[vdr] Re: AV-Sync lost ???

[Wolfgang Fiesel <fie@iis.fhg.de>]

Klaus Schmidinger wrote:

> Axel Gruber wrote:
> >
> > Hello List
> >
> > Iīm totaly frustrated my VDR works now since nearly 1 year realy perfekt.
> >
> > -PIII800
> > - 4 DVB-S Cardīs
> > 6* 80GB Maxtor Harddrive
> >
> > But since 1 Week i often have SYNC-Lost between Audio and video in my Recordings.
> > For Example Yesterday Recording of MASH - sync lost after 40 Minutes....
> > I thought that this could happen because of CPU overflow (2 or more Recordings and a Playback)
> >
> > But this morning i have searched the log again and i found a recording stared at 6.30 am
> > with the same Problem. (no playback or other recording at the same time)
> >
> > I donīt have any idea why this happen now...
> >
> > Here is a part of the Log from today:
> >
> > Jan 18 07:49:40 tvserver vdr[18677]: recording to '/video0/Ich_beide_ampersandonlyencodedforie_sie/2002-01-18.06:30.99.99.rec/003.vdr'
>
> Hey, thats funny: "ampersandonlyencodedforie" - ROTFL
>
> > Jan 18 07:49:40 tvserver vdr[18677]: creating directory /video4/Ich_beide_ampersandonlyencodedforie_sie
> > Jan 18 07:49:40 tvserver vdr[18677]: creating directory /video4/Ich_beide_ampersandonlyencodedforie_sie/2002-01-18.06:30.99.99.rec
> > Jan 18 07:49:51 tvserver vdr[18678]: ERROR (dvbapi.c,585): DVB driver buffer overflow
> > Jan 18 07:50:02 tvserver vdr[18678]: ERROR (dvbapi.c,585): DVB driver buffer overflow
> >
> > This is not the only one - i have now 5 Recordings on disk wich are out of sync and
> > not watchable.
> >
> > Here is another Error-Log wich i never have seen in Log-File:
> >
> > Jan 17 22:20:07 tvserver vdr[11060]: read incomplete section - seclen = 1365, n = 502
> > Jan 17 22:20:07 tvserver vdr[11060]: read incomplete section - seclen = 1175, n = 190
> > Jan 17 22:20:07 tvserver vdr[11060]: read incomplete section - seclen = 1125, n = 53
> > Jan 17 22:20:07 tvserver vdr[11060]: read incomplete section - seclen = 99, n = 42
> > Jan 17 22:20:07 tvserver vdr[11060]: read incomplete section - seclen = 1582, n = 54
> > Jan 17 22:20:07 tvserver vdr[11060]: read incomplete section - seclen = 592, n = 455
> > Jan 17 22:20:07 tvserver vdr[11060]: read incomplete section - seclen = 1125, n = 134
> > Jan 17 22:20:07 tvserver vdr[11060]: read incomplete section - seclen = 1123, n = 988
> > Jan 17 22:20:07 tvserver vdr[11060]: read incomplete section - seclen = 1346, n = 24
> > Jan 17 22:20:07 tvserver vdr[11060]: read incomplete section - seclen = 428, n = 70
> > Jan 17 22:20:07 tvserver vdr[11060]: read incomplete section - seclen = 2162, n = 355
> >
> > So - if anyone have a Idea what i can do.... - please let me know....
> >
> > PS: I have asked Klaus about this - but he notīt have a Idea - he sayed i could
> > set a higher Buffersice - no i have set 10 but still same problem..
> >
> > CU
> >
> > Axel
>
> My guess would be that your harddisk performance has gone down dramatically.
> Can't say why, though, but a "DVB driver buffer overflow" normally indicates
> that VDR can't write the data to disk fast enough. Have you tried running
> a disk performance test?
>

Hello,

only some remarks from my side, because during my setup time my VDR system had shown similar problems:

7*80GByte Maxtor
ASUS A7V133 (with Promise controller on board)
1.2 GHz Athlon
2 DVB-S cards from Haupagge (full and Nova)
SuSE 7.2 (first 2.4.4 -> 2.4.16)
VDR 0.99pre1
latest DVB driver (06.01.2002)

My problem was that most of my recordings were out of synch and interrupted by a glitch sounds. This happens mostly if a time shift
operation was done. (read and write simultanously). Single recording was fine.
First idea was to enable DMA operation by kernel and hdparm, but no success.
A disk performance test (bonnie) said about 12-24MByte. Thats fine.
Afterwards I updated the kernel because of the Southbridge workaround of KT133A.
My impression was that synch problem happens now much seldon but was not 100% error free.

In the case that operation failed the log message says that I/O error happens at IDE interface and tried to reset the IDE interface (Uups).
Now I was sure that hardware related problems on the IDE interface were the reason. Therefore I reduced the transfer rate of the harddisks
from UDMA5 to UDMA2 (33 MHZ).
Now I don't have any problems more (since 2 weeks - meanwhile 260GByte recordings)
I suppose that my longer 80pin IDE cable (blue round shielded from KM) is not 100% sure for 100MHz bus speed of UDMA5.
I use a big tower chassis therefore upper harddisks could not be connected with "standard" length IDE cable.

Otherwise UDMA2 is fast enough for MPEG2 system data rates (only  ~2-3 MBytes/s).

You should try to reduce IDE speed by <hdparm -X 66>, perhaps it helps. Did you changed the environment of your VDR recorder (microwave,
other computers) ?

Wolfi