#10045 HIGH 1.5-sof: XO-1.5 Record audio/video are out of sync with each other

[Zarro Boogs per Child]

#10045: XO-1.5 Record audio/video are out of sync with each other
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           Reporter:  wad              |       Owner:  dsd                              
               Type:  defect           |      Status:  new                              
           Priority:  high             |   Milestone:  1.5-software-update              
          Component:  record-activity  |     Version:  Development build as of this date
         Resolution:                   |    Keywords:  camera record XO-1.5             
        Next_action:  diagnose         |    Verified:  0                                
Deployment_affected:                   |   Blockedby:                                   
           Blocking:                   |  
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Comment(by Quozl):

 A significant improvement in video recording is achieved by moving the
 instance directory for the Record activity off the SD card.

 The result was no significant pauses in video motion during recording, and
 a much more predictable A/V latency.

 The downside is restricted recording time.

 This suggests that the current problems with recording are due to the SD
 writes.  See #9688 (terrible SD write performance: wontfix), #9995
 (optimise kernel write block size), and #10112 (GUI freezes on fsync).

 While this is not the best way of doing it, this is the method I used:

  * start Record,
  * copy the directory to a large enough tmpfs,
  {{{
 cd .sugar/default
 rsync -a org.laptop.RecordActivity /dev/shm
 }}}
  * remove the old directory and create a symlink,
  {{{
 rm -rf org.laptop.RecordActivity && \
 ln -s /dev/shm/org.laptop.RecordActivity
 }}}
  * continue using the Record activity.

 (This symlink persists until removed ... and since /dev/shm is empty next
 boot the Record activity will fail to start.)

-- 
Ticket URL: <http://dev.laptop.org/ticket/10045#comment:25>
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