[mythtv] dvbsections.cpp / dvbchannel.cpp Changes In Progress

Ed Wildgoose lists at wildgooses.com
Thu Aug 26 02:23:13 EDT 2004

>Right now the PMT tables seem to come in about a second at worst after the Transport is tuned,
>which might be as fast as the recorder can start.  Then again it seems to take me a good second
>between channel changes right now in LiveTV, so slowing it down anymore would be even more

Please don't look to slow it down further.  I have a DVB-T card and it 
currently takes about 1 sec between channel changes, but liberal 
debugging statements show that only a small amount of that time is DVB 
related.  The rest of the time goes on pausing the ringbuffer, and audio 
code etc.  I have spent a while trying to track down why this is so, but 
I got lost in all the threads and couldn't follow the code path.  I 
think it might be partly to do with the size of the frontend tcp buffer 
and perhaps some code is waiting until the frontend is all played out 
before letting the backend "pause", but I'm not sure.

In any case VDR makes DVB-T channel changes in perhaps 100-200ms and so 
it's certainly possible to get down to this kind of level.  With DVB-T 
it takes noticably longer for the driver to tune if you leave any params 
on auto, so I fill in my database completely and this saves perhaps 
200ms tuning time! 

We also have channels which appear and disappear at certain times of the 
day here...

Thanks, looks like an interesting approach that you are using.  Have you 
studied the AutoPid patch to VDR for inspiration?

Ed W

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