[mythtv] Channel change time

[Devin Heitmueller]

On Sun, Jun 6, 2010 at 7:21 AM, James Courtier-Dutton
<james.dutton at gmail.com> wrote:
> I have found out where the 2 second delay is.
>    MPEGStreamData *streamData = NULL;
>    if (HasFlags(kFlagWaitingForSignal) && !(streamData =
> TuningSignalCheck())) {
>        return;
>    }
>
> So maybe this long channel change time is caused by the
> "TuningSignalCheck()" function call.
> I would have thought that this function should be quick to return, so
> I will look into it further.

I cannot speak to MythTV's specific implementation, but bear in mind
that the linux-dvb API has  model such that the tuning ioctl() is
designed to return immediately, and then the application is expected
to poll for the lock state.

So when you said 700ms, were you looking at the time for the tuning
ioctl()?  If so, then you didn't have a lock at that point and the
code above was polling until a lock was achieved.

Devin

-- 
Devin J. Heitmueller
http://www.devinheitmueller.com
AIM: devinheitmueller