[mythtv-users] Using USB to change channels on cable box?

Bruce Markey bjm at lvcm.com
Fri Aug 24 20:25:49 UTC 2007

Daniel Kristjansson wrote:
> On Wed, 2007-08-15 at 10:27 -0700, Bruce Markey wrote:
>> There is also the possibility of firewire capture but I haven't
>> gotten this to work yet and it would raise issues that are
>> supposed to be addressed by input groups. However, this opens
>> the possibility of capturing MPEG files directly from another
>> virtual 'capture card' with no physical tuner card.

The Saturday after writing this, I took another crack at firewire
capture and got it to work this time. It's a little quirky but
I'm now at a point of grabbing sample shows and addressing related
issues. I'm not quite to a point to rely on it for must see favorite

I'd like to update my recommendation to anyone with a standard
def TV and standard cable box to exchange your box for an HD
model. This was my best free upgrade ever. In addition to a
reliable channel changer and content from HD channels downscaled
to NTSC, I now get HDTV files over firewire. Even on a std def TV,
the color, contrast and accuracy are much better than analog
broadcasts and you can see the full resolution HDTV on a computer
monitor. I just wanted a more reliable channel changer and it's
been one pleasant surprise after another.

> I don't have a firewire STB anymore but I've been told that the
> input groups in the multirec branch does work as intended, allowing
> you to record some channels via firewire and others via the S-Video
> while having MythTV resolve conflicts properly.

I'd been planning to do so but my production tree has a mess
of patches right now. However this is a good excuse to test
the multirec branch. I also need the deinterlacer configuration
from the mythtv-vid branch.

> When I did have a firewire STB with CableVision most HD channels HD
> cable were available unencrypted over firewire even though only the
> broadcast channels were in the clear to a QAM tuner. On the other hand,
> RCN sent all their basic cable, including basic cable HD, in the clear
> for QAM, but encrypted all channels coming from their firewire STB
> including all broadcast channels. i.e. YMMV.

All of my digital cable channels are available over firewire
but this isn't a big step up and not worth using this method
I don't believe. I get 14 HD channels. As would be expected,
HBO, CineMAX and Showtime are not available over firewire but
the other 11 work perfectly.

I hacked a video source for these channels that I associate
with the firewire input. The plan is to prefer this input when
a show is flagged as HDTV and shown on one of these 11 channels.
However, for now I single record with a preferred input when I
want to try recording something.

--  bjm

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