Bad recording dropouts with USB tuners

[nmw01223]

I am not sure if this is truely an Argus bug, but it makes using it problematic. I use a Toshiba Satellite Pro 2GHz dual core, 4GB RAM, 250GB SSD, W7/32bit SP1. Triplestick 292e / August DVB-T210 (both latest drivers) USB receivers, Argus 2.3, Kodi 15.0.

When setup to record via Kodi or the scheduler console the recordings all have a lot of picture breakup and are virtually unuseable, same with either tuner, although the T210 sometimes logs some PCR clock errors, the 292e doesn't - result is the same, though. Generally I set it all up, put the laptop to standby and let it wake itself up when recording is due, though the result is the same if it wasn't in standby, or even if just recording a service directly via the recorder console.

I notice others have similar problems.

Tried lots of things: external powered hub, disabled AV (Kaspersky), Windows updates to manual and killed off W10 nag popup, Windows Media Centre removed (has its own update regime), aerial booster, upping the recorder process CPU priority via task manager, disabling LAN (wireless), changing power options (especially USB). None had any effect. CPU used when recording is typically 10-15%, with 5-10% on the recorder process itself. Nothing (after logging with perfmon and procmon) appears to be going on that should affect it - nothing I could correlate, anyway.

Then I found that if watching live via Kodi, or Live TV (using VLC) in scheduler console the pictures were fine. Then found if watching via Kodi whilst recording - also fine. In fact, if Kodi is just running minimised in the background and doing nothing, the recordings are fine. For example, start recording, 60 secs in start Kodi, 120 secs in stop recording. The first 60 secs will have breakup, the last 60 will not.

Kodi specifically (I think) has nothing to do with it, it is the act of something communicating with the scheduler or recorder services that does it (I assume Kodi probably has a TCP/IP socket connection live). If something is, all is fine, if it isn't, bad picture breakup. Seems therefore to be something to do with process priority, foregound / background processes / possibly instantaneous sleep for power saving.

Having Kodi running is therefore a way of getting good recordings. The problem with that is that after recording, the laptop will not go back into sleep as Kodi is still running.

So, it is a problem, with a workround that sort of works, with issues (the sleep point). Is there something that can be done in the Argus services to sort this out?

[nmw01223]

I have found a possible cause for this, although it is not yet proven.

The default Windows timer period is 15.6mS, some apps increase to get better resolution on timer events, at the cost of increased power / CPU usage. Kodi increases it (1mS), so does Video LAN (5mS), and so does Mozilla Firefox (1mS).

If any of these are running, recording is OK. if they aren't, it isn't.

It may be therefore that the USB receivers are polled rather than event driven (suspect PCI receivers may be different, or at least have more buffering), and the default timer period of 15.6mS does not give enough resolution to provide sufficiently regular polling, thus allowing overruns.

To test this I wrote a dialog app to allow requesting of a 1mS period. When not selected, recording breakup, when selected, no breakup. Limited testing so far, however.

What is needed therefore, if this is really the case, is for a higher resolution timer period to be requested by the Argus recording service while recording is in progress.