[AG-TECH] Audio and Video Syncronization

Will, Rodger (R.) rwill1 at ford.com
Tue Jun 26 20:13:01 CDT 2001

Some rat packet loss is occurring (not a lot).  Using Opensound.com on a soundbaster of some sort.

I am sure that our time is not synced up, even internally.

-----Original Message-----
From: Bob Olson [mailto:olson at mcs.anl.gov]
Sent: Tuesday, June 26, 2001 9:06 PM
To: Will, Rodger (R.)
Cc: 'Bob Huebert'; Ag-Tech (E-mail)
Subject: RE: [AG-TECH] Audio and Video Syncronization

Unfortunately, configuring NTP won't cause A/V synch to get better.

Do you see loss on the audio or video? Which way does the synch slip?
Which audio card are you using, and with what drivers (opensound.com or
linux kernel)?

ANy other sites that have this probelm as well, please chime in. This is
something we haven't seen here at the ANL nodes.


 On Tue, 26 Jun 2001, Will, Rodger (R.) wrote:

> Thanks. However, I need point to an internal time source until our firewall is configured to pass ntp traffic. If all av machines are pointing to the same timeserver internally, will we be OK for internal grid sessions?
> -----Original Message-----
> From: Bob Huebert [mailto:huebert at arsc.edu]
> Sent: Tuesday, June 26, 2001 8:37 PM
> To: Will, Rodger (R.); Ag-Tech (E-mail)
> Subject: Re: [AG-TECH] Audio and Video Syncronization
> At 7:58 PM -0400 6/26/01, Will, Rodger (R wrote:
> >What can cause Audio and Video Syncronization problems between 
> >nodes?  Our nodes always seem to drift some over time.
> >
> >Does NTP need to be configured on all boxes to prevent this?
> Yes. NTP on your audio and video machines should be pointing to 
> ntp-1.accessgrid.org. Running the install script on the linux boxes 
> should have set this up for you. Ours looks like this:
> --begin /etc/ntp.conf
> server	ntp-1.accessgrid.org
> driftfile	/etc/ntp.drift
> --end
> -bob
> -- 
> _______________________________________________________________________
> Bob Huebert                                 email: huebert at arsc.edu
> HPC Visualization Systems Analyst           voice: (907) 474-5751
> Arctic Region Supercomputing Center           FAX: (907) 474-5494
> University of Alaska Fairbanks                WWW: http://www.arsc.edu/

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