[mythtv-users] Recording Playback Length

[Robert Longbottom]

On 4 Feb 2011, at 08:02 AM, "Michael T. Dean" <mtdean at thirdcontact.com> wrote:

> On 02/04/2011 01:56 AM, Robert Longbottom wrote:
>> On 4 Feb 2011, at 06:00 AM, john.baab wrote:
>>> When playing back my recordings the time in the OSD often doesn't
>>> match with the actual running time of the recording itself.  Example
>>> Community from last night, recorded from 8:00 - 8:31.
>>> 
>>> Running ffmpeg on this recording I see:
>>> Duration: 00:30:57.31, start: 56537.388856, bitrate: 15027 kb/s
>>> 
>>> From my logs the recording time is correct:
>>> 2011-01-20 20:00:02.759 Started recording: Community:"Asian Population
>>> Studies": channel 7081 on cardid 1, sourceid 7
>>> 2011-01-20 20:31:00.936 Finished recording Community "Asian Population
>>> Studies": channel 7081
>>> 
>>> But when I watch it, MythTV's OSD says the recording is 25:57.  If I
>>> go ahead and watch the recording the entire thing is there, so
>>> playback is unaffected.  Rebuilding the seek table for the recording
>>> doesn't help.  Any ideas?
>> No ideas, but just a "me too". I've just upgraded to the latest 0.24-fixes and I now see this problem on all my recordings.
> 
> It has to do with variable frame rates and repeat pictures and the fact that MythTV currently just uses a quick approximation to get the total length of the recording.
> 
>>  Previously it was just on the HD channels that I was seeing it. It breaks bookmarks and skipping around for me which is annoying, but I've not had chance to investigate any further yet.  I'll try and do some digging this weekend if I get the chance.
> 
> If you means bookmarks take you to the wrong place and/or skipping around takes forever, that's broken seek tables.  (And you should probably update to the most-current -fixes build.)

Yes, bookmarks were definitely taking me to the wrong place last night, but skipping forwards from the start of the recording was working ok. 

Sounds like I need to rebuild my seek tables then. Is there an easy way to do this for all recordings?  I did a very quick search for this last night, but it was late and I didn't find anything straight away. 

I don't know if it make a difference, but I was seeing the problems while watching an in-progress recording. 

> The only effect that the above-mentioned approximation could have is that instead of skipping forward 10s, you may skip forward 11.5s; or instead of 30s, you may go 34.7s; or instead of 3m, you may go 3m 28s.  However, bookmarks would always take you right back to where you set them, since we set them--and seek to them--based on frame number.

That make sense. I'll do some more investigating tonight and see what's going on. 

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