to a ram disk, I
> get a perfect recording.

And one more update: I've found the solution for the PATA drive is to
set the multisector I/O count to 16 (it was 0)
# hdparm -m16 /dev/hdc

Unfortunately, I don't seem to be able to set any useful parameters on
my SATA drive:
/dev/sda:
IO_support = 0 (default 16-bit)
readonly = 0 (off)
readahead = 16 (on)

Trying to change IO_support gives an error:
setting 32-bit IO_support flag to 1
HDIO_SET_32BIT failed: Invalid argument
It also doesn't seem to have a multisector I/O option.

So it does look like some performance improvements on the SATA drive are
what I need, but the tuning options aren't exposed.

--PC

wagspat at iit

Nov 8, 2005, 9:12 PM

Post #10 of 17 (11575 views)
Permalink

Re: HDTV digital static with DVB [In reply to]

> On Tue, 2005-11-08 at 17:14 +1000, ffrr wrote:
> > I chased video glitches from my DVB setup for ages, and with a lot of
> > help from the list, I finally nailed it. It was the Si 3112 SATA
> > controller chip doing nasties on the PCI bus and corrupting the mpeg
> > stream from the DVB card.
> >
> > This would correlate with your observation that it is worse with system
> > load, in particular disk access.
>
> I have two hard drives. If I simply cat /dev/dvb/adapter0/dvr0 to a
> file on the SATA drive, I get some glitches. If I do the same to a file
> on the PATA drive, I get tons of glitches. If I do it to a ram disk, I
> get a perfect recording.
>
> So it doesn't look like it's the SATA chipset doing something nasty. In
> fact, the SATA drive, being on a faster bus, gives me a better recording
> than the PATA drive. This makes it look more like my original theory of
> being an issue that can be solved in the DVB driver. Of course, it
> could be the SATA chipset or anything else on the PCI bus, but if
> something were corrupting the DVB traffic, wouldn't it also corrupt
> other traffic, like disk I/O?
>
> Instead of it being a kernel buffer that is too small, perhaps it is too
> slow to pull the data off of the card?
>
> --PC

I'm also experiencing the same behavior after a system upgrade from a
low end athlon to a nice new Athlon64. I just had a chance to do a
little debugging and I found that disabling the SiI chip and all of my
SATA ports did nothing. Furthermore, for me dumping it to a ram disk
did NOT produce a perfect recording or anything even close to it. It
was pretty sad indeed.

I also observed the signal levels on the card while I was getting the
stream and I noticed that signal levels dropped noticeable (from f8c4 -
near perfect) to cXXX and bXXX (where XXX varied), causing the signal to
lose out. This is very interesting and it suggests that the cards are
susceptible to some form of interference related to the bus. When I
leave the system idle it happily reports a perfect signal all the time.

Here's the hardware that I've got right now that may be relevant:
Athlon 64 3200+, MSI K8N-Neo4 Platinum, pcHDTV HD3000, wintv PVR250, a
bunch of IDE disk drives.

Before when the tuner was in an Athlon 700 with an Epox k7-kxa
motherboard the recordings were crisp and clean. Maybe it should just
back in there and I need to stream recordings over the network or
something.

I also started a thread on the pchdtv message board about this issue.
You can find it at: http://pchdtv.com/forum/viewtopic.php?p=6378

Unfortunately, I don't think that I'm skilled enough to do this sort of
debugging. Should we file this bug with pcHDTV or the DVB folks?

--Patrick

ffrr at tpg

Nov 9, 2005, 12:39 AM

Post #11 of 17 (11577 views)
Permalink

Re: HDTV digital static with DVB [In reply to]

Preston Crow wrote:

>On Tue, 2005-11-08 at 17:14 +1000, ffrr wrote:
>
>
>>I chased video glitches from my DVB setup for ages, and with a lot of
>>help from the list, I finally nailed it. It was the Si 3112 SATA
>>controller chip doing nasties on the PCI bus and corrupting the mpeg
>>stream from the DVB card.
>>
>>This would correlate with your observation that it is worse with
>>system load, in particular disk access.
>>
>>
>
>Not only that, but I bought a new SATA drive at about the same time as I
>switched to the DVB drivers.
>
>Did you ever get a good resolution?
>
>
Yep, swore long and loud at the manufacturers of such shoddy hardware
:-) , then built a whole new dedicated Knoppmyth system on an old 850MHz
box, using a 250GB IDE drive I went out and purchased.

