[mythtv-commits] Ticket #4940: Audio/Video Sync. Reproducible. Internal player issue.

[MythTV]

#4940: Audio/Video Sync. Reproducible. Internal player issue.
----------------------------+-----------------------------------------------
 Reporter:  mark at onnow.net  |       Owner:  ijr       
     Type:  defect          |      Status:  new       
 Priority:  critical        |   Milestone:  unknown   
Component:  mythtv          |     Version:  0.21-fixes
 Severity:  high            |     Mlocked:  0         
----------------------------+-----------------------------------------------
 From a very long series of list conversations.  Others can reproduce this
 problem as well.

 Internal player has audio about 1 second(ish) behind video.
 Capture is from firewire on DCT-6200.

 HD capture from this same device is fine.  This is SD capture.

 After recommendations to try playing the file with ffplay:

 I have also tried to enter a ticket with ffmpeg ( this behavior is the
 same when playing file in ffplay ), but ffmpeg said they would not accept
 ticket unless I was running latest SVN.  The ffmpeg libraries that are
 used in Myth Internal player are "old" in the words of the ffmpeg list.

 Mplayer and xine play this fine BTW.

 To get the sample file:
 wget this file below.

 http://onnow.net/syncprob.mpg

 My Internal player has audio sync problems.
 mplayer is fine with the file.
 The Internal player audio is off.
 Please, try it for yourself.
 It starts with 3 commercials. The third one is two kids talking.  It
 is obvious that the audio is off with the internal player.


 I'm having the same audio problem when playing your file back with my
 system. Here's my log:

 [mythtv at livingroom ~]$ ffplay syncprob.mpg
 FFplay version SVN-r12135, Copyright (c) 2003-2008 Fabrice Bellard,
 et
 al.
  configuration: --prefix=/usr --libdir=/usr/lib --shlibdir=/usr/lib
 --mandir=/usr/share/man --enable-shared --enable-gpl --enable-pp --
 enable-swscaler --enable-pthreads --enable-x11grab --enable-liba52 --
 enable-liba52bin --disable-avisynth --disable-libamr-nb --disable-
 libamr-wb --enable-libdc1394 --enable-libfaac --enable-libfaad --
 enable-libfaadbin --enable-libgsm --enable-libmp3lame --enable-
 libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --
 extra-
 cflags=-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -
 fstack-
 protector --param=ssp-buffer-size=4 -m32 -march=i386 -mtune=generic -
 fasynchronous-unwind-tables --disable-strip
  libavutil version: 49.6.0
  libavcodec version: 51.50.1
  libavformat version: 52.7.0
  libavdevice version: 52.0.0
  built on Feb 18 2008 20:01:30, gcc: 4.1.2 20070925 (Red Hat
 4.1.2-33)
 No accelerated IMDCT transform found

 Any chance you want to try it in MythTV as a recording--use
 myth.rebuilddatabase.pl or whatever--with a valid seektable?  Create
 the
 seektable with:

 mythtranscode --mpeg2 --buildindex --allkeys -c 9999 -s '2008-03-11
 16:00:00'

 (fixing chanid and starttime to equal whatever you used when you
 imported it).  Played perfectly for me with a good seektable.  See my
 post in the "Sound a second behind video" thread.
 Will do.

 Actually, that question was meant for Brad.  I just want someone else to
 confirm that it plays without A/V sync issues whenwe have a good
 seektable.

  Question though.
 This file was a recording.  Named "1023_20080311101559.mpg"
 Can I just choose transcode on it and do the same thing?

 For you, Mark, follow the instructions in my post on the other thread.

  Perhaps I
 should transcode all files after recording?
 I am wondering what a permanent fix could be.  This came from a TV
 recoding originally.
 Or do I need to run another transcode command?

 Thanks for the help.  What is the root cause of this problem though?
 ffmpeg or something else?

 The jury is still out...

 Mike
 -----

 I have deleted seek table and then run the transcode, same results.
 Seems related to strictly the internal player. ffmpeg?

 If i take that recording and move it to my video directory, Internal
 player is still having sync issues.  That would seem to remove the
 seektable variable from this.

 -----
 MythTV uses ffmpeg's libraries, but it uses a copy built specifically
 for MythTV.  Therefore, it's not using the libraries that you have
 installed on your system, but it's own "internal" copy of the libs.

 ffplay gave the same behavior.
 I was using the latest ATRPMS version of .21.

 Right.  Because we are using ffmpeg libs.  Just not ones that you can
 change.

 Mike

 ---------

 Happy to provide more info to get this fixed.
 Live TV is unwatchable with this. Playback is essentially the same.  The
 only way to watch is with another player such as mplayer etc...

-- 
Ticket URL: <http://svn.mythtv.org/trac/ticket/4940>
MythTV <http://www.mythtv.org/>
MythTV