[mythtv-users] Fwd: Playback of recordings end prematurely

[Nick Morrott]

On 28/08/2008, Michael T. Dean <mtdean at thirdcontact.com> wrote:
> On 08/27/2008 07:12 PM, Julian Cerruti wrote:
>  > I wonder if someone could give me some advice on how to go about
>  > resolving this issue.
>  >
>  > For a long while (I don't know when this started, probably about a
>  > year ago) all the recordings from shows end earlier than their real
>  > length when played from the mythTV "watch recordings" page. For
>  > example, when I record a program of 30 minutes length, playback shows
>  > a duration of 23:47. I noticed that the recording is indeed longer
>  > than that, for example, by playing back the .mpg file externally using
>  > mplayer. Also, depending on how playback is configured in mythTV, it
>  > would continue playing past 23:47, only the progress counter would
>  > stop moving (it remains in 23:47 of 23:47) and also many navigation
>  > functions (FFWD, RWD) are lost. Also is commercial auto-skip. In fact:
>  > I have a slight suspicion that in many cases, commercial flagging is
>  > not worken as well as it could because of this.
>  >
>  > A couple more details: I notice that the "end time" reported by the
>  > mythTV player is suspiciously similar for similar length recordings.
>  > Something like: 30 mins -> 23:47; 1hr -> 47:58; etc. Also, I verified
>  > the guide data is reasonably OK (this time discrepancy doesn't seem to
>  > come from there). I am currently running mythtv 0.21 from mythbuntu
>  > 8.04.1 out-of-the-box. I use a Hauppauge 500 with ivtv 1.1.0. Only
>  > unusual setting is that because of my location (Argentina) I'm using
>  > Pal-Nc and a custom-written XMLTV grabber.
>  >
>  > Any advice on how to go about diagnosing this or tips to try to fix it
>  > would be greatly appreciated.
>
>
> The approach Myth uses to calculate duration of the recordings is
>  imprecise with certain types of shows (i.e. shows broadcast with one
>  frame rate while part--such as commercials--use another).  The "issue"
>  is purely cosmetic but fixing it properly is a /lot/ of work, so fixing
>  it has been very low priority (for the couple of years the plan has been
>  in place to fix it).

Mike,

Out of interest, do you know if in-stream rate changing for TV
broadcasts routinely occurs all over the world, or is limited to
certian markets (29.97 vs 23.97 vs 59.94 vs 60 etc)?

Julian's original post made me wonder whether the 30 minute recording
had its length calculated using one framerate but was actually
recorded at another in its (near) entireity, giving the wildly
inaccurate programme timing.

Nick
-- 
Nick Morrott

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