Hello,

I have been toying with getting an HD tuner card to add to my system. However, I am a bit concerned that my hardware might be just under powered. My FE/BE system is currently running a 2.8GHz P4, with 1GB RAM, ATI Radeon 7500 video using the DVI output (actually it's the ATI 7500 AIW), and the Hauppauge PVR-USB2 SD tuner. What I would like to be able to do (in order of my perceived system demands):

1) Playback an HD program
2) Playback an HD program while another program (HD or SD) is recording and running the commflag process
3) Playback an HD program while that same HD program is being recorded with commflag running

I get the feeling from searching that my current processor is enough to handle basic HD playback. I just don't know whether it would be enough to handle HD playback with the record and commflag running in the background. The few times I have checked with "ps aux" the mythcommflag process uses a little less than 25% CPU when running while the SD program is recording. I don't know if that would be more for processing an HD program.

Thanks for any input you can giv on this.

_________________
Tim

LinHES 8.4
HDHR3
BioStar A770, AMD X2 4050e, 2GB RAM
GigaByte GeForce 8400, Chaintech AV710
USB-UIRT

Recording HD takes almost no CPU, so you're ok there. Commflag can cause trouble, especially lately on the Athlon64. The default priority of 17 for "low cpu usage" isn't low enough, and I find myself renicing it to 19.

For a while, I could get away with commflag, record two HD programs and playback another one, but only on 720p, not 1080i. It was stuttering on 1080i unless I killed the commflag. So I mostly commflag overnight now, which means that I'm commflagging stuff that I've already watched. D'oh!

Anyway, I don't know where your processor stacks up against the Athlon64 3200, so I can't tell you for sure. But I suspect you'll be ok for playback, without commflag, while recording.

I just bought an Athlon X2 4200+ Dual Core and I can watch+commflag without problems, commflag takes up about 48% CPU and Watching takes up another 50. That leaves approx another whole CPU for other things.. It does a pretty decent job..

I used to run with a P4 2.8ghz system, 512MB RAM. I was able to playback HD, record an HD show and record an SD show all at the same time. Two important things to note:

1. I never deinterlaced 1080i recordings on playback -- my TV was able to directly accept 1080i and 720p. If I tried to deinterlace 1080i for playback at 720p, I would hit problems.

2. My P4 had hyperthreading and this was necessary. If I disabled hyperthreading, I ran into problems.

This was all under R5A30.2.

Marc

Just thought I'd update this thread with my results. As my sig indicates, I am running a 2.8GHz P4 with hyperthreading support with 1GB RAM. I just got an HDHomeRun and have finally gotten it configured properly. It took a while since Comcast strips out all of the data from their digital channels. Anyway, from my initial tests, I am able to at least record and playback an HD broadcast simultaneously. I have KM configured to run mythcommflag as soon as the recording starts. So I can run the commflag on an HD recording while watching that recording. So far, the few tests I have run were 720p broadcasts.

_________________
Tim

LinHES 8.4
HDHR3
BioStar A770, AMD X2 4050e, 2GB RAM
GigaByte GeForce 8400, Chaintech AV710
USB-UIRT

I'm "enjoying" this issue as well. Would you mind posting some steps to setting up the channel listings on R5E50? The channel scanner works for me and I can watch tv on several QAM channels with a lock. But I haven't been able to associate those channels with the appropriate Zap2It listings.

Did you have to edit the database by hand?

That's exactly what I did. And it was a tedious process that I wound up doing several times because I kept getting some parts wrong.

First I made a Zap2It listing with my OTA HD channels. Then ran mythfilldataabse to get that channel info into the database. Then I added the HD tuner card and associated it with the previously defined video source. After getting the tuner card defined, I ran a channel scan to detect the HD Channels. At this point, my program guide listed the both the TV channels from Zap2It and my scanned channels. At this point I edited the channel table in the mythconverge database. The relevant fields are: freqid, tvformat, mplexid, and serviceid.

I'm not really sure I can accurately describe how I corrected the data in this table. Especially since I did it wrong several times before it finally worked. Essentially, what I did was determine what each "UNKNOWN" channel (created during the scan process) really was. Then I copied the data from those channel fields to the rows that have the Zap2It data.

Once I got all done with that I deleted all of the "UNKNOWN" channel data. At this point I still wasn't able to tune those channels with the Zap2It listings data. I reran the channel scan, keeping the default of "Minimal Change" (typing this from memory) for the bottom option (don't remember what it was called). Once this scan completed, whatever was "confused" in the channel table got corrected and I was able to tune through the program guide.

However, after doing the final channel scan, my HD channels are scattered (seemingly randomly) throughout the program guide. I'm still trying to figure out how the channels are sorted. But at least they work. And scheduled programs record properly.

Hope this helps, but it was a rather trying process, and I don't think there is any way to make it any easier.

_________________
Tim

LinHES 8.4
HDHR3
BioStar A770, AMD X2 4050e, 2GB RAM
GigaByte GeForce 8400, Chaintech AV710
USB-UIRT

This is where I am now.


This part will be easy for me because I did this on my TV already when I first got it - before adding the myth box into the mix. I either recognized shows, or the channels had their station logo in the lower corner.


OK this is a really useful tidbit. I was afraid if I scanned again, that it would overwrite any hand-edits I made to the database. This will make things a lot easier.


Maybe you can go back into the database and delete the rows containing the unused channels that were added by the initial Zap2It OTA listing?


