[mythtv-commits] Ticket #9140: AC3 passthrough causes accelerated OSX playback

MythTV mythtv at cvs.mythtv.org
Sat Oct 23 22:25:05 UTC 2010


#9140: AC3 passthrough causes accelerated OSX playback
-----------------------------------+----------------------------------------
     Reporter:  myth@…             |       Owner:  nigel     
         Type:  defect             |      Status:  new       
     Priority:  minor              |   Milestone:  0.25      
    Component:  Ports - OSX        |     Version:  Trunk Head
     Severity:  medium             |    Keywords:            
Ticket locked:  0                  |  
-----------------------------------+----------------------------------------
 Digital audio passthrough can cause the OSX frontend to speed up playback
 of the video and audio by a large factor.

 This has been previously discussed in #5552 .  It's 'locked', hence this
 new ticket and hopes I'm not breaching protocol, as the wiki does not
 mention locks.

 I observed this with svn rev 26959 on Snow Leopard 10.6.4 running on a Mac
 Pro.  It happened after I changed channels twice while watching LiveTV
 (Chicago, HDHomerun on broadcast networks).  Switching between channels
 was enough to trigger the bug, as I used no other controls.  I attach two
 logfiles...one showing {{{verbose=most}}} from the frontend during the
 action, and another showing {{{verbose=all}}} from the backend.

 Perhaps it is notable that I see several messages like this:

 {{{Video is 3.17581 frames behind audio (too slow), dropping frame to
 catch up.}}}

 and

 {{{Waited 100ms for video buffers}}}


 A typical snippet from the backend log read as follows

 {{{
 2010-10-23 16:38:18.034 XDS: failed CRC 845/1230
 2010-10-23 16:38:18.034 AFD: video timecode 6782378273 6782381276
 6782378273 75359758 75359725
 2010-10-23 16:38:18.034
 RingBuf(/Volumes/Brobits/TV/1111_20101023160000.mpg): ReadPriv(..32768,
 normal) @983040 -- begin
 2010-10-23 16:38:18.034
 RingBuf(/Volumes/Brobits/TV/1111_20101023160000.mpg): ReadPriv(..32768,
 normal) -- copying data
 2010-10-23 16:38:18.034
 RingBuf(/Volumes/Brobits/TV/1111_20101023160000.mpg): ReadPriv(..32768,
 normal) -- checksum 4739
 2010-10-23 16:38:18.034 GetNextFreeFrame() served a busy frame D.
 Dropping. UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU
 2010-10-23 16:38:18.034 GetNextFreeFrame() is getting a busy frame P.
 UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU
 2010-10-23 16:38:18.041 AFD: video timecode 6782381276 6782384279
 6782381276 75359791 75359758
 2010-10-23 16:38:18.051
 RingBuf(/Volumes/Brobits/TV/1111_20101023160000.mpg): ReadPriv(..32768,
 normal) @1015808 -- begin
 2010-10-23 16:38:18.051
 RingBuf(/Volumes/Brobits/TV/1111_20101023160000.mpg): ReadPriv(..32768,
 normal) -- copying data
 2010-10-23 16:38:18.051
 RingBuf(/Volumes/Brobits/TV/1111_20101023160000.mpg): ReadPriv(..32768,
 normal) -- checksum 38213
 2010-10-23 16:38:18.059 AFD: video timecode 6782384279 6782387282
 6782384279 75359825 75359791
 2010-10-23 16:38:18.059 AFD: audio timecode 6782329810 6782329810 75359220
 75359252
 2010-10-23 16:38:18.060 AFD: audio timecode 6782332690 6782332690 75359252
 75359284
 2010-10-23 16:38:18.060 AFD: audio timecode 6782335570 6782335570 75359284
 75359316
 2010-10-23 16:38:18.060 AFD: audio timecode 6782338450 6782338450 75359316
 75359348
 2010-10-23 16:38:18.060 AFD: audio timecode 6782341330 6782341330 75359348
 75359380
 2010-10-23 16:38:18.060
 RingBuf(/Volumes/Brobits/TV/1111_20101023160000.mpg): ReadPriv(..32768,
 normal) @1048576 -- begin
 2010-10-23 16:38:18.060
 RingBuf(/Volumes/Brobits/TV/1111_20101023160000.mpg): ReadPriv(..32768,
 normal) -- copying data
 2010-10-23 16:38:18.060
 RingBuf(/Volumes/Brobits/TV/1111_20101023160000.mpg): ReadPriv(..32768,
 normal) -- checksum 34553
 2010-10-23 16:38:18.060
 RingBuf(/Volumes/Brobits/TV/1111_20101023160000.mpg): safe_read(... at 0,
 1048576) -- begin
 2010-10-23 16:38:18.061 GetNextFreeFrame() served a busy frame M.
 Dropping. UUULUUUUUUUUUUUUUUUUUUUUUUUUUUU
 2010-10-23 16:38:18.061 GetNextFreeFrame() is getting a busy frame P.
 UUULUUUUUUUUUUUUUUUUUUUUUUUUUUU
 2010-10-23 16:38:18.061
 RingBuf(/Volumes/Brobits/TV/1111_20101023160000.mpg): safe_read(... at 0,
 1048576) -> 1048576
 2010-10-23 16:38:18.061
 RingBuf(/Volumes/Brobits/TV/1111_20101023160000.mpg): rbwpos += 1024K
 requested 1024K in read
 }}}

 Please indicate if there are any other diagnostics that may be valuable:
 myth [at] boonstra [dt] org .

-- 
Ticket URL: <http://svn.mythtv.org/trac/ticket/9140>
MythTV <http://www.mythtv.org/>
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