[mythtv-users] LiveTV: stutter at program start/change resolved by short pause..?

Eloy Paris peloy at chapus.net
Fri Oct 1 16:14:52 UTC 2010


Hi Mark,

On Fri, Oct 01, 2010 at 11:20:38AM +0800, Mark Kendall wrote:

[...]

> 2. As per the OP, live tv will stutter on and off continuously until
> given some sort of a poke (usually a pause). I used to see this on my
> remote frontend, spent a large amount of time trying to debug it
> (without success) and finally fixed it by ensuring that the setting
> 'Always stream from the backend'(?) was enabled. That setting has been
> removed in trunk (and hence 0.24) and it is now the default. That
> said, I think whatever causes this problem is a pretty subtle issue
> and what worked for me probably won't work for everyone. I may just
> have changed some timing enough somewhere to avoid the problem. Given
> the amount of code that has changed since 0.23, it may also be fixed
> in trunk.

Wow, this setting has been removed? If I use the Myth protocol to play
my recordings I experience the problems that I described here:

http://www.gossamer-threads.com/lists/mythtv/users/452639

Accessing the recordings via NFS gives me very smooth playing and
instant rewind and fast forward.

It'll be a bummer for me if I can't play my recordings by accessing them
directly via NFS and if the performance problems I experience when using
the Myth protocol to access the recordings are still there in .24.

Do you know why the setting was removed?

----------------------------------------------------------------------
Sorry, I decided to look more into this after I originally wrote my
email. Here's what I found:

http://svn.mythtv.org/trac/changeset/26011 contains the change that
removes the setting. What the changeset does is to actually remove a
way for users to set, via the GUI, the variable "alwaysStream". But
alwaysStream is set to 0 by default. This means that a local file will
be tried first, and if that fails, we will fall back to using the Myth
protocol. That works for me ;-)
----------------------------------------------------------------------

> 3. Temporary picture break up/frame loss when the program changes
> (N.B. not a channel change). This is a symptom of how live tv is
> implemented as a series of recordings rather than as one single
> stream. When the frontend is watching livetv and comes to the end of
> the current 'recording', it will ask for the next recording and switch
> over to that. As currently implemented, this involves tearing down and
> recreating various items and in most situations this just doesn't
> happen fast enough to avoid some dropped frames. There may also be
> some unrecoverable frame loss happening in the backend itself as the
> recorder switches from one program to the next (i.e. the two recording
> files don't join seamlessly). Improving this is something I'd like to
> try and tackle for 0.25.

I see this one all the time, but since it is just a second or two and
only at show boundaries, it doesn't bother me at all.

Cheers,

Eloy Paris.-


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