[mythtv-commits] Ticket #12004: Short seeks intolerably slow with HDPVR and vdpau

[MythTV]

#12004: Short seeks intolerably slow with HDPVR and vdpau
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     Reporter:  mythtv@…              |      Owner:
         Type:  Bug Report - General  |     Status:  new
     Priority:  minor                 |  Milestone:  unknown
    Component:  MythTV - General      |    Version:  0.27-fixes
     Severity:  medium                |   Keywords:
Ticket locked:  0                     |
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 I have my frontend (running 0.27 from atrpms) configured with 30 second
 forward seeks, and 5 second sticky backwards seeks.  Seeking forwards or
 backwards 5 seconds takes way too long, sometimes a few seconds.  I
 believe this is caused by the changes in
 4d0bbbe1e54aaa91abbd233b7e5a1a48103462f2 (Remove the "Seek to exact frame"
 setting.) combined with HDPVR putting keyframes 4 seconds apart and vdpau
 taking a long time to decode frames.

 For a 5 second seek, the chance of finding a keyframe in an HDPVR stream
 within 10% of the seek (+/- .5 seconds) is small, so it almost always ends
 up starting from the previous keyframe and then decoding up to 3 seconds
 of frames, which seems to take a few seconds with the vdpau decoder.  An
 easy fix (suggested by jpoet in #11882) is to change the
 kInaccuracyDefault from 0.1 to 0.5, which for a 5 second seek will look in
 the range 2.5-7.5 seconds and will always find a keyframe on an HDPVR
 stream.  I've attached a patch to do that.

 Other ideas:
 Change the seek accuracy to be a constant 5 seconds

 Mark the vdpau decoder as being slow, and use that flag to determine how
 aggressive to be about forcing seeks to exact keyframes.

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Ticket URL: <http://code.mythtv.org/trac/ticket/12004>
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