Absolutely perfect recordings every time now !

>I have an ASUS A7N8X Deluxe motherboard, which includes on-board a
>Silicon Image Sil 3112A controller; the same one you found to be your
>problem.
>
>

Yep, many people have since told me horror stories about them.

>I suppose that if I can't fix some setting somewhere, then my best hope
>is to buy a separate PCI SATA card with a different controller chip;
>that would at least be cheaper than buying a new 400GB hard drive.
>
>

Well, what initially happened was, I was getting corrupt file systems
frequently. When I realised it was the controller, I found a BIOS
update that included/added a parameter to extend some obscure timing.
This had 4 setting from memory, something like 10us, 20us, 30us, and
1ms. That rang alarm bells as the doco said to try the first 3 and if
corruption still occurred, set it to 1ms. This is soooo much larger,
but guess what. I needed it set to 1ms to get reliable hard disks.

I am 99% sure that this new setting made my DVB glitches much worse. I
hadn't really noticed them before, as I think they were so infrequent, I
just put it down to signal noise. But now, they were intolerable. (This
was all using Mythtv under a Mandriva 2005le install)

I built a quick Knoppmyth install on an old 15GB IDE drive I had around,
and with the Sata drives disconnected, and obviously all other hardware
still the same, I had perfect pictures. This is the point that I built
the separate, non-SATA machine.

I still use the SATA machine as my daily desktop, and it is now
reliable. Just no good for DVB cards.
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ffrr at tpg

Nov 9, 2005, 12:43 AM

Post #12 of 17 (11565 views)
Permalink

Re: HDTV digital static with DVB [In reply to]

Preston Crow wrote:

>On Tue, 2005-11-08 at 17:14 +1000, ffrr wrote:
>
>
>>I chased video glitches from my DVB setup for ages, and with a lot of
>>help from the list, I finally nailed it. It was the Si 3112 SATA
>>controller chip doing nasties on the PCI bus and corrupting the mpeg
>>stream from the DVB card.
>>
>>This would correlate with your observation that it is worse with system
>>load, in particular disk access.
>>
>>
>
>I have two hard drives. If I simply cat /dev/dvb/adapter0/dvr0 to a
>file on the SATA drive, I get some glitches. If I do the same to a file
>on the PATA drive, I get tons of glitches. If I do it to a ram disk, I
>get a perfect recording.
>
>

But is your linux system running from the SATA drive? If so, it is
still being used - maybe by all sorts of background processes at the
same time. Booting from SATA drives, and putting the DVB data on an IDE
drive did not cure the glitches for me. Your ram disk experience is
interesting, but I think it may have worked because it was so very fast.

>So it doesn't look like it's the SATA chipset doing something nasty. In
>fact, the SATA drive, being on a faster bus, gives me a better recording
>than the PATA drive. This makes it look more like my original theory of
>being an issue that can be solved in the DVB driver. Of course, it
>could be the SATA chipset or anything else on the PCI bus, but if
>something were corrupting the DVB traffic, wouldn't it also corrupt
>other traffic, like disk I/O?
>
>

As per my other message (just sent) it did indeed cause disk problems
initially. That chipset is just rubbish! It sounds like your BIOS
already copes with the timing problem, as my BIOS update did, but with
the same unfortunate result for the DVB data stream.

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sean.walsh at agincourtgroup

Nov 9, 2005, 3:34 AM

Post #13 of 17 (11580 views)
Permalink

Re: HDTV digital static with DVB [In reply to]

> I chased video glitches from my DVB setup for ages, and with a lot of
> help from the list, I finally nailed it. It was the Si 3112 SATA
> controller chip doing nasties on the PCI bus and corrupting the mpeg
> stream from the DVB card.
>

I've recently had a similar issue migrating to FC4 and a new 300gb SATA
drive. I was getting the same "poor reception"
on DVB when the SATA drive was working hard. I was able to confirm that it

was the SATA drive alone through experimentation under my prior FC3
set-up.

