Unuseable recordings due to dropouts

The built-in ARGUS TV recorder for digital TV
nmw01223
Posts: 18
Joined: Sun Aug 09, 2015 9:48 am

Unuseable recordings due to dropouts

Post by nmw01223 » Fri Sep 11, 2015 10:11 am

I've already tried to get some help on this with no replies (see 29/8/15). Basically, TV recordings drop out all the time and are mainly unuseable. Sometimes the corruption is light (but always there) and it is watchable, sometimes it is so bad it is totally unwatchable. Similar dropouts on live TV viewed via Kodi. Most testing is done with manual service recording to minimise how much s/w is involved, but also be scheduler console recording (starting from standby).

The system is a Toshiba Satellite pro laptop dual core 2GHz, W7 SP1, 4GB RAM, 250GB SSD disk, latest Argus TV, Kodi 15.0, originally an August DVB-T210 USB single channel tuner, now replaced by a PCTV triplestick 292e (all latest drivers).

I have tried:
- killing off AV (Kaspersky).
- setting Windows autoupdate to manual.
- removing Windows media centre (which seems to have it's own update regime).
- killing the Windows 10 'please install me' update.
- Using an external hub (D-Link) for consistent USB power.
- Swapping from the DVB-T210 to the 292e (only ever one at a time).
- Doubling the TV buffer size, no of TV buffers, record buffer size in the recorder config (without really knowing what affects what).
- Using an aerial amplifier, no change and anyway the TV and old Topfield PVR manage just fine.

Nothing has any real effect. Nothing in the task manager tasks list seems to correlate either, and I've also tried recording various parameters using perfmon but couldn't correlate it with errors. The only slight trend is that possibly there are more errors when it has woken from standby (recording a schedule set up in the scheduler console) than when recorded from the recorder console service, or from the Kodi UI. Ie the difference between a background task and foreground - but it is very difficult to be sure, both will have errors.

Recording CPU load is typically 10-15% overall, of which 5-10% is the Argus recorder process.

The DVB-T210 used to put detected PCR errors into the log, the 292e doesn't, but picture breakup is very similar. Basically there's nothing in the log with the 292e - just record started, record ended.

I'm at my wits end, cannot think of anything else to try. I am assuming it is latency and buffer overflow servicing the h/w receiver of some form. It is completely unuseable and I'm about to give up on Argus and try some other s/w, maybe MediaPortal, or possibly dump the whole project and fork out for a newer boxed PVR.

However, before I do that, are there any suggestions on what I can try to resolve this? Argus is a really nicely structured bit of s/w - if only I could get it to work.

nmw01223
Posts: 18
Joined: Sun Aug 09, 2015 9:48 am

Unuseable recordings due to dropouts - extra info

Post by nmw01223 » Fri Sep 11, 2015 1:40 pm

Carried out further testing and slightly in contradiction to previous have found, fairly consistently, that
- record started from Kodi (select program, start recording) and get good quality recording
- record started from record console (direct service manual record) or scheduler console (EPG) and get bad quality recording

This seems to me to point to something to do with foreground/background processes and thread priority. (Whatever thread priority is in use, it is prioritised differently in the foreground on Windows).

nmw01223
Posts: 18
Joined: Sun Aug 09, 2015 9:48 am

Unuseable recordings due to dropouts - extra info 2

Post by nmw01223 » Sat Sep 12, 2015 6:20 pm

Some more information on this.

Start a recording from the Argus TV scheduler console EPG (some current running program) Approximately 60 seconds in just start the Kodi app (windowed, minimise it). 120 seconds in abort the recording from scheduler console.

When playing it back, it will have all sorts of breakup for the first 60 seconds, then about the time Kodi was started, it all cleans up and the rest is OK.

Somehow the act of just running Kodi as a foreground task appears to do this, even though Kodi is not directly involved in this recording.

nmw01223
Posts: 18
Joined: Sun Aug 09, 2015 9:48 am

Re: Unuseable recordings due to dropouts

Post by nmw01223 » Sat Oct 17, 2015 10:41 am

Further investigation shows (not conclusively yet) that changing the power option plan from balanced to high performance (or even within balanced just changing the processor power management minimum process state to 100% - the high performance setting, normally 5%) has the same effect.

Actually somewhere between 50 and 75% appears to be the requirement as there is some (less) breakup at 50%, none at 75% on this particular platform.

However (a) not done a long recording yet to prove this and (b) it clearly isn't what Kodi (or VideoLAN, or anything video related, even a displayed web page with video on it) does, because if I watch the CPU speed with CPU-Z (http://www.cpuid.com/softwares/cpu-z.html)
- on the normal balanced plan setting it varies from 797-2100MHz,
- on high performance or similar as above, it sticks at 2100MHz
- but with Kodi running and the balanced plan (which as stated does record fine) the range is still 797-2100MHz

So, Kodi, VideoLAN etc are doing something else to the system state.

logifuse
Posts: 234
Joined: Wed Oct 12, 2011 8:17 am

Re: Unuseable recordings due to dropouts

Post by logifuse » Sun Oct 18, 2015 12:38 am

CPU power switching was a big issue years ago (talking 6 or 7+) on AMD CPUs, but it only impacted playback, not the recording/stream itself.

nmw01223
Posts: 18
Joined: Sun Aug 09, 2015 9:48 am

Possible solution - Unuseable recordings due to dropouts

Post by nmw01223 » Sun Oct 18, 2015 5:26 pm

Thanks for your comment, but think I might have found the answer to this, though still testing.

Turns out high power modes helped a bit, but did not fully solve it.

For full details see General >> Bug Reports 'Bad recording dropouts with USB tuners', but in summary it appears to be due to Windows default timer resolution of 15.6mS. If it is increased to a higher resolution (1-5mS) - and all those apps do exactly that - the recordings seem OK, if it isn't they aren't. Probably it does not give sufficient resolution to handle the data stream regularly enough.

If it is correct, I am hoping maybe a small change could be made to a future Argus Recorder to up the resolution while recording? Alternatively bigger buffering instead, but it depends what is actually overruning (software buffer or chipset).

Meanwhile I'll have to see if I can figure out how to write a small app or service that detects recording in progress and ups the resolution temporarily.

nmw01223
Posts: 18
Joined: Sun Aug 09, 2015 9:48 am

Re: Unuseable recordings due to dropouts

Post by nmw01223 » Mon Feb 01, 2016 8:59 pm

I have now written a simple tray app for Windows if anyone wants it. E&OE.

doggy
Posts: 2
Joined: Sun Mar 27, 2016 3:11 pm

Re: Unuseable recordings due to dropouts

Post by doggy » Sun Mar 27, 2016 3:19 pm

I have the same problem, recordings full of errors, live TV works fine.

Funny thing is it worked for years with the same hardware, but after a HD crash and reinstall, I have the problem.

Did the timer turn out to be the problem?

noerden
Posts: 10
Joined: Mon May 16, 2011 5:32 pm

Re: Unuseable recordings due to dropouts

Post by noerden » Sun Jun 19, 2016 2:12 pm

Hi there
I have started encountering the same problem, it first started last year - but now i cannot record any program without stuttering after ~1min. Livetv is perfect.

doggy
Posts: 2
Joined: Sun Mar 27, 2016 3:11 pm

Re: Unuseable recordings due to dropouts

Post by doggy » Tue Jul 12, 2016 2:20 pm

I can confirm that it is the timer.
I've used this tool: https://vvvv.org/contribution/windows-system-timer-tool and have not have any problems since.
A simple .bat is used launching the tool at startup.

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