Just curious if anyone else has experienced this:

mythcommflag, even when running as a niced process, makes viewing recorded shows unwatchable. Every 1 to 2 seconds, the audio and video on the show I am watching pause for fraction of a second, creating this horrible non stop stuttering effect.

A quick "pkill mythcommflag" from the server prompt immediately removes all of the nasty stutters and the playback resumes silky smooth.

Viewing top with mythcommflag running shows mythcommflag using no more than 50% to 52% of the CPU, all of which are nice cycles, leaving a good 40+% of the cpu free, yet it stutters like all hell.

I run a 7200RPM ATA133 Maxtor drive with 16MB cache. DMA is turned on, so I don't think I am I/O bound, but I have not been to show this one way or another. hdparm shows me:
/dev/hda:
Timing buffered disk reads: 138 MB in 3.04 seconds = 45.42 MB/sec

45MB/s is fast in my book...

Any ideas on this? I basically had to just turn mythcommflag off, with a simple "mv /usr/bin/mythcommflag /usr/bin/mythcommflag.off" until I can resolve it, if it's even possible.

Maybe I just need a faster CPU, I don't know. Anyone else run the C3 Nehemiah and mythcommflag without problems?

Thanks for the help!

Another option is to schedule your commflag jobs to run while you sleep, that is what I do. I record FOX HD from 4pm until 8PM, and then have the commflag jobs run from midnight to 3am. Then I watch them the next day.

Also, if you have a slave box, or a different back end box from the frontend, you can have the other box run all of the commflag , and transcode jobs on it, leaving your front end just for watching.

This is what I am planning next, have another desktop in the house run all of the commflag/transcode jobs for me as a slave device.

Hope these ideas help.

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Knoppmyth R5D1 - Mythtv .20svn-fixes
HD Frontend/Master Backend
AMD64 3200+-1GB Corsair-800GB LVM PATA/SATA
Biostar GeForce 6100 Motherboard M109
1x Air2Pc rev.2 1x PVR150MCE
Maddog DVD/RW-DL Drive

The "nice" value for mythcommflag is 17. I get stuttering when running commflag unless I renice it to 19. I wish there was a setting for the nice value. Looking at the release notes, they changed from 19 to 17 a few revisions back, and I think it's hard-coded into Myth itself. I am thinking of writing a cron job that looks for it running at 17 and renices to 19. At 19, it's smooth enough to commflag primetime while I'm watching.

Forgive me for not being quite literate, but what is the command you run to "re-nice" commflag. This may help me in a situation when I am watching OTA-HDTV, and occasionally I get audio stuttering?

_________________
Knoppmyth R5D1 - Mythtv .20svn-fixes
HD Frontend/Master Backend
AMD64 3200+-1GB Corsair-800GB LVM PATA/SATA
Biostar GeForce 6100 Motherboard M109
1x Air2Pc rev.2 1x PVR150MCE
Maddog DVD/RW-DL Drive

I run "top", observe the PID, and then enter: r
then the PID value, then 19

Hey, thanks. I have been using Linux since kernel 2.14, and I did not know how to do that. Thank goodness for forums.

_________________
Knoppmyth R5D1 - Mythtv .20svn-fixes
HD Frontend/Master Backend
AMD64 3200+-1GB Corsair-800GB LVM PATA/SATA
Biostar GeForce 6100 Motherboard M109
1x Air2Pc rev.2 1x PVR150MCE
Maddog DVD/RW-DL Drive

Yeah, I have a beefy 3200+ AMD and still get exactly this hesitation untill I kill mythcommflag. It takes like 60% of the processor when it runs Keep me up to speed on the re-nice script.

_________________
Skill level: 10^-3

Subscribing to thread...

Interested in that re-nice script that I can cron.

Also - how do I schedule the mythcommflag to run during certain hours?
[edit]Turns out the answer to that is right here:
http://mysettopbox.tv/phpBB2/viewtopic.php?t=11842
[/edit]

Thanks!

-seano

re-nice script will get higher priority on my to-do list.
Wifey just woke me up to go and stop the @#$% commercial flagging, so she would watch Numb3rs.....

Yeah, that's a good way to do it. It's not ideal though. Ideally, and how I believe it's supposed to work is, mythcommflag would use only otherwise idle CPU cycles so you could flag as soon as possible.

_________________
Skill level: 10^-3

I'm getting this problem too. I just set my commercial flagging to only work from midnight to 6 am. But a script would be nice. I'd set it to a remote button, like the auto-restart frontend scripts.

About this topic. In mythtv-setup there is a field for Commercial Flagger command: this is filled in with "mythcommflag" why wouldn't it work to just replace that with "nice -n 19 mythcommflag"?

Try it and let us know!

there is also a renice command. no need to use top

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R5F1 - Dell P4 2.4Ghz 500MB - PVR250 x 2 - GeForce FX 5200 - Onboard sound/NIC 80GB ATA/250GB ATA/400GB SATA

Hi,

How much memory have you got ? Does your box swap ?
I havent got a solution to your problem but here is mine to compare:

I've got a via SP8000E which is also Nehemiah/C3 i guess, and 1GB memory.
Im not experiencing problems with stuttering playback during com-flagging. I tried with both nice 17 and 19 and there is no problem.
And this is even though it takes up a LOT of cpu (65-71%)


Perhaps the CN400 chipset is utilised during playback (it must be !?!). I dont know which chipset is on your M-board.

However I am experiencing trouble with mplayer stuttering when playing avi-files during com-flagging and this is tedious. (But thats probably better to address in another thread).

TV-Card: PVR-150
KM: R5E50 (fresh install, 2 days old)
Im using SATA which during com-flagging posts:
/dev/sda:
Timing cached reads: 142 MB in 2.03 seconds = 69.78 MB/sec
Timing buffered disk reads: 92 MB in 3.01 seconds = 30.56 MB/sec

And during recording:
/dev/sda:
Timing cached reads: 176 MB in 2.02 seconds = 87.15 MB/sec
Timing buffered disk reads: 104 MB in 3.04 seconds = 34.18 MB/sec

I think this should indicate that your problem is definitely not an io-bottleneck from HD but you're probably already aware of that.

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