[mythtv-users] HD Homerun Tuning Problems

[Daniel Kristjansson]

On Mon, 2007-06-11 at 06:07 -0400, William Munson wrote:
> Kirk Bocek wrote:
> > R. G. Newbury wrote:
> >   
> >> Scanning, as such, is NOT broken in mythtv. What generally is broken is 
> >> what cableco's send us: a stripped stream with no identifying data, on 
> > Why is Myth having a problem with *some* of the channels? And it can see 
> > *some* service numbers on one multiplex but not others.
> That is because it IS broken, despite what Geoff says. There are two 
> significant issues with the myth scanner as documented by recent tickets 
> in SVN.

Mr. Newbury is correct.

> 1. Transports with a stream labeled 0.0 will cause all streams to not be 
> added to the database.
> 2. Transports with both a HD and SD stream will cause all streams to not 
> be added to the database.

This is not an accurate description any of the existing
problems. Transports without channel numbers are added by
MythTV's channel scanner. Transports with both HD and SD
streams are added to the database as well.

There is a problem with adding channels to the database when
a transport contains both channels with channel numbers and
unnamed channels. MythTV assumes that these unnamed channels
are just testing channels that it shouldn't be interested in.
However there are some cable companies in the USA that mix
channels with and without channel numbers on the same multiplex,
presumably because they are required by law to have channel
numbers for OTA channels but the FCC does not require this
for other channels. I think this is what you are remembering
as problems #1 & #2, and in this case R. G. Newbury is entirely
correct, this is a cable company problem which we need to work
around. They are sending the channel number info in a separate
stream for some of the channels, this is not QAM-256, QAM-64,
or 8-VSB modulated so the HDHomeRun can not see the data.
You can see we already have some workarounds for this because
when a transport contains only unnamed channels we add them
to the database, we just didn't account for cable companies
with 'half-broken' transports.

> There is supposed to be work being done to correct these and other 
> problems with the channel scanner however nothing has come out of the 
> branch in several weeks. Perhaps the dev is finding it harder than 
> expected or maybe it requires a complete re-write of the code. I just 
> hope its fixed soon.

I haven't been working on it at all in the last few weeks.
What time I have for MythTV I've been spending on the DVB
recorder and video playback. I'm hoping to have some time
for channel scanning after the next MythTV release. (Aside
from fixing some regressions in SVN head before the release).

-- Daniel