I have a weird problem, that seems to be not too rare, in that my video playback is choppy. If you've ever watched a program using a dish network system during a storm, with the dish slightly loose, that's what it's like.

All kinds of crud appear on the program, I hear pops and snaps. (no crackles yet). Sometimes it will kill the front-end and/or the backend entirely and all recordings will stop. Using Alt-M to reload the front end will let me go to the menu and restart the box, or I can risk it and alt-3 and restart the backend too without rebooting.

I don't have to be actually watching for it to kill the backend. I've discovered the programs aborted a few minutes into the show or even mostly through the show.

Now, it works fine most of the time, and I can skip over the spots where it is especially bad. Last night, I'd recorded Medium and had to keep killing the recording and restarting it in the Upcoming Recordings menu in order to get it to record. Tried 4 times before I just tried watching it live.

What amazed me is THAT WORKED! Watching it live not only didn't have any problems, but it didn't have any buggy bits popping up.

I'm using R5E0, an 1800 mhz amd 64, 300mb HD, and an external network dual tuner (HDHomeRun) hooked up to the cable.

I do still have the Hauppage 500 analog dual tuner in the machine but it's not set to run off those tuners.

I've been searching through the forum but didn't see anything yet that quite answers what my problem could be. Any ideas?

Is the frontend/backend dying when you watch the recording or when it's trying to record? If it's dying while it's trying to record, what else is happening on the system at that time? Do you have any comm-flagging or transcoding jobs set to run during recording? Running top during that time may give some insight.

It dies both when just recording sometimes, even just a single show, and it dies sometimes when watching and recording. I'm not sure if it dies while just watching and not recording though.

I disable the commflag checkbox when I set up the recordings. I started doing this a while back thinking this was the problem. I don't know if it's doing any transcoding though. I didn't add anything specific to do transcoding.

Last night, it recorded 2 channels at once. One was mostly clean but the other was badly corrupted until the last 15 minutes or so. It didn't quit, but just was unviewable for most of it. Very choppy.

As far as I know, there are no other jobs running. I even made sure there's 15 hours of space available or more, since I thought maybe it was trying to do a few deletes to make space while recording.

If there are top would show you that...

What kind of signal strength do you see when watching live TV? And is the strength consistent? (Across channels, times of day, both tuners, etc.) On R5D1 my frontend would sometimes close down if my signal strength was too weak - Haven't had that happen on R5F27.

I don't have an HDHR so I don't have any specific troubleshooting help for it.

I'll try that.

I thought maybe the signal strength might be the problem, except that though it had trouble recording medium, watching it live worked fine. (On the same box, just clicking WatchTV.)

I didn't think there was any technical difference between recording and using watch tv though.

The one possibility that strikes me is that recording tried to use one of the two inputs, and watch tv just happened to select the other. I'll have to try to watch and see if I can determine if it happens just on one tuner. Maybe I have a bad cable to it.

(input cable to a splitter, to both hdhomerun inputs.) I'm not sure but I may have the splitter also going to my analog inputs for my hauppage as well as my vcrs. That would definitely weaken the signal.

well, seem to have figured out part of the problems.

I suspect mythfilldatabase would run in the evening. The info page shows it's been running around 4pm lately and I haven't really had the problem so much.

I had also deleted a bunch of shows previously to that, because I think when it was recording, it would end up low on space and try to do some deletes during recording. I've found that if I delete anything while a show is recording, it will mangle the new recording.

I think what happens is that it loses packets from the hdhomerun if the machine is otherwise busy on maintenance.

Also, I had my tv settings set to record 201 seconds beyond the end of a recording. Not sure if this causes a problem, say, for example, if 2 7pm shows are being recorded at once, 8pm hits and 2 new shows start recording, both on the same channels as the old shows. I have noticed that there's been recording overlap between them. The new recording and the previous recording on that channel would both have several minutes in common.

But I think at some point, it causes a glitch because about the 3 minute mark is when the backend would suddenly die. I believe it would always happen on the second recording too. Of course, I am not positive on that.

I'm also finding that the box would be at 96% ram memory being used even when not recording. I just watched a show, checked the page, and found it had 4% memory free. Restarted it and it shows most of the memory free.

So far, the last few weeks have been almost problem free, except for it dying on Tuesday when it started the 8pm recordings, but I've also been restarting it daily since then.

Yeah, other greedy activity during recording can cause a problem. Anything which requires heavy DB activity like mythfilldatabase is especially bad on that count.

I use a wrapper script to keep mythfilldatabase from running during my peak recording times for this reason. The idle.sh script published here is a good place to start.

In newer versions at least, there is a setup option to
"delete files slowly" which may help you if you are
being hurt by file deletions.

This is available somewhere in the frontend setup.

Cliff

_________________
R5F27 using R5F1 Nvidia drivers
HD-5500 analog from NTSC Sat Rx, with OTA DVB too
GeForce MX-440 SVideo tvout to a TV
Older dual core 3.4ghz Intel CPU
Asus P5PE-VM Motherboard
2 GB RAM
1 TB LVM2
VirtualBox
Samba

Actually I think you have to run mythtv-setup to do that. It's under "General". See - http://www.knoppmythwiki.org/index.php?page=GettingBackIntoMytTVsetup

Is this problem specific to the HD Homerun, or does it affect PCI HD tuners as well? So far I have had no problems with PCI HD tuners, but I was considering getting an HD Homerun.

It affects _all_ tuners SD or HD. If you don't read them fast enough they will overflow their buffers and lose data. It's a simple fact of life. Video recording and playback is a real time activity, and real time applications need to get their time slice and meet their deadlines or there are problems. Any other activity that increases the system latency to the point where that doesn't happen can trigger this. People have reported issues with mythfilldatabase, the rrd monitoring, ... and others too numerous to mention.