[mythtv-commits] Ticket #5749: Internal player stutters on 720p content

MythTV mythtv at cvs.mythtv.org
Sat Sep 27 21:25:27 UTC 2008

#5749: Internal player stutters on 720p content
 Reporter:  zgeggy2k at yahoo.com  |       Owner:  ijr       
     Type:  defect              |      Status:  new       
 Priority:  major               |   Milestone:  unknown   
Component:  Video Playback      |     Version:  0.21-fixes
 Severity:  medium              |     Mlocked:  0         

 I recently moved to a new HTPC so I decided to upgrade my Fedora 8 install
 of mythtv to Fedora 9.
 I currently have this installed on fedora 9: mythtv-0.21-192.fc9.i386
 (along with the rest of the pkgs) from livna (pkgs from atrpms exhibit the
 same behaviour).

 The new HTPC is based on a Gigabyte Mobo GA-73PVM-S2H, which I connect to
 my receiver via HDMI and SPDIF. I'd get rid of SPDIF (and use solely HDMI)
 if there was support for Audio over HDMI from nvidia, but since there
 isn't, I'll stick to 2 cables for now.
 The box has 2 Gigs of RAM, core2duo E7200... enough to handle HD I think
 (especially since it's mpeg2, not h264... read below).

 Anyway: I am experiencing issues with playback of some content. This
 content is recorded through an HD Homerun dual tuner box. With some
 interlaced content, it seems the player tries to set the playback rate at
 ~30fps and that works.

 With progressive content (720p I think), I get lots of "WriteAudio: buffer
 underrun" errors, and the content is unwatchable. Video slows to a crawl,
 sound goes sporadically out to the receiver so I do hear some audio (for
 half a second or so) randomly during playback. It seems like (from the
 log) that the player wants to hook to 60fps (well 59.something).

 Now, I tried to see if it wasn't a sound config issue (got rid of
 pulseaudio, just using alsa now), and an nvidia issue (for video
 sync'ing)... didn't make a difference.
 What tells me it's mythtv specific is that I can play this file
 beautifully out of my recordings directory directly with mplayer. No
 stuttering, low CPU usage... no problem with any recording with mplayer.

 I've played around with mythtv options: extra audio buffering, etc... no
 joy! Even increased alsa buffers from 64 to 1024 in /proc -> nothing.

 So I'm stuck, and it seems so is this guy: URL:http://www.gossamer-

 Will attach cases (logs+samples) for a successful playback (interlaced)
 and a broken one.
 Let me know if there's any other tests I can run.


 Output of mythfrontend --version:

 Please include all output in bug reports.
 MythTV Version   : 0.21-7.lvn9
 MythTV Branch    : tags/release-0-21
 Library API      : 0.21.20080304-1
 Network Protocol : 40
 Options compiled in:
  linux release using_oss using_alsa using_arts using_jack using_backend
 using_dbox2 using_dvb using_firewire using_frontend using_hdhomerun
 using_iptv using_ivtv using_joystick_menu using_lirc using_opengl_vsync
 using_opengl_video using_v4l using_x11 using_xrandr using_xv using_xvmc
 using_xvmcw using_xvmc_vld using_bindings_perl using_bindings_python
 using_opengl using_ffmpeg_threads using_libavc_5_3 using_live

Ticket URL: <http://svn.mythtv.org/trac/ticket/5749>
MythTV <http://www.mythtv.org/>

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