[mythtv-users] Few seconds missing in recordings

jeetu.golani at gmail.com jeetu.golani at gmail.com
Mon Oct 3 05:50:09 UTC 2011

Hi Alan,

Thanks for writing back :)....truly appreciate your help :)

I went through the example link you have given and the script it has :

lc="`cat /dev/last_dtv`"
if [ "$lc" -ne "$*" ]; then
/usr/local/bin/change-channel-dtv.bin $*
echo $* >/dev/last_dtv

I don't know what the change-channel-dtv.bin script is. In other
similar posts on external channel tuning I saw they were calling out
to an external tuner using irsend or something similar. In my case
since there is no external tuner irsend and other commands don't apply
the way I see it (pls correct me if I am wrong).

I ran a simple test wherein I put the above script and named it itself
as /usr/local/bin/change-channel-dtv.bin, created the /dev/last_dtv
and configured mythtv-setup to use this as the external command to
tune channels.

What does strike me as odd about this script is that there doesn't
seem to be an mechanism (like a return value) that tells mythtv that
the channel change succeeded or failed or is complete.

I then went ahead and also deleted all other channels barring from one
channel in mythtv. Just to make test simpler.

Therefore if there was some way for mythtv to call this script and
this script immediately returns then hopefully there wouldn't be the
few seconds loss in recording.

Unfortunately the recording still had the same 3 seconds loss :(

One scenario could be that it is still resorting to an internal
channel change refresh even though I have mentioned an external
command to change channels and maybe I have not set this up
correctly.....the other is as I mentioned above that the channel
change script needs to return something for mythtv to know change was
successful......or of course I have totally misunderstood all of this
and bungled it up ;)...any clues?

Truly appreciate your help :)

Bye for now

On Sun, Oct 2, 2011 at 10:43 PM, Alan Young <ayoung at teleport.com> wrote:
> jeetu.golani at gmail.com wrote:
>> Hi guys,
>> I'm using a PVR-150 to record programs using MythTV 0.24 over my
>> analog cable connection and have noticed that all my recordings have a
>> missing 3-5 seconds. Moreover this isn't constant and varies usually
>> in this range.
>> Playing with the settings to record past end of show by 5 seconds
>> works except when there's a back to back recording scheduled.
>> >From what I've read this seems to be time lost during tuning the
>> channel....is there a way to avoid this especially when you have to
>> back to back programs on the same channel lined up?
>> Any help would be truly appreciated :)
>> Bye for now
> You have to handle it in your channel change script.   See
> http://www.mythtv.org/pipermail/mythtv-users/2010-January/278875.html
> for an example.
> Alan
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