[mythtv-users] Frame Drop problems??

[David Madsen]

Let me know how your next conversion goes.  I switched my ext3 file system
over to writeback mode, we'll see if that helps at all.  I would like to
figure out what is causing this.  I also noticed something else interesting
after I made the first post.  all of those duplicate frame messages happen
spaced exactly 10 frames apart.  I don't know what (if any) significance
that may have, but interesting none the less..

Dave

----- Original Message ----- 
From: "mojo" <mojospam at thegeekclub.net>
To: "Discussion about mythtv" <mythtv-users at snowman.net>
Sent: Wednesday, July 09, 2003 3:55 AM
Subject: Re: [mythtv-users] Frame Drop problems??


> David Madsen wrote:
>
> > Recently I have been noticing something strange happening in the backend
> > while recording.  I convert some the recorded files into mpegs for
archiving
> > by using mencoder to reencode the video.  while running mencoder about
> > halfway through the file it runs into a chunk of the .nuv file and dumps
out
> > a whole bunch of these messages, which I believe to be parts of the file
> > where the backend has dropped video frames.
> >
> > 1 duplicate frame(s)!
> > Pos:1731.3s  51807f (46%) 219fps Trem:   4min 1529mb  A-V:-0.067
[3333:96]
> > 1 duplicate frame(s)!
> > Pos:1731.6s  51817f (46%) 219fps Trem:   4min 1529mb  A-V:-0.067
[3333:96]
> > 1 duplicate frame(s)!
> > Pos:1732.0s  51827f (46%) 219fps Trem:   4min 1529mb  A-V:-0.067
[3333:96]
> > 1 duplicate frame(s)!
> > Pos:1732.4s  51837f (46%) 219fps Trem:   4min 1529mb  A-V:-0.067
[3333:96]
> > 1 duplicate frame(s)!
> > Pos:1732.7s  51847f (46%) 219fps Trem:   4min 1528mb  A-V:-0.067
[3333:96]
> > 1 duplicate frame(s)!
> > Pos:1733.1s  51857f (46%) 219fps Trem:   4min 1528mb  A-V:-0.067
[3333:96]
> >
> >
> > The strange thing about this is that there are no dropped frames in any
> > other part of the file, just consolidated to one group about halfway
through
> > recording a 1 hour show.  I have looked through the system and there are
no
> > other crons or anything starting up that would cause something like this
to
> > happen. It also happens no matter what time of the day it is recording.
I'm
> > wondering if anyone else has noticed something similar?  in the
resulting
> > file after mencoder is finished there is a section of the file where the
> > missing frames are visible and causes the audio to go out of sync for a
few
> > minutes.  I am recording at 640x480, 3300 bps  on a Athlon XP 2000+.
the
> > CPU stays around 35-40% utilized while recording.  DMA is turned on and
> > hdparm reports about 40MB/s.  I can't see what would be causing it to
drop
> > frames.  Any ideas?
> >
> > David Madsen
> >
>
> i have been getting similar results when converting to divx .avi's with
> a 2-pass mencoder run... audio is slightly out of sync... for me, the
> duplicate frame errors are not centralized to that one part of the file
> though, they are scattered throughout most of the file...  i was using
> mpeg4 640x480 2200 kbps, vhq, v4mv, on an athlon xp 1700.. and was
> pushing my cpu up to 90% or so, so i just lowered my settings
> considerably and am going to wait for the next recording to convert and
> test... my mencoder conversion settings dont seem to make much
> difference on the audio sync... from my understanding (searching
> mplayers mailing list archives) those duplicate frame errors are
> definitely bad news and im guessing are whats causing my problems.
>
> Sean
>
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