[mythtv-commits] Ticket #12146: In progress recordings do not always have up to date size/duration

[MythTV]

#12146: In progress recordings do not always have up to date size/duration
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     Reporter:  jyavenard                |      Owner:  jpoet
         Type:  Developer Task           |     Status:  new
     Priority:  minor                    |  Milestone:  unknown
    Component:  MythTV - Video Playback  |    Version:  Unspecified
     Severity:  medium                   |   Keywords:
Ticket locked:  0                        |
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 MythPlayer keeps internally the total number of frames of the video being
 played and its duration.

 Those two values will be updated when the position map is updated by the
 decoder, when it finds an inconsistencies between the position being
 played and its size.

 When the position map is updated, the decoder will call back
 MythPlayer::SetFileLength is called.

 MythPlayer itself can force an update to the position map when calling
 TranslatePositionFrameToMs or TranslatePositionMsToFrame.

 this will call DecoderBase::TranslatePositionFrameToMs which in turn will
 check that the position map has information required. If not it will force
 a call to SyncPositionMap() which in turn will call back
 MythPlayer::SetFileLength

 There is an issue however, in that from time to time, a call to
 TranslatePositionFrameToMs with a total frame count that is completely
 inaccurate doesn't trigger a call to SyncPositionMap() which results in an
 incorrect calculated value.

 This cause failure to seek in an in progress recording (or last liveTV
 program).

 Why would the position map not be refreshed when you attempt to seek into
 a position is the core issue.

 Right now, I've added some workaround in places that required an up to
 date value of MythPlayer::totalFrames: in MythPlayer::CalcMaxFFTime and
 MythPlayer::FindFrame
 but I feel that this is just a dirty work around, and that earlier call to
 TranslatePositionFrameToMs and TranslatePositionFrameToMs should have
 forced an update...

 To test, attached is a patch that makes the backend records 3 minutes
 recordings in liveTV.

 To test, start liveTV and let it go until it jumps to the next program (it
 will occur before 3 minutes). Make sure you are playing live (within a few
 seconds of the actual end position). After about a minute rewind.

 In MythPlayer::Rewind()
 have a breakpoint on
 {{{
         float current = ComputeSecs(framesPlayed, true);
 }}}

 You can verify here that framesPlayed is superior to totalFrames , which
 signal an inconsistency.

 ComputeSecs calls TranslatePositionFrameToMs, which should force an update
 to the position map. but it doesn't

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Ticket URL: <https://code.mythtv.org/trac/ticket/12146>
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