[mythtv-users] Remote Mythfrontend Problem

[Steve Milner]

On 15/07/09 11:02, Nick Morrott wrote:
> Those problems still look like being due to a poor quality TV signal.
> Absolute signal strength is not the best artiber of whether you'll
> have a perfect picture. If you run Kaffeine instead of MythTV, do you
> still see vidoe and audio glitches? We need to try and determine where
> the issue lies.

I've not been able to do that yet. I got in late and the backend box is 
outside the kids bedrooms and I can't disturb them lugging kit around.

More to come

> Running MythTV, can you watch LiveTV on the backend system _and_ the
> frontend system and do you get the same problems? Does the LiveTV OSD
> give you a high bit error ratio figure (BER) whilst tuning? Do you see
> lots of mpeg2video errors in the frontend logfiles when playing a
> recording or LiveTV session where you see picture breakup and audio
> glitches? These can all be indications of poor signal strength.
>
> Errors may be like:
>
> 2009-07-15 08:16:45.602 [mpeg2video @ 0x5a3c7b0]ac-tex damaged at 29 25
>

The BER shows 0, but as mentioned elsewhere in this thread some DVB-T 
hardware doesn't shoe BERs

I have run some live TV to a log and here is a sample output.

2009-07-15 21:11:18.938 [mpeg2video @ 0x3b9533f620]00 motion_type at 9 24
2009-07-15 21:11:18.938 [mpeg2video @ 0x3b9533f620]00 motion_type at 1 25
2009-07-15 21:11:18.938 [mpeg2video @ 0x3b9533f620]00 motion_type at 1 26
2009-07-15 21:11:18.938 [mpeg2video @ 0x3b9533f620]00 motion_type at 1 27
2009-07-15 21:11:18.938 [mpeg2video @ 0x3b9533f620]00 motion_type at 6 28
2009-07-15 21:11:18.939 [mpeg2video @ 0x3b9533f620]ac-tex damaged at 21 29
2009-07-15 21:11:18.939 [mpeg2video @ 0x3b9533f620]00 motion_type at 0 30
2009-07-15 21:11:18.939 [mpeg2video @ 0x3b9533f620]00 motion_type at 0 31
2009-07-15 21:11:18.939 [mpeg2video @ 0x3b9533f620]00 motion_type at 0 32
2009-07-15 21:11:18.939 [mpeg2video @ 0x3b9533f620]00 motion_type at 0 33
2009-07-15 21:11:18.939 [mpeg2video @ 0x3b9533f620]00 motion_type at 17 34
2009-07-15 21:11:18.939 [mpeg2video @ 0x3b9533f620]00 motion_type at 0 35
2009-07-15 21:11:24.558 [mpeg2video @ 0x3b9533f620]00 motion_type at 36 12
2009-07-15 21:11:29.755 [mpeg2video @ 0x3b9533f620]slice mismatch
2009-07-15 21:11:29.756 [mpeg2video @ 0x3b9533f620]ac-tex damaged at 3 3
2009-07-15 21:11:29.756 [mpeg2video @ 0x3b9533f620]ac-tex damaged at 0 4
2009-07-15 21:11:29.756 [mpeg2video @ 0x3b9533f620]ac-tex damaged at 4 5
2009-07-15 21:11:29.757 [mpeg2video @ 0x3b9533f620]00 motion_type at 3 6
2009-07-15 21:11:29.757 [mpeg2video @ 0x3b9533f620]ac-tex damaged at 2 7
2009-07-15 21:11:29.757 [mpeg2video @ 0x3b9533f620]00 motion_type at 1 8
2009-07-15 21:11:29.757 [mpeg2video @ 0x3b9533f620]ac-tex damaged at 5 9
2009-07-15 21:11:29.757 [mpeg2video @ 0x3b9533f620]ac-tex damaged at 5 10
2009-07-15 21:11:29.758 [mpeg2video @ 0x3b9533f620]ac-tex damaged at 1 11
2009-07-15 21:11:29.758 [mpeg2video @ 0x3b9533f620]00 motion_type at 7 12
2009-07-15 21:11:29.758 [mpeg2video @ 0x3b9533f620]00 motion_type at 3 13
2009-07-15 21:11:29.758 [mpeg2video @ 0x3b9533f620]00 motion_type at 2 14
2009-07-15 21:11:29.758 [mpeg2video @ 0x3b9533f620]00 motion_type at 5 15
2009-07-15 21:11:29.758 [mpeg2video @ 0x3b9533f620]invalid mb type in P 
Frame at 7 16
2009-07-15 21:11:29.758 [mpeg2video @ 0x3b9533f620]00 motion_type at 2 17
2009-07-15 21:11:29.759 [mpeg2video @ 0x3b9533f620]00 motion_type at 1 18
2009-07-15 21:11:29.759 [mpeg2video @ 0x3b9533f620]00 motion_type at 7 19
2009-07-15 21:11:29.759 [mpeg2video @ 0x3b9533f620]00 motion_type at 2 20
2009-07-15 21:11:29.759 [mpeg2video @ 0x3b9533f620]00 motion_type at 5 21
2009-07-15 21:11:29.759 [mpeg2video @ 0x3b9533f620]00 motion_type at 5 22
2009-07-15 21:11:29.759 [mpeg2video @ 0x3b9533f620]00 motion_type at 7 23
2009-07-15 21:11:29.759 [mpeg2video @ 0x3b9533f620]00 motion_type at 5 24
2009-07-15 21:11:29.760 [mpeg2video @ 0x3b9533f620]00 motion_type at 11 25
2009-07-15 21:11:29.760 [mpeg2video @ 0x3b9533f620]ac-tex damaged at 7 26
2009-07-15 21:11:29.760 [mpeg2video @ 0x3b9533f620]invalid mb type in P 
Frame at 29 27
2009-07-15 21:11:29.760 [mpeg2video @ 0x3b9533f620]00 motion_type at 5 28
2009-07-15 21:11:29.760 [mpeg2video @ 0x3b9533f620]00 motion_type at 2 29
2009-07-15 21:11:29.760 [mpeg2video @ 0x3b9533f620]ac-tex damaged at 1 30
2009-07-15 21:11:29.761 [mpeg2video @ 0x3b9533f620]slice mismatch
2009-07-15 21:11:29.761 [mpeg2video @ 0x3b9533f620]00 motion_type at 13 32
2009-07-15 21:11:29.761 [mpeg2video @ 0x3b9533f620]00 motion_type at 2 33
2009-07-15 21:11:29.761 [mpeg2video @ 0x3b9533f620]00 motion_type at 7 34
2009-07-15 21:11:29.761 [mpeg2video @ 0x3b9533f620]00 motion_type at 4 35
2009-07-15 21:12:03.401 [mpeg2video @ 0x3b9533f620]slice mismatch
2009-07-15 21:12:14.826 [mpeg2video @ 0x3b9533f620]ac-tex damaged at 41 8
2009-07-15 21:12:14.973 [mpeg2video @ 0x3b9533f620]00 motion_type at 17 16
2009-07-15 21:12:25.166 [mpeg2video @ 0x3b9533f620]00 motion_type at 11 34
2009-07-15 21:12:31.490 [mpeg2video @ 0x3b9533f620]invalid cbp at 13 16


The problems like ac-tex damaged, slice mismatch, invalid cbp seem to 
correspond to problems with sound glitches. I have observed some pixel 
artefacts that don't seem to correspond to the entries in the log (I was 
tail -f of the log while watching the TV) but that could be as a result 
of a delay between the log being written and tail passing the output to 
the screen.

I guess this indicates there is something wrong with the TV signal.

I still wonder if there is a problem with the signal being too strong, 
or possibly the passive aerial splitter, but the splitter was in use 
when the box was using the other much smaller aerial.

Regards,

Steve