Stuttering problem (1 Viewer)

[Doodles]

In the thread https://forum.team-mediaportal.com/showthread.php?t=11510 about a periodic stuttering in MyTV, we are all seeing a common log entry at the time of the stutter. I wonder if one of you TV engine developers could tell us what it means. In most instances, we get six lines in the log containing the following, but sometimes with diffferent numbers:

2007-01-07 11:48:28.828707 [Info.][MPMain]: VMR9Helper: playing->repaint 3
2007-01-07 11:48:29.375589 [Info.][3]: planescene: PresentSurface() frame:0 enabled:True allowed:False 768x576
2007-01-07 11:48:29.391214 [Info.][MPMain]: VMR9Helper: repaint->playing 1
2007-01-07 11:48:31.422490 [Info.][MPMain]: VMR9Helper: playing->repaint 2
2007-01-07 11:48:31.438115 [Info.][3]: planescene: PresentSurface() frame:0 enabled:True allowed:False 768x576
2007-01-07 11:48:31.469365 [Info.][MPMain]: VMR9Helper: repaint->playing 1

Do you know what sort of event might trigger it?

Any help you can give would be much appreciated.

 

[Taipan]

Do you know what sort of event might trigger it?

I think that those log entries relate to DVB reception and are an indication that the TV signal has been corrupted and those corrupted frames cannot be displayed. The corruption can occur if the TV signal has droped below the lower reception threshold, or some sort of external RF interference has scrambled the data stream (the bit error rate (BER) is excessive for those frames).

DVB signal strength and signal quality can be improved by:-
1. installing a higher gain antenna
2. checking that the antenna is oriented for maximum signal
3. raising the height of the antenna
4. using only quad-shielded coax for the cable from the antenna to the DVB card
5. using only F-type screw connectors
6. minimising the use of splitters, or use powered splitters with neutral or minimal gain
7. judicious use of a mast-head amplifier (use as a last resort as it is possible to have too much signal and get the same effect)

 

[Doodles]

Many thanks Taipan. That give me something to work on.

 

[iamfrank]

Whilst I'd normally agree Taipan, I checked out my signal quality and strength using FusionHDTV, all were above 92% and 22.5dB. FusionHDTV also played perfectly for about 20 hours straight.

WAIT a minute, I can replicate it w00t! It's an intermittent interference. Say for example, someone flicks on and off a light, or a fridge turns on, anything. With my old Meedio or Digitalwatch setup, I used to get a little stutter as everything resynched, probably a result of some interference being caused in the house wiring. On some STB's, you see this as a bit of pixellation. It appears there is a problem with the way MP handles these errors. If I rewind a little bit, it's okay, and just stutters over the error in playback, but if I'm right at the front of the timeshift buffer, it starts stuttering as if it's in a perpetual error state.

Having relayed all that, any ideas how to fix it?

 

[iamfrank]

FusionHDTV also played perfectly for about 20 hours straight.

Sorry, just thought I should clarify this. I didn't watch it for 20 hours straight, so in every likelihood is stuttered or went pixelated. What I meant though was it was "fine" when I came back and checked it.

 

[Taipan]

It's an intermittent interference. Say for example, someone flicks on and off a light, or a fridge turns on, anything. Having relayed all that, any ideas how to fix it?

Yes ...

See points 4, 5 & 6 of my post above - it sounds like the lead from your antenna to the TV card is not very well shielded against interference, or the shield of the leadin is not properly grounded.

This is going to be a trial and error process, but assuming that you already have quad-shielded coax all the way from the antenna to the TV card, the first thing I would try is making sure that the braids (all 4 of them) on the coax are connected together and properly grounded. They are probably grounded at the moment via your TV card to the mains earth and this is where the interference is coming from. As a test, can you run a short temporary wire from the coax shield to a water pipe that goes underground? Or, drive a copper stake into the ground nearby (just outside the window) and connect the coax shield to that? In fact, it sounds like your electrical wiring ground (earth) may be suspect? Or, your PC is not earthed correctly?

If you are not sure what to do, then you might be best to get an electrician or TV antenna installer to fix it for you? I would hate to hear that you managed to fry yourself or the PC ...

 

[iamfrank]

Whilst I agree that physically it's not perfect, I don't really think it would be acceptable to most people that it doesn't handle that intermittent error. All other PVR software I've had had coped with these errors fine, as the problem has always existed. It happened at my old house, and my gf's folks house.

In this case, the cable is brand new quad-shield running pretty much directly down the wall from the antenna above. Dunno about a short wire,, it'd take a really long wire to meet up with a water pipe, same deal with the copper.

I will look at solving the external issues, but how do I get the real one fixed, the software one?

 

[Taipan]

All other PVR software I've had had coped with these errors fine, as the problem has always existed.

I don't think that you can blame MediaPortal - but rather the BDA drivers supplied by your TV card manufacturer. I very much doubt that the other PVR software used BDA drivers - in this case you would be using the FusionHDTV application as a comparison?

how do I get the real one fixed, the software one?

Upgrade to the latest BDA drivers, and if that doesn't fix it, then contact Dvico support for a fix.

 

[iamfrank]

Meedio was using BDA drivers, whilst I'm not saying they're perfect either, I still think the problem lies in MP.

 

[diehard2]

Hi, those error messgages have nothing to do with signal strength. They are related to something happening in the vmr9. That area of the code is not particularly well documented however.