[mythtv-commits] Ticket #8500: more accurate audio timestamps

MythTV mythtv at cvs.mythtv.org
Sun May 30 14:44:27 UTC 2010

#8500: more accurate audio timestamps
 Reporter:  markspieth             |       Owner:  jyavenard 
     Type:  patch                  |      Status:  new       
 Priority:  minor                  |   Milestone:  unknown   
Component:  MythTV - Audio Output  |     Version:  Trunk Head
 Severity:  medium                 |     Mlocked:  0         

Comment(by markspieth):

 understood. however the part that needs to be lockless is only modifying
 the ringbuffer pointers. the storage in the other process components is
 only modified in AddSamples. Thus these latencies are static and can be
 excluded from the lockless component as they can be precalculated. This
 also makes GetAudiotime faster as it doesnt have to include these
 latencies. audbuf_timecode becomes the top of the ringbuffer, not the
 latest timecode of the added audio data.

 1.3-1.4 secs is marignal avsync delay for 6ch audio out. with the increase
 of bytes per sample to 4 (float32 due to processing enabled,
 upmix+timestretch), all that the increase does is maintain the worst case
 storage. it doesnt work properly otherwise. could go to a dynamic. the
 number is also that to make sure it is divisible by all the possible
 alternatives, including 8 ch out.

 for smooth sync to work correctly, the race is very important.

Ticket URL: <http://svn.mythtv.org/trac/ticket/8500#comment:3>
MythTV <http://www.mythtv.org/>

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