My motherboard (gigabyte GA-K8NS Pro) has two pairs of SATA connectors -
one
pair near the edge of the card (and adjacent the outer most PCI slots -
where my DVB cards are) and another pair near the CPU socket. The pairs
use
different SATA controllers - one a Sil3512 and the other nVIDIA nForce3
250.

I observed a vast improvement just by swapping to the pair furthest from
the
DVB cards (nForce3). I still get occasional interference artefacts at
times
of high IO - but I'm hoping to play with shielding to resolve this. The 2
controllers are pretty much right next to each other but the Sil3512
controller that serves the outside pair is also a little closer to the DVB

cards slots. I don't know whether proximity to the DVB cards or the
chipset
is to blame for the interference.

Does anyone have any suggestions for effective shielding of either the
cards
for the SATA controller/cables?

ffrr at tpg

Nov 9, 2005, 3:57 AM

Post #14 of 17 (11570 views)
Permalink

Re: Re: HDTV digital static with DVB [In reply to]

sean.walsh [at] agincourtgroup wrote:

>
> > I chased video glitches from my DVB setup for ages, and with a lot of
> > help from the list, I finally nailed it. It was the Si 3112 SATA
> > controller chip doing nasties on the PCI bus and corrupting the mpeg
> > stream from the DVB card.
> >
>
> I've recently had a similar issue migrating to FC4 and a new 300gb SATA
> drive. I was getting the same "poor reception"
> on DVB when the SATA drive was working hard. I was able to confirm
> that it
> was the SATA drive alone through experimentation under my prior FC3
> set-up.
>
> My motherboard (gigabyte GA-K8NS Pro) has two pairs of SATA connectors
> - one
> pair near the edge of the card (and adjacent the outer most PCI slots -
> where my DVB cards are) and another pair near the CPU socket. The
> pairs use
> different SATA controllers - one a Sil3512 and the other nVIDIA
> nForce3 250.
>
> I observed a vast improvement just by swapping to the pair furthest
> from the
> DVB cards (nForce3). I still get occasional interference artefacts at
> times
> of high IO - but I'm hoping to play with shielding to resolve this. The 2
> controllers are pretty much right next to each other but the Sil3512
> controller that serves the outside pair is also a little closer to the
> DVB
> cards slots. I don't know whether proximity to the DVB cards or the
> chipset
> is to blame for the interference.
>
> Does anyone have any suggestions for effective shielding of either the
> cards
> for the SATA controller/cables?

That's not going to be easy to do.

But one question here first. If there's so much
electronic noise coming from the SATA controller/cables/disks, why don't
we hear it in
the audio? That's usually the first thing to suffer in an electrically
noisy environment.

You say that it is a lot better when you use the nForce controller.
Well given that the
early Si 3112 chip was so bad it even corrupted file systems, I can
believe your later
one is still inferior to the nForce chip. I guess I am saying it might
be a better engineered
chip that's producing the improvement, not proximity to the DVB card,
and that it might not be
electrical interference, but the way it uses the pci bus.

This is not unheard of. I remember early graphics cards, under Windows,
would cause
audio glitches when scrolling the screen (as in scolling a web page
under IE) because
the drivers were tweaked to give good benchmarks. In fact, they didn't
obey all the 'road
rules' on the pci bus, and jumped all over other card's useage of it.
It made them run faster though :-)
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ctrown at safe-mail

Nov 9, 2005, 9:01 AM

Post #15 of 17 (11584 views)
Permalink

Re: HDTV digital static with DVB [In reply to]

Preston Crow wrote:
> On Tue, 2005-11-08 at 17:14 +1000, ffrr wrote:
>
>>I chased video glitches from my DVB setup for ages, and with a lot of
>>help from the list, I finally nailed it. It was the Si 3112 SATA
>>controller chip doing nasties on the PCI bus and corrupting the mpeg
>>stream from the DVB card.
>>
>>This would correlate with your observation that it is worse with system
>>load, in particular disk access.
>
>
> I have two hard drives. If I simply cat /dev/dvb/adapter0/dvr0 to a
> file on the SATA drive, I get some glitches. If I do the same to a file
> on the PATA drive, I get tons of glitches. If I do it to a ram disk, I
> get a perfect recording.
>
> So it doesn't look like it's the SATA chipset doing something nasty. In
> fact, the SATA drive, being on a faster bus, gives me a better recording
> than the PATA drive. This makes it look more like my original theory of
> being an issue that can be solved in the DVB driver. Of course, it
> could be the SATA chipset or anything else on the PCI bus, but if
> something were corrupting the DVB traffic, wouldn't it also corrupt
> other traffic, like disk I/O?
>
> Instead of it being a kernel buffer that is too small, perhaps it is too
> slow to pull the data off of the card?
>

This thread has me wondering, now. I just got MythTV going and
have done some test records.

