[mythtv-commits] Ticket #10833: DVB-T radio programs time display and cutlist problems

[MythTV]

#10833: DVB-T radio programs time display and cutlist problems
-------------------------------------+-------------------------------------
 Reporter:  John Veness              |           Type:  Bug Report -
  <John.Veness.mythtv@…>             |  General
   Status:  new                      |       Priority:  minor
Milestone:  unknown                  |      Component:  MythTV - General
  Version:  0.25-fixes               |       Severity:  medium
 Keywords:                           |  Ticket locked:  0
-------------------------------------+-------------------------------------
 Playback of UK DVB-T (Freeview) radio programs exhibit two problems which
 I think are related, hence me putting it into one ticket. These are
 recordings that contain audio only (and MHEG) but no video.

 Problem 1:

 If you press the key to skip forward 10 minutes, the OSD will show that
 you have gone forward 10 minutes, but in actual fact, you will have gone
 forward 12 minutes (this has been determined by listening to the recording
 on a straight playthrough and noting what happens at certain times).

 So for example, on a 35 minute recording, you can do the following:
 - start playback from the start
 - press to skip forward 10 minutes, the OSD will say approx 10:00 but I
 know that this is actually playing something that happens approx 12
 minutes into the recording
 - press to skip forward another 10 minutes, the OSD will say approx 20:00
 but I know that this is actually playing something that happens approx 24
 minutes into the recording
 - press to skip forward another 10 minutes, the OSD will briefly show
 approx 29:10 and play a burst of sound which I know actually happens at
 the end of the recording (i.e. at 35 minutes) before exiting

 You'll notice that 29:10 is approximately 50/60ths of 35 minutes.

 Problem 2:

 On DVB-T recordings that I recorded in 0.24, and edited in 0.24 (that is,
 I added a cut at the beginning and a cut at the end to trim the recording
 down to just the actual show), when I play them back in 0.25, without
 skipping through the recording, the following happens:

 - Interestingly, it seems to start in the correct place, i.e. at the start
 of the actual show a couple of minutes into the recording
 - But playback will stop early, several minutes from the end

 To work round this, I have to remove the cut point at the end of the
 recording, and restart playback and try to navigate to the correct place.
 I don't have timestamps for this issue, but I'm pretty certain that
 playback is stopping early because Myth "thinks" it is reaching the frame
 at which the end cut point exists 50/60ths too early.

 Some observations:

 Firstly, note that if you play back one of these recordings with no
 cutlist points defined, and without skipping forward or back, everything
 seems fine - you will hear the entire recording OK and if you bring up the
 OSD, the time display looks fine from start to finish.

 When pressing to skip forward or back 10 minutes, the skip doesn't take
 effect immediately. There is a few seconds gap before it skips and the OSD
 pops up. This only happens on DVB-T radio recordings, not DVB-T TV
 recordings. It "feels" as it Myth is having a problem trying to find the
 correct place to skip to.

 This wasn't a problem in 0.24 or earlier versions. The same recordings
 that I made in 0.24 played fine in that version, but exhibit the problems
 mentioned above in 0.25. The problems are observed both on old (0.24 era)
 and new (0.25 era) recordings.

 Without wishing to be too presumptuous, I *think* the problem is that Myth
 is treating the recordings as if at 60fps, rather than 50fps, although as
 there is no actual video on these recordings maybe that statement doesn't
 quite make sense.

 I can upload a sample UK DVB-T radio recording and logs if desired.

-- 
Ticket URL: <http://code.mythtv.org/trac/ticket/10833>
MythTV <http://code.mythtv.org/trac>
MythTV Media Center