[mythtv-commits] Ticket #3312: Recording kills mythfrontend with Standard decoder but is OK with libmpeg2

[MythTV]

#3312: Recording kills mythfrontend with Standard decoder but is OK with libmpeg2
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 Reporter:  anonymous  |       Owner:  ijr       
     Type:  defect     |      Status:  new       
 Priority:  minor      |   Milestone:  unknown   
Component:  mythtv     |     Version:  0.20-fixes
 Severity:  medium     |  
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 I use 0.20-fixes (ATrpms 0.155 r13228). I have an ATSC recording the
 playback of which, at a certain point during it, is guaranteed to kill
 mythfrontend whether via the preview video window or during actual
 playback. Some facts:

  * The issue only occurs with the Standard (ffmpeg) decoder. It does
 '''not''' happen with libmpeg2.
  * I do not use XvMC.
  * The issue exists at least as far back as ATrpms 0.151.
  * The moment is located about one second after the recording's start.
 Before the recording began, the card had previously been used to record
 from the local PBS affiliate's HD channel, which happens to be off the air
 during daytime hours. During these hours the station displays a blue
 screen with a message saying so.
  * With the libmpeg2 decoder, as the recording starts, this message
 appears; then, as the ATSC card changes to the proper channel, the screen
 turns black for a half second before playback resumes. When advancing
 through this segment frame by frame, there is no such half-second black
 segment (the blue screen immediately shifts, albeit wiht a couple of
 frames of compression blocks, to the video from the correct channel), so I
 presume that the segment causes mythfrontend to hiccup as it figures out
 what to do. (At least a hiccup is better than a full-blown crash.)
  * With the Standard decoder, instead of the black-screen hiccup, the
 screen (whether during full playback or in the preview video window) turns
 green just before the crash.
  * I've seen similar glitches a few other times over the past year when
 recording from the aforementioned PBS HD channel a program that starts
 right when the channel comes back on the air. Usually there's no crash,
 although I can't always be sure I've been using Standard; I've alternated
 between the two many times.

 If desired, I can try to post the problematic recording snippet somewhere.

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Ticket URL: <http://svn.mythtv.org/trac/ticket/3312>
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