[mythtv-commits] Ticket #6395: AVFormatDecoder Language/codec detection improvements

MythTV mythtv at cvs.mythtv.org
Sun Jul 26 01:21:12 UTC 2009

#6395: AVFormatDecoder Language/codec detection improvements
 Reporter:  robert.mcnamara at gmail.com  |        Owner:  danielk 
     Type:  enhancement                |       Status:  assigned
 Priority:  trivial                    |    Milestone:  unknown 
Component:  MythTV - Video Playback    |      Version:  head    
 Severity:  low                        |   Resolution:          
  Mlocked:  0                          |  

Comment(by robert.mcnamara at gmail.com):

 New patch is more or less identical to the last one, but it corrects a
 flaw in the original code where DTS would never be selected as the audio
 track unless DTS passthrough was enabled.  I can only conclude that at the
 time it was written, ffmpeg could not properly decode DTS audio in
 software.  This is possible now and works nicely.

 The new version of the patch now happily selects the DTS-HD MA tracks in
 Blu ray material, as it should (it will generally be the primary audio
 track).  In testing with all my Blu ray material (50ish disks) and HD-DVD
 stuff too (about the same), the primary audio track is correctly chosen in
 every case.  The one exception is LPCM audio in blu ray, which is not
 correctly parsed in mpegts.c yet.  When it's possible, I'll submit a

 This patch doesn't cause this bug, but it does highlight it-- Myth will
 not handle 8 channel audio.  At all.  It just plays white noise/static and
 halves the video framerate.  An LPCM track or a TrueHD 7.1 track will
 produce white noise.  The reason the white noise issue didn't exist in
 TrueHD tracks before the ffmpeg sync is because the prior version of the
 MLP decoder decoded two channels and tossed out the rest.  Since it now
 decodes all channels, this limitation of myth is highlighted.  It might be
 nice to create a similar workaround that ignores the last couple channels
 until myth has 7.1 capabilities.

Ticket URL: <http://svn.mythtv.org/trac/ticket/6395#comment:3>
MythTV <http://www.mythtv.org/>

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