[mythtv-users] analog to digital setup

Raymond Wagner raymond at wagnerrp.com
Thu Dec 29 08:04:58 UTC 2011


On 12/29/2011 00:36, GMAIL wrote:
> Athlon II x4 3.0 GHz
> 8gb ram and 1.5 TB of disk split into multiple raid arrays for storage using mdadm

That seems rather odd.  To bother using RAID for a mere 1.5TB means 
you're using some fairly old drives, matched with some fairly new 
hardware.  1.5TB is only going to get you a couple hundred hours, 
independent drivers are much better than a striped array for recording, 
especially if you expect to have a lot of simultaneous recordings, and 
personally, I would just be losing faith in their reliability.  You 
should consider replacing them with larger independent drives in a few 
months when prices start dropping back off.

> 2x2250
> Comcast VT is my cable provider

The HVR-2250 is a basic QAM tuner, which means you're only going to be 
able to record unencrypted digital cable.  On Comcast, that's pretty 
much going to limit you to the local broadcast channels.  Consider 
picking up a cablecard tuner such as a DCR-2650 or HDHomeRun Prime.  
Those are both supported to some extent currently in 0.24.  
Alternatively, the InfiniTV will be supported in 0.25.  These will be 
able to record any encrypted channels marked as 'copy freely', