[linux-dvb] Corrupted MPEGs (DVB-C)?

Joachim Steiger roh at hyte.de
Mon Aug 14 23:32:36 CEST 2006


On Mon, Aug 14, 2006 at 08:30:46AM +0200, Thomas Börkel wrote:
> HI!
> 
> Recorded DVB-C mpeg files seem to be somehow corrupted or illegal. I can 
> watch them perfectly with mplayer and MythTV, but skipping/jumping 
> through them causes problems.
> 
> MythTV (using ffmpeg) reports most of the time things like this, but the 
> picture is visually OK:
> [mpeg2video @ 0xb73fc7e4]skipped MB in I frame at 1 29
> [mpeg2video @ 0xb73fc7e4]ac-tex damaged at 0 30
[...]
> 149 DAS 
> VIERTE:762000000:INVERSION_AUTO:6900000:FEC_NONE:QAM_64:2047:2048:1793
> 149 DAS VIERTE: f 762000000, s 6900000, i 2, fec 0, qam 3, v 0x7ff, a 0x800
> status 1f | signal 9696 | snr eded | ber 00195000 | unc ffffffff | 
> FE_HAS_LOCK
> status 1f | signal 9393 | snr eeee | ber 00195000 | unc 00000000 | 
> FE_HAS_LOCK
> status 1f | signal 9393 | snr eded | ber 00195000 | unc 00000000 | 
> FE_HAS_LOCK
> status 1f | signal 9393 | snr eeee | ber 00195000 | unc 00000000 | 
> FE_HAS_LOCK

try to fix your cable tv. the ber is much too high. it should be zero
all the time.
propably you have some bad cable, some defective/wrong dimensioned or
just old amp or splitter between the in-house connection and your card
which generates a lot of phase noise.
such errors are very common and i have only seen very few cable outlets
in the livingrooms of people with no such problems when beeing called in
my time as a tv techie. mostly its much too old cabling equipment
which does not give any visible problems on analog tv, but completely
messes up the qam signals, especially on the higher UHF frequencys (>460
mhz is mostly bad because of in-house cabling which is older than me ;)

if you are willing to track this down you can contact me directly.

--

roh



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