The Simpsons Halloween special recorded just fine, but it was in
SD format(Recorded from the HD channel). That same night, I tried to
record Law & Order:CI. That recording had a lot of breakups and qudio
dropouts.

The system is a 3.06GHz P4 with a HD3000 and a Rosewill Nvidia 5200FX.

My understanding is that recording DVB streams is not CPU
intensive. The card just grabs the digital data off the air and the
system writes it to disk for later manipulation/transcoding. Am I
correct? If that is true, then I am casting a suspicious eye to
problems with reception. I know that there is one channel that MythTV's
scan didn't pick up.

So I guess my question, is how can I tell if the problem I'm
seeing is trouble with recption vs. a possible system throughput issue?

Chris...

--
"Those who would give up essential liberty to purchase a little
temporary safety deserve neither liberty nor safety" -- Benjamin
Franklin
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ffrr at tpg

Nov 9, 2005, 7:25 PM

Post #16 of 17 (11541 views)
Permalink

Re: HDTV digital static with DVB [In reply to]

Chris Trown wrote:

>>
>>
>
>
> This thread has me wondering, now. I just got MythTV going and
> have done some test records.
>
> The Simpsons Halloween special recorded just fine, but it was in
> SD format(Recorded from the HD channel). That same night, I tried to
> record Law & Order:CI. That recording had a lot of breakups and qudio
> dropouts.
>
> The system is a 3.06GHz P4 with a HD3000 and a Rosewill Nvidia
> 5200FX.
>
> My understanding is that recording DVB streams is not CPU
> intensive. The card just grabs the digital data off the air and the
> system writes it to disk for later manipulation/transcoding. Am I
> correct?

That is my understanding of it as well, and what I see in practice.
Recording a show hardly loads the CPU at all.

> If that is true, then I am casting a suspicious eye to problems with
> reception. I know that there is one channel that MythTV's scan didn't
> pick up.
>
> So I guess my question, is how can I tell if the problem I'm
> seeing is trouble with recption vs. a possible system throughput issue?

It is hard. I would expect that true reception problems would be less
frequent and VERY random. I have yet to see a true reception problem on
mine - I am lucky that I have very good reception. Also, reception
problems would not correlate at system load and especially disk I/O.

Try starting a large file copy on the SATA drive while watching live TV
under Myth.

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wagspat at iit

Nov 27, 2005, 6:15 PM

Post #17 of 17 (11457 views)
Permalink

re: HDTV digital static with DVB [In reply to]

Like many people I'm experiencing issues with pcHDTV reception and
static under system load. Specifically, it manifests itself quite
severely when watching live HDTV or watching a recording while it is
recording.

In the previous thread[1] there was some speculation about the problem
being the SiI SATA controller, well, I'm fairly certain we can put those
rumors to rest - I've tried it on a system with an SiI controller and
without and the results were largely the same - as system I/O load
increases the noise in the recorded stream increases. I've posted quite
a bit of a rundown on my progress in this thread[2] at the pcHDTV
forums. Basically, I found that the problem also persisted when I was
heavily active on the network too. I tried saving the file to an NFS
drive and when I watched it while recording on the machine with the
pcHDTV (requiring a roundtrip of the data) I saw corruption. But I
could save the file to another computer and watch it on that computer
with no problem - no corruption what-so-ever.

So I've got a question for folks who have had good luck with the pcHDTV
and are able to watch live TV from it - what is the configuration you're
using? Do you have separate frontend and backend machine for the
configuration?

It seems like the solution for me would be to get another computer for a
backend and have it woken up when it should record. Obviously, this is
not an optimal solution.

--Patrick

[1] http://www.gossamer-threads.com/lists/mythtv/users/159591
[2] http://pchdtv.com/forum/viewtopic.php?t=1077

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