Definitely much appreciated.

I think the way to make it easier would be a script specifically designed to deal with Comcast. You could grab a channels.conf from

http://www.mythtv.org/wiki/index.php/Wo ... ble_layout

and then feed it into a script, and the script could do all the database updates for you, massaging things to work with the Zap2It listing. Maybe I'll get off my butt and work on such a thing this weekend if free time permits. Or someone could beat Comcast over the head with the stupid-stick and tell them to stop dropping the QAM channel-ids. But that only solves half the problem as Zap2It doesn't provide a "QAM listing".

How I did it was similar, I setup the listing and did the channel scan so I had all the unknows and all the listings showing. Then all I did was go to the channel editor in mythtv-setup and type in the XMLTVID for the correct channel in each of the Unknown entries, and also numbered and titled the station whatever I wanted. I left the second page of each channel config alone.
It is working perfectly so far. It is not as fancy as editing SQL I guess but if you don't have a huge number of channels to do I think it might be easier my way...

Edit: I believe Zap2it does do QAM listings, just look for the Digital Cable listings and remove any encrypted channels from the lineup.

_________________
MythTV box: Opty 170, MSI K8NGM2-FID, 1.5 GB PC2700, Seagate 7200.10 400GB, Lite-On Combo drive. PVR-150, HDHomeRun. Antec Sonata, Freezer 64 Pro. Oh so quiet.

Yeah, if I were to have to do this yet again, that may be the track I try. At first I thought it would be easier to modify the frequency and service IDs instead of editing the channel names and copying the XMLTVID. After seeing this through at least twice, I found I was editing the Zap2IT channel information along with all of the frequency info.

Probably would have been easier to go your route. That's the joy of this project and the forums: hopefully you can find someone else who has gone through the same trials, but found an easier method.

_________________
Tim

LinHES 8.4
HDHR3
BioStar A770, AMD X2 4050e, 2GB RAM
GigaByte GeForce 8400, Chaintech AV710
USB-UIRT

opel70,

You indicated that you have an HDHomerun tuner. I'm looking to purchase one of these in the very near future. I spent the weekend updating my Myth box to R5E50 in preparation for the arrival of an HDHomerun. I also have Comcast so I will have to edit my channel setup but I'm prepared for that.

My question is: Did you have to make any changes to get QAM tuning working on your HDHomerun in R5E50? I know that MythTV didn't support QAM on the HDHomerun until sometime in the fixes branch. I just want to double check that R5E50 uses a new enough version of Myth to allow proper QAM tuning with the HDHomerun.

Any insight you can provide would be much apperciated.

Thanks,

Martian

Yes, R5E50 works out of the box with the HDHomeRun. Other than dealing with figuring out all of the channels, there were no issues in getting it configured in KM.

Thanks opel70! That is great news. I spent the entire weekend (including the sleeping hours) doing a complete re-install (not upgrade) to R5E50 and I was so scared that I was going to have to update to an SVN version of myth in order to get QAM working on the HDHomerun. Thanks for putting my fears to rest!!!

I can't wait to start recording HD on my Myth box. Unfortunately I know I'm going to need to use xvmc for playback until I can afford some upgrades. At least with the latest version I can use xvmc only for HD.

Thanks again opel70!

Martian

_________________
ABIT NF-M2 nView | Athlon 64 X2 3800+ | 2GB DDR2 800 | HDHomerun | GeForce 6150 (onboard) | WD 640 GB SATA HD | DVD-RW (sata) | StreamZap IR receiver with Logitech Harmony remote

Vizio 37" LCD HDTV (1080p)

I am about to upgrade my R5D1 system to R5E50 with the intention of adding an HDHomeRun. One thought that keeps coming to mind is this: what is the expected longevity of hardware like the HDHomeRun in regards to encryption? As I look through my Comcast stations listings, I see many digital signals are encrypted.
I guess the question has two parts: the second part would be to ask if it would instead be more forward-looking to rent another HD cable box from Comcast...? I have the DCT-6200 right now, and it behaves itself pretty well...but it is the only HD tuner in my system, so it can be a chokepoint of sorts when I wish to record a digital or HD program. My PVR-250 will eventually go to the junk box since it is purely analog, so I'm trying to peer into the crystal ball to see how best to invest in my KnoppMyth system...

Thanks, opel70, for the tips on the HDHomeRun!!

-sTv

_________________
R7.3 Backend
CPU: 1.8 GHz
RAM: 2Gb
Drives: 500Gb IDE; IDE DVD-RW
Mobo: eMachines
Tuners (Analog): PVR-250
Tuners (Digital): DCT-6200 Motorola Cable Box, HDHomeRun (OTA + cable)

Well as far as longevity goes, the FCC requires cable companies to carry local broadcast channels unencrypted and unchanged. So those won't be going away. I assume that any channels you currently get through your 6200 are unencrypted, so the difference would only be the source as far as I can tell. If you are using an IR blaster and an analog output to get the encrypted channels off of the 6200 then points for the 6200. If you are interested in getting broadcast ATSC OTA signals at some point then points for the HDHomerun. Basically I think you will get the same selection of digital channels with either the 6200 or the HDHomerun.

_________________
MythTV box: Opty 170, MSI K8NGM2-FID, 1.5 GB PC2700, Seagate 7200.10 400GB, Lite-On Combo drive. PVR-150, HDHomeRun. Antec Sonata, Freezer 64 Pro. Oh so quiet.