[mythtv] Too much EIT activity causing defective recordings

John Pilkington johnpilk222 at gmail.com
Tue Jul 31 22:51:09 UTC 2018


Hi;  I'm running Master under SL7, recording UK SD DVB-T material via 
one PCI single-tuner device and one twin-tuner usb dongle.

Bus 001 Device 002: ID 1b80:e409 Afatech IT9137FN Dual DVB-T [KWorld 
UB499-2T]

Around 9 July my Project-X-based mythDVBcut logs started reporting 
multiple AV sync corrections of up to a second in recordings from the 
usb tuners.  The change occurred after I rescanned my transports 
following the Wimbledon special tennis coverage;  I'm fairly sure I made 
other 'minor' changes in the multirec and EIT configs too.

Today I realised that the defects were often around 5 minutes apart, and 
EIT scanning seemed a possible culprit.  I have now unchecked the boxes 
for usb open-on-demand and active-EIT-scan, and it looks as if the 
recording defects have largely gone.

In the past I probably haven't taken as much notice of the EIT settings 
as I should have done, but the recent defects were much worse than I had 
seen before and I think some of the recent code changes must have been 
implicated.

John P

Below is a Project-X log resync section from an affected recording. 
This should be just a few lines, with no resync required.

{{{

Input File 0:  '/mnt/dat2/RSG3/1004_20180723195800.ts.old' 
(1,149,983,780 bytes)
-> Filetype is TS (generic PES Container)

<demux log snipped>

++> Mpg Audio: PID 0x044E / PesID 0xC0 / SubID 0x00 :
-> check CRC of AC-3 / MPEG-Audio L1,2
-> remove CRC in MPEG-Audio L1,2
-> add frames
-> Audio PTS: first packet 08:48:35.071, last packet 09:48:52.207
-> Video PTS: start 1.GOP 08:48:41.439, end last GOP 09:48:41.999
-> adjusting audio at video-timeline
-> src_audio: MPEG-1, Layer2, 48000Hz, stereo, 192kbps, noCRC @ 00:00:00.000
!> 5 frame(s) (120ms) inserted @ 00:02:28.608
!> missing syncword @  6527233, @ 00:04:08.064
!> found syncword @ 6528384
!> 22 frame(s) (528ms) inserted @ 00:04:08.064
!> missing syncword @  6528961, @ 00:04:08.592
!> found syncword @ 6529352
!> missing syncword @  14213193, @ 00:09:27.840
!> found syncword @ 14213560
!> missing syncword @  14214137, @ 00:09:27.864
!> found syncword @ 14214344
!> 4 frame(s) (96ms) inserted @ 00:09:27.864
!> missing syncword @  29606793, @ 00:16:02.448
!> found syncword @ 29607000
!> 1 frame(s) (24ms) inserted @ 00:16:02.448
!> 19 frame(s) (456ms) inserted @ 00:21:21.144
!> missing syncword @  45001753, @ 00:26:40.656
!> found syncword @ 45001960
!> 23 frame(s) (552ms) inserted @ 00:26:40.680
!> missing syncword @  52701353, @ 00:27:54.144
!> found syncword @ 52701536
!> missing syncword @  52702689, @ 00:27:54.192
!> found syncword @ 52703080
!> 20 frame(s) (480ms) inserted @ 00:27:54.192
!> missing syncword @  60403625, @ 00:33:14.592
!> found syncword @ 60404248
!> 17 frame(s) (408ms) inserted @ 00:33:14.616
!> missing syncword @  68103065, @ 00:38:34.344
!> found syncword @ 68103712
!> 17 frame(s) (408ms) inserted @ 00:38:34.344
!> missing syncword @  68120993, @ 00:38:34.752
!> found syncword @ 68121960
!> 2 frame(s) (48ms) inserted @ 00:38:34.752
!> missing syncword @  75797161, @ 00:39:47.760
!> found syncword @ 75797944
!> missing syncword @  83496185, @ 00:45:07.344
!> found syncword @ 83496968
!> 21 frame(s) (504ms) inserted @ 00:45:07.416
!> missing syncword @  83504457, @ 00:45:07.920
!> found syncword @ 83505080
!> missing syncword @  83566137, @ 00:45:09.816
!> found syncword @ 83566920
!> 2 frame(s) (48ms) inserted @ 00:45:09.816
!> 2 frame(s) (48ms) inserted @ 00:45:09.960
audio frames: wri-pre-skip-ins-add 117813-0-0-155-0 @ 00:47:07.512 done...
---> new File: '/home/john/MythTmp/tempcut19417.mp2'

summary of created media files:
.Video (m2v):	70688 Frames	00:47:07.520	 
'/home/john/MythTmp/tempcut19417.m2v'
Audio 00 (mp2):	117813 Frames	00:47:07.512	0-0-155-0 
'/home/john/MythTmp/tempcut19417.mp2'
=> 775,195,585 bytes written...
-> we have 139 warnings/errors.

}}}


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