Problems with OSX frontend - stutter/unusable

For discussion of topics specific to MythTV on OSX
lyricnz
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Re: Problems with OSX frontend - stutter/unusable

Post by lyricnz » Sat Jul 19, 2014 7:35 am

Plays OK via samba, a few stumbles here and there, averaging about 1MByte/sec. smbd CPU is kindof high - 10%, up to 30% for a few seconds. There's a few other things that run on this machine all the time (a couple of web-browsers, and damn pavucontrol/pulseaudio chewing up CPU), but machine is usually 80% idle. Box only has 2GB of ram, but looks like it's mostly buffers?

[root@mythtv ~]# free
total used free shared buffers cached
Mem: 2049660 1972872 76788 46332 1392 443436
-/+ buffers/cache: 1528044 521616
Swap: 4095996 1647556 2448440
[root@mythtv ~]#

I could upgrade to 4GB for about $50 if there's any point (but this is older hardware, memory is ddr2, so useless anywhere but here). FWIW, CPU is: Intel(R) Core(TM)2 Duo CPU E7300 @ 2.66GHz

lyricnz
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Re: Problems with OSX frontend - stutter/unusable

Post by lyricnz » Sat Jul 19, 2014 8:07 am

OK, uninstalled pulseaudio (death to pulseaudio!), booted machine into latest (fedora) kernel, turned off X and didn't run anything else. Machine hasn't touched swap. Same problem - plays for maybe a second, then stutter/freeze for 10 seconds, half a second playback, 10-20 more seconds freeze. AARGH!

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pvr4me
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Re: Problems with OSX frontend - stutter/unusable

Post by pvr4me » Sat Jul 19, 2014 2:23 pm

Maybe I haven't had enough coffee, but this is getting too difficult to follow. Are you saying that playback freezes on the the backend machine?

Or did you run Fedora on the Mac that was freezing?

Can we regroup for a minute? Please summarize the hardware and software of the backend and frontend. What tuner(s) are you using and what is the source format of the recordings? Do recordings play OK on the backend?

Craig
The MacPorts guy.

lyricnz
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Re: Problems with OSX frontend - stutter/unusable

Post by lyricnz » Sun Jul 20, 2014 9:12 pm

Backend+frontend (combined) is linux. Core(TM)2 Duo CPU E7300 @ 2.66GHz. 2GB RAM. Records and playback fine. Source is DVB card (quad digital tuner). Records without any issue at all. SD+HD recording to (I assume) mpeg2. I tried stopping the other things that are running on that machine, including pulseaudio and even X itself. Didn't help.

Other frontend is Macbook pro. 4GB ram. Gigabit wired network to backend (which seems to benchmark fine). Seems to empty buffer, then stutter trying to fill it. Can playback the mpg from filesystem mounted from backend via smb with very minor stutter (say a tiny glitch every 10-30 seconds, nothing like mythfe gets). I'm sure this *used* to be (6 months?) a perfectly adequate frontend. Something must have changed.

There's another machine on the LAN (imac) that I could test with, to check if problem is backend or frontend, but that's broken right at the moment.

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pvr4me
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Re: Problems with OSX frontend - stutter/unusable

Post by pvr4me » Mon Jul 21, 2014 1:56 pm

The backend is 0.27.1, right? Are you using the bundled OS X frontend from

http://www.avenard.org/files/mythtv/mac/

Which version? You haven't enabled any weird settings like the Crystal HD decoder or Advanced 2X de-interlacer?

Regardless, any MacBook Pro since 2007 will have enough grunt to play your recordings. Hardware problems do happen, though. Boot from another drive and use Disk Utility to check the system drive. If nothing reported, run Apple's Hardware Test:

http://support.apple.com/kb/ht1509

Unless you can demonstrate the same issue with your iMac, I don't think this is a Myth issue.

Craig
The MacPorts guy.

lyricnz
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Re: Problems with OSX frontend - stutter/unusable

Post by lyricnz » Tue Jul 22, 2014 9:56 am

Yup backend is 0.27.1 - and that's the frontend binary I'm running.

It used to work on this hardware, I can play a full HD recording mpg via SMB (almost) perfectly in VLC with deinterlacing and all that enabled (lower res works perfect); all settings in mythfe that I can see are pretty vanilla - and stutter happens even in a tiny window - so it's not output problem. A hardware/os problem on mbp seems most likely, I'll find a cable a connect the kid's imac, see if that works.

Can't run apple hardware test unfortunately, the optical drive in mbp has been broken for years.

lyricnz
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Re: Problems with OSX frontend - stutter/unusable

Post by lyricnz » Sat Aug 23, 2014 11:39 pm

OK, have confirmed on two other OSX machines, on the LAN via gige, that they all suffer the same stuttering/freezing problem. Very frustrating!

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Re: Problems with OSX frontend - stutter/unusable

Post by lyricnz » Sun Aug 24, 2014 12:26 am

Also, just checked: HTTP live streaming works perfectly, with all the transcoding and platform requirements there.

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stuarta
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Re: Problems with OSX frontend - stutter/unusable

Post by stuarta » Mon Oct 13, 2014 2:38 pm

Run some tests with iperf between the backend and the client to test the native throughput of the connection. See what bandwidth you can achieve here

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pvr4me
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Re: Problems with OSX frontend - stutter/unusable

Post by pvr4me » Mon Oct 13, 2014 2:55 pm

Wild stab in the dark...disconnect your LAN from the internet (power off the cable modem/whatever).

There was a report this morning on the SiliconDust forum where doing this fixed playback problems for another user. The catch...they're using EyeTV rather than Myth. They are still investigating/testing trying to determine _why_ this might help.

Craig
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