Live TV stutters every 6 minutes

[peterbonge]

If you still have the NPVR cache settings set to 6 min, and it is doing this once every 6 min?? The file opening/file closing may require more power to the HDD. If you have a powered USB hub sitting around, go ahead and give it a try using it as a power injector. If you don't then you will never know. No changes need to be made to the system. Just plug it in and try it.

The problem starts after 12 minutes and then occurs every 6 minutes. So after the first file the problem doesn't occur. Surely because the first file gets written continuously.

So far I didn't found an USB hub here, but I doubt that it will help. USB 2.0 can't offer the speed to write the files fast enough. If writing the file and switching to the next one takes up to 4 seconds it is just too much for a smoothly playback.

I've just tried to reduce that cache file (SlipSeconds). The cache files were really small and the playback worked without any problems, but pausing and then resuming didn't work good anymore. I got breaks, stutters and sometimes there was no audio.

Tomorrow I will search again for an USB hub and test it.

[anothernewbie]

I don't know what the channel bandwidth is for you but in USA, OTA is MPEG2 and 2.35 MBytes/s max and usually < 2.0. You're probably getting H.264 and if your bandwidth is that high, I'm jealous.

The point is that USB 2.0 is usually good for 25 MBytes/s and you probably need 5 MBytes/s max to write and read the data for live TV on a single channel. That said, I wouldn't want to use a 2.5" USB drive because of reliability concerns in DVR use.

How full is the drive? I'd suggest checking to see how fragmented it is. File Explorer, Right click on drive, select Properties, Select Tools, select optimize/defragment, select analyze.

Sounds like the glitches happen when Windows has to open a new file on the drive and if the drive is highly fragmented and/or space is limited, that may be causing a delay.

I suspect if you increase the SlipSeconds to a large value (1 hour or more) as suggested, you'll probably at least largely mask the issue.

[peterbonge]

... you probably need 5 MBytes/s max to write and read the data for live TV on a single channel.

The files have a size of about 180 MB. The first files gets written with about 0.5 MB/s and all other files are written with about 0.03 MB/s at the beginning. Now guess what speed is needed at the end of the file.

How full is the drive? I'd suggest checking to see how fragmented it is. File Explorer, Right click on drive, select Properties, Select Tools, select optimize/defragment, select analyze.

The last drive I've tested was an USB memory drive. 30 GB and nearly empty. So no defragging necessary.

I suspect if you increase the SlipSeconds to a large value (1 hour or more) as suggested, you'll probably at least largely mask the issue.

And I suspect that the stuttering will occur less often, but much heavier. I will test this tomorrow.

[BrettB]

The files have a size of about 180 MB. The first files gets written with about 0.5 MB/s and all other files are written with about 0.03 MB/s at the beginning. Now guess what speed is needed at the end of the file.

Other than it not affecting the first file written, this behavior (the "delayed writing") sounds very similar to one we were seeing with recordings via the HDHR Primes. See:

Yeah, it must be something Windows is doing. As far as NextPVR can tell, it's writing to disk regularly.

Can you see if this patch makes any difference?

Sub never told us what he found/changed, but it definitely made a difference for us with the HDHR Prime recordings.

Have you tried reinstalling NextPVR with the current installer to make sure that you have all the current patches? (Note that the version numbers will still be the same, so you need to actually download the latest installer and run it even if it says it's the same version.)

[peterbonge]

Have you tried reinstalling NextPVR with the current installer to make sure that you have all the current patches? (Note that the version numbers will still be the same, so you need to actually download the latest installer and run it even if it says it's the same version.)

I've installed the NPVRSetup_3_4_8.exe which I've downloaded on 20. July. Shouldn't that be the latest one?

And I've just tested to increase the SlipSeconds value to 5000. Now the problem occurs about every 28 minutes, but (as expected) the playback then stops for about 3-4 seconds. The playback stops as long as the system needs to write the ~500 MB file.

[BrettB]

I've installed the NPVRSetup_3_4_8.exe which I've downloaded on 20. July. Shouldn't that be the latest one?

And I've just tested to increase the SlipSeconds value to 5000. Now the problem occurs about every 28 minutes, but (as expected) the playback then stops for about 3-4 seconds. The playback stops as long as the system needs to write the ~500 MB file.

Yes, I'm sure that would be the latest installer.

It really does sound similar to the problem we had with HDHRs. Maybe when sub is back home (should be soon), he can find the problem and get you a patch.

[ACTCMS]

Have you tried playng with window's Write Caching policies for the USB disk? It sounds counter-intuitive but maybe try disabling write caching altogether (for the USB disk)...

Alex

[peterbonge]

Have you tried playng with window's Write Caching policies for the USB disk? It sounds counter-intuitive but maybe try disabling write caching altogether (for the USB disk)...

Writing cache settings are not supported by my USB disk, but I've just tested to switch from "Quick removal" to "Better performance" and now it seems to work much better. So far I haven't noticed any stutters, even with the default SlipSeconds value.

Thank you very much for this hint. I'm wondering why nobody else (incl. me) thought about this.

[ACTCMS]

...So far I haven't noticed any stutters, even with the default SlipSeconds value.

Great - let's hope it fixes the problem permanently...

Alex

[martint123]

. I'm wondering why nobody else (incl. me) thought about this.

Nobody else uses USB drives for mainline system use ??