[mythtv-users] TiVo Convert Experience - HDTV Video Card Recommendation

Brian Walter blwalter at gmail.com
Thu May 3 15:36:19 UTC 2007

Brad Fuller wrote:
> Brian L. Walter wrote:
>> I'm kinda in the same boat.  We have 3 DirecTivos, and a Myth setup in 
>> the bedroom.  Right now, I'd advise against giving up the DirecTivos for 
>> now, as Myth has some recording stability issues.
> I don't have any recording stability issues with Myth. Recording is a
> piece of cake.  Sometimes I have problems with playing an HD stream on
> my FE/BE while recording HD and SD programs simultaneously. But, that's
> because of my system. You might indicate your problems here and maybe
> someone can help you.
Right at the moment, I'm tracking down two issues:

1) IVTV DMA errors, which, based on past posts, are related to IVTV 
interrupt bugs.  It sounds like the developer for IVTV is currently in 
the process of moving, so, no new development  is forth coming for a 
bit.  The solution for now, monitor the logs religiously, and when the 
dma errors stack up enough, reboot the  backend.  I'm also 
investigating, based on information from the Wiki, upping the latency 
time of the disk sub system.  However, that is going to require a phone 
call to Asus, as no one here knows how, and I've got no response from 
either the forums at Asus, or, from an emailed request to Asus support.

2) About 85 percent of HD recordings either are corrupted (mostly still 
watchable, but, with lots of artifacts), or, start out great, then, just 
as the episode reaches the denouement,  start getting  artifacts and 
corruption.   I  just  *love* hearing the wife  going 'oh no...have to 
watch it downstairs'....

3) Not exactly stability related...just an annoyance factor - Fast 
Forward and Rewind stopped working in the most recent rpm updates (hangs 
on prebuffering ).  The frontend and backend are on a gigabit network, 
with about 800mbits through put, so, I'm not convinced it's 
communications related.  On standard broadcast stuff, I can *usually* 
get 3x to work...but...that's almost not worth the effort, so, skipahead 
and skipback are becoming our favorite buttons:)

I've watched the loads, and nothing seems out of the ordinary.  I'm  
using  an Asus  M2N-SLI-Deluxe with  AMD  Athlon X2 4000+ with 2.5gig 
memory.  During recording, neither processor drops much, if at all, 
below 50% idle.  I've taken to running the backend at nice -1, just to 
see if any impact.  Also, sql and job queue have been moved off the 
system to remote machines.

Interestingly enough, I have artifacts and some corruption when 
watching/recording non-HD broadcasts from digital sources (HDHR).  This 
is why I'm looking for a way to capture a stream from the HDHR to disk, 
the equivalent of 'cat /dev/video0 > test.mpg' for the PVR's. (yes, I 
know it's not *that* simple...but...you get my drift).

Now, having said all *that*, yesterday I ran a small stress test - 
recorded 2 digital streams, and 3 analog - in *that* instance, 
everything worked.  So, I'm trying to isolate one issue at a time, and 
trying various stress tests to see if I can isolate just where the 
problems are coming from.

If anyone else has gone through a similar setup, with similar issues, 
I'd be glad to hear what solutions worked for you...


More information about the mythtv-users mailing list