[mythtv-users] Video and Audio Stutter

[Calin Brabandt]

Mike,

Have you tried disabling MythTV audio?  You may find
the video playback to be smooth, as I found.  Hoever,
I get stuttering with live or recordings playback. 
Xine is smoother (or much smoother)! 

I still have not found a solution to my list inquiry
of a few days ago.  What errors to you see when you do
mythfrontend -v playback?

-Cal

Date: Tue, 4 Jul 2006 14:16:41 -0700 (PDT)
From: Calin Brabandt <cbrabandt at yahoo.com>
Subject: [mythtv-users] Stuttering only when audio
enabled (dropping
	frames).
To: mythtv-users at mythtv.org
Message-ID:
<20060704211641.23965.qmail at web32204.mail.mud.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1

I'm running Via Openchrome XvMC on a P4M800Pro
motherboard.  When I set the audio device to /dev/null
(or other nonsense), playback is smooth.  When I set
it to ALSA:default or /dev/dsp, Myth drops frames on
playback (live TV or recordings).  It also drops
frames with the standard (non-Via XvMC) decoding
setting.

I've tried all the audio options available in
mythfrontend Utilities/Setup >> Setup to no avail (and
pretty much every other option too!)

Here's the output from mythfrontend -v playback

With ALSA:
http://home.comcast.net/~calinb/myth_audio

Near the bottom, you'll see the 

"2006-07-04 13:15:00.916 NVP: Video is 3.05305 frames
ahead of audio, dropping frame."

which goes on continuously.  (This was a short run).

With /dev/null:
http://home.comcast.net/~calinb/myth_null

there are no frame drops once playback stabilizes.

Also, without HT on FC5-32, HDTV results in cpu loads 
around 60% with 3.2GHz Prescott.  This seems high but
it appears XvMC is being used, based on the output
above.

Any suggestions are much appreciated.

-Cal

> Date: Thu, 6 Jul 2006 05:55:47 -0400
> From: "Michael A Weber" <mweberjunk01 at wowway.com>
> Subject: [mythtv-users] Video and Audio Stutter
> To: <mythtv-users at mythtv.org>
> Message-ID:
<01dd01c6a0e2$5b4cf120$644ba8c0 at mikeplaptop>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> I have been scouring the list archives to find a
solution to my 
> problem, but
> I have not found anything with promise.
> 
>  
> 
> I had a functioning Myth system on 0.18, however my
audio was a bit of 
> a
> problem with the version of the ivtv driver I had at
the time.  So, I
> eventually decided to upgrade the ivtv driver (which
was to fix the bad
> audio), and that required a kernel update among
other things to meet
> dependency requirements.
> 
>  
> 
> So, I went to kernel 2.6.16-1.2111 under FC4,
updated my nvidia fx5200
> driver to version 8762, ivtv to 0.6.2, myth
components to 0.19-128 or 
> -124
> depending on the availability, and after a bit of
headache with 
> permissions,
> I got LiveTV functioning again, ALMOST.
> 
>  
> 
> The audio and video on LiveTV (and most likely on
recordings as well) 
> seem
> to "stutter" with a bit of a repeat of frames and
sound and then try to
> catch back up to the source every 5 seconds or so. 
It's as if the 
> stream is
> not being played back at the correct speed and it
lags behind; then the
> audio/video is "reset" back to the current position
in the stream and 
> frames
> are dropped to make it happen.
> 
>  
> 
> I have tried XvMC and all the other settings for
offloading the video 
> to the
> hardware; I have tried the setting for "use video
signal for timebase"
> setting or however that reads; I have tried what
people suggested in 
> earlier
> posts of pausing the live video and waiting a few
seconds, then 
> playing;
> unfortunately, nothing makes it any better.
> 
>  
> 
> But, the really sad thing is that if I simply cat
the device port to a 
> .mpg
> file for a while, then play it back with mplayer or
xine, it's perfect.  
> No
> stuttering, nada.
> 
>  
> 
> I'm at a total loss, and I have refrained from
watching live tv for 
> weeks
> since it's quite unbearable.  Does anyone have any
ideas as to the root
> cause of this problem?  Or, does anyone have any
suggestions on a 
> potential
> fix?
> 
>  
> 
> Mike


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