[mythtv-users] The dreaded pre-buffering pause

[Taylor Ralph]

On Thu, Apr 1, 2010 at 9:10 PM, Yan Seiner <yan at seiner.com> wrote:
> I'm trying to track down why my Atom 330 system keeps pausing with
> pre-buffering pauses when playing h.264 video.  It works just fine with lavc
> encoded video.
>
> First of all, I'm running latest 0.23:
>
> Please include all output in bug reports.
> MythTV Version   : 23892
> MythTV Branch    : branches/release-0-23-fixes
> Network Protocol : 56
> Library API      : 0.23.20100314-1
> QT Version       : 4.5.0
> Options compiled in:
> linux release using_oss using_alsa using_backend using_dvb using_frontend
> using_hdhomerun using_hdpvr using_iptv using_ivtv using_joystick_menu
> using_lirc using_mheg using_opengl_video using_opengl_vsync using_qtdbus
> using_qtwebkit using_v4l using_x11 using_xrandr using_xv using_xvmc
> using_xvmc_vld using_bindings_perl using_bindings_python using_opengl
> using_ffmpeg_threads using_live using_mheg
>
> Here's the output from mythfrontend.  I've highlighted the two lines that I
> think may be a source of the problem.  I'd appreciate any help on this.  The
> system runs fine, mythfrontend uses 55% CPU (which is consistent with the
> Atom 330's 2+2 CPU core structure - dual core + hyperthreading) and overall
> the system shows as 83% idle when playing back material.
>
> 2010-04-01 17:40:49.960 Current MythTV Schema Version (DBSchemaVer): 1254
> 2010-04-01 17:40:51.601 Registering Internal as a media playback plugin.
> 2010-04-01 17:40:52.268 Current MythMusic Schema Version (MusicDBSchemaVer):
> 1017
> 2010-04-01 17:40:52.389 MonitorRegisterExtensions(0x40,
> mp3,mp2,ogg,oga,flac,wma,wav,ac3,oma,omg,atp,ra,dts,aac,m4a,aa3,tta,mka,aiff,swa,wv)
> 2010-04-01 17:40:52.487 Current MythVideo Schema Version
> (mythvideo.DBSchemaVer): 1032
> 2010-04-01 17:40:52.551 XMLParseBase: Loading window theme from
> /usr/local/share/mythtv/themes/Terra/menu-ui.xml
> 2010-04-01 17:40:52.909 Loading menu theme from
> /usr/local/share/mythtv/themes/defaultmenu//mainmenu.xml
> 2010-04-01 17:40:52.916 Found mainmenu.xml for theme 'Terra'
> 2010-04-01 17:40:52.987 MythContext: Connecting to backend server:
> 127.0.0.1:6543 (try 1 of 1)
> 2010-04-01 17:40:53.009 Using protocol version 56
> 2010-04-01 17:56:04.928 Loading menu theme from
> /usr/local/share/mythtv/themes/defaultmenu//library.xml
> 2010-04-01 17:56:07.510 XMLParseBase: Loading window theme from
> /usr/local/share/mythtv/themes/Terra/video-ui.xml
> 2010-04-01 17:56:07.732 New DB connection, total: 2
> 2010-04-01 17:56:07.733 Connected to database 'mythconverg' at host:
> localhost
> 2010-04-01 17:56:10.948 XMLParseBase: Loading window theme from
> /usr/local/share/mythtv/themes/Terra/video-ui.xml
> 2010-04-01 17:56:13.441 TV: Attempting to change from None to WatchingVideo
> 2010-04-01 17:56:14.321 AFD: Opened codec 0x98b53c0, id(H264) type(Video)
> 2010-04-01 17:56:14.321 AFD: codec MP3 has 2 channels
> 2010-04-01 17:56:14.321 AFD: Opened codec 0x98b1fc0, id(MP3) type(Audio)
> 2010-04-01 17:56:15.258 Opening audio device 'default'. ch 2(2) sr 48000
> (reenc 0)
> 2010-04-01 17:56:15.276 Opening ALSA audio device 'default'.
>
> +++++++++++++++++++++++++++++++++++++++++++++++++
>
> 2010-04-01 17:56:15.281 ALSA, Warning: mmap not available, attempting to
> fall back to slow writes.
>
> +++++++++++++++++++++++++++++++++++++++++++++++++
>
> 2010-04-01 17:56:15.345 Mixer unable to find control PCM
> 2010-04-01 17:56:15.345 Mixer unable to find control PCM
>
> ****************************************************************************
>
> 2010-04-01 17:56:15.445 VideoOutputXv: Desired video renderer 'xvmc-blit'
> not available.
>           codec 'H.264' makes 'xv-blit,xshm,xlib,' available, using
> 'xv-blit' instead.
>
> ****************************************************************************
>

You need to select 'VDPAU Normal' as your playback profile in
Setup->TV Settings->Playback Profiles(3/8). The Atom isn't strong
enough to handle software decode for many cases.

Regards.

--
Taylor