[mythtv-users] watching mkv movies causes pausing problems

Raymond Wagner raymond at wagnerrp.com
Sun Nov 27 22:38:12 UTC 2011

On 11/27/2011 16:27, Doug Lytle wrote:
> Taylor Ralph wrote:
>> Sorry but it's looking like after 0.25. Unfortunately I don't have the
>> time right now.
> That's fine, I was just curious.  Off to look up how to rebuild my seek
> tables!

Those seek tables don't do what you think they do.  When you build a 
seektable for storage in the database, you are mapping keyframes to 
physical locations in the file.  That way, when you are seeking to a 
given frame, you can just jump straight to the nearest keyframe, and 
start playback immediately, rather than waste network bandwidth 
searching for it.  You still need an independent mechanism by which to 
map a time to a given frame count, which is where the reported framerate 
and basic arithmatic come into play.

When you play a telecined DVD, the content is encoded as 24fps 
progressive, but flagged with a 2:3 pulldown and reported as 30fps.  A 
standard player applies the pulldown and outputs 30fps interlaced, while 
a progressive player ignores the pulldown and outputs 24fps 
progressive.  As I understand it, the issue is that when makemkv ripped 
the content to a new container, it discards the pulldown flag, but kept 
the wrong framerate.  Or it could be setting the proper framerate, but 
including the pulldown flag.  Either way, it's doing something bad that 
timecode based players simply ignore and behave properly, but frame 
accurate players such as MythTV cannot handle with.

That said, this is likely something that can be corrected by minor fixes 
to the file.  If you open the file up in mkvmerge, what does it report 
the video's framerate as?

More information about the mythtv-users mailing list