[mythtv-users] Glitches in firewire capture from DCT-6200

Sat Dec 17 15:31:48 EST 2005

Steve, running the commands you and curtis specified:

plugctl -n 2 opcr[0].channel=63
plugctl -n 2 opcr[0].bcast_connection=1

greatly improves my firewire reliability.  However, I still find it almost
unusable due to some slowdown/stuttering in the image.  (I also have a
PVR-250 which works flawlessly)  I know it's not my network, so I was very
curious to try out the data_rate command you listed above, thinking that it
might fix this issue.  (plugctl -n 2 opcr[0].data_rate=3)

Running this command and then plugreport shows that the data_rate variable
does get set to 3, (before it was zero), HOWEVER, as soon as I begin to
record a show or watch live TV, it immediately gets set back to zero.  You
mentioned that you run this through a cron job every hour, although I'm
finding that if I try to set the data_rate back to 3 while something is
recording, it immediately freezes and stops recording.

Any other tricks or ideas to somehow keep this setting  at 3?  (or anything
greater than zero)

On 12/16/05, David Rudder <drig at noses.org> wrote:
>
> Are you sure this isn't a drive-speed issue?  Check hdparm -v
> /dev/<device>.  Also, make sure you have at least a 7200 RPM drive.
> The dct-6200 will send out an mpeg stream.  I think MythTV just copies
> it to disk.  So, there's very little CPU or memory involved.
>
> You can try running test-mpeg2 (from the libiec61883 package).  It
> outputs the raw mpeg stream from the 6200.  If it gets the same
> corruption you see in myth, then you know it's not a myth issue.
> test-mpeg2 > file.mpg
> wait maybe 30 seconds, then hit ctrl-c.  mplayer file.mpg should display
> the file.
>
> -Dave
>
> Azmat wrote:
>
> >I've been using this script in a cron job for the last week, but I'm
> >still seeing glitching.  Its mostly occurring at the start of a show
> >and then clears up in the middle.  Is it possible that I might need to
> >use a faster processor or bump up my RAM?  Right now I'm running an
> >Athlon XP 2400+ with 1G of RAM.  Thanks in advance for the help.
> >
> >Azmat
> >
> >On 12/9/05, Steve Adeff <adeffs at gmail.com> wrote:
> >
> >
> >>there was a thread a while back regarding this. You can search on
> Gossamer for
> >>more info. basically you want to run this bash script. It will set the
> p2p or
> >>broadcast connection to 1 depending on what your machine will use. From
> what
> >>I've found bcast is prefered when available, which is why it comes
> second
> >>(since its one or the other) p2p is sometimes only available and when
> this is
> >>the case its fine. data_rate doesn't need to be 3, but it increases
> speed if
> >>your using firewire for capture and not just channel changing. I have it
> run
> >>before mythbackend starts when I run it via init.d and I've found it
> resets
> >>sometimes so I run it hourly as a cron job.
> >>
> >>oh, and the -n # is which node it is. In case you have more than one
> firewire
> >>connection have it run for each connection as well.
> >>
> >>#!/bin/bash
> >>plugctl -n 2 opcr[0].channel=63
> >>plugctl -n 2 opcr[0].n_p2p_connections=1
> >>plugctl -n 2 opcr[0].bcast_connection=1
> >>plugctl -n 2 opcr[0].data_rate=3
> >>
> >>--
> >>Steve
> >>
> >>On Friday 09 December 2005 14:52, Azmat wrote:
> >>
> >>
> >>>Here's my plugreport output:
> >>>Host Adapter 0
> >>>==============
> >>>
> >>>Node 0 GUID 0x0000d10080357942
> >>>------------------------------
> >>>libiec61883 error: error reading oMPR
> >>>libiec61883 error: error reading iMPR
> >>>
> >>>Node 1 GUID 0x4279358080357942
> >>>------------------------------
> >>>libiec61883 error: error reading oMPR
> >>>libiec61883 error: error reading iMPR
> >>>
> >>>Node 2 GUID 0x000f9ffffe103008
> >>>------------------------------
> >>>oMPR n_plugs=1, data_rate=2, bcast_channel=63
> >>>oPCR[0] online=1, bcast_connection=0, n_p2p_connections=0
> >>>        channel=63, data_rate=0, overhead_id=0, payload=376
> >>>iMPR n_plugs=0, data_rate=2
> >>>
> >>>On 12/9/05, Steve Adeff <adeffs at gmail.com> wrote:
> >>>
> >>>
> >>>>On Friday 09 December 2005 12:44, Azmat wrote:
> >>>>
> >>>>
> >>>>>Hi,
> >>>>>
> >>>>>My mythtv system is running on an AMD Athlon XP 2400+ (2 GHz) with 1G
> >>>>>RAM, a PVR-350 and firewire capture from my Motorola DCT-6200 cable
> >>>>>box.  Whenever I do firewire capture from the box through Myth, the
> >>>>>recording exhibits a audio/video glitching.  The picture will
> >>>>>momentarily become pixelated and there will be a brief skip.  I can
> >>>>>tell the glitch is in the recording because when I rewind and
> playback
> >>>>>it is reproducible.  There is no pattern or regularity to the
> >>>>>glitching.  Sometimes it will be at the start of the show and will
> >>>>>disappear in the middle, only to reappear later.  It doesn't prevent
> >>>>>me from recording shows, but is just become a huge annoyance that I'd
> >>>>>like to take care of.  Does anyone have any idea what might be wrong?
> >>>>>Do you think a faster processor would help?
> >>>>>
> >>>>>Thanks in advance,
> >>>>>
> >>>>>Azmat
> >>>>>
> >>>>>
> >>>>run plugreport and paste the output.
> >>>>
> >>>>--
> >>>>Steve
> >>>>
> >>>>
> >>>--
> >>>
> >>>
> >>>Azmat
> >>>
> >>>
> >
> >
> >--
> >
> >
> >Azmat
> >_______________________________________________
> >mythtv-users mailing list
> >mythtv-users at mythtv.org
> >http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> >
> >
>
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