[mythtv-commits] Ticket #3465: BBC HD on DVB-S dropped video frames. [ Not in mplayer/vnc ]
MythTV
mythtv at cvs.mythtv.org
Wed May 16 09:42:00 UTC 2007
#3465: BBC HD on DVB-S dropped video frames. [ Not in mplayer/vnc ]
-----------------------+----------------------------------------------------
Reporter: anonymous | Owner: ijr
Type: defect | Status: new
Priority: minor | Milestone: unknown
Component: mythtv | Version: unknown
Severity: medium |
-----------------------+----------------------------------------------------
I am seeing dropped frames in mythtv while playing back BBC HD-TV. this is
an h.264 MBAFF stream, so has fairly heavy cpu requirements. I can play
these streams back cleanly on the same machine under windows, and using
vlc/mplayer. Looking at mythfrontend -v playback, frames are being dropped
because the audio is 3 frames out of step with the video. Increasing the
tolerance on this with a quick hack does not solve the problem. I am run
tests on current SVN, using both FFMPEG (h264) and with the coreavc patch
to give me more headroom on the cpu.
Originally posted to mythtv-users.
{{{
PC is core2duo e4300 [overclocked], graphics card nvidia 7300Ls. Cpu
load is recorded as {cpu core0:core1}
Windows2000:
2.7GHz : VLC: ffmpeg: no skiploopfilter: BBC-HD MBAFF h.264: CPU 60%:20%
smooth.
2.7GHz : VLC: ffmpeg: skiploopfilter: BBC-HD MBAFF h.264: CPU 40%:10%
smooth.
2.7GHz : MplayerClassic: coreavc: no skiploopfilter: BBC-HD MBAFF h.264:
CPU 60%:30% smooth.
2.7GHz : MplayerClassic: coreavc: skiploopfilter: BBC-HD MBAFF h.264: CPU
40%:20% smooth.
Ubuntu 7.04. .
2.7GHz : VLC: ffmpeg: no skiploopfilter: BBC-HD MBAFF h.264: CPU 100%:20%
and dropped frames.
2.7GHz : VLC: ffmpeg: skiploopfilter: BBC-HD MBAFF h.264: CPUs 90%:20%
smooth.
2.7GHz : Mythtv: ffmpeg: skiploopfilter: BBC-HD MBAFF h.264: CPU 90%:20%
and dropped frames.
2.7GHz : Mythtv: coreavc: skiploopfilter: BBC-HD MBAFF h.264: CPU 40%:40%
and dropped frames.
So it looks as if I can reduce the quality of the ffmpeg decoding by
using skiploopfilter to not max out the CPU, or use a non-free coreavc
codec. However Mythtv is still doing somthing odd with the Sync between
Audio and Video which is leading to it detecting the audio falling out
of sync with the video, and then dropping video frames to resync.
}}}
--
Ticket URL: <http://svn.mythtv.org/trac/ticket/3465>
MythTV <http://svn.mythtv.org/trac>
MythTV
More information about the mythtv-commits
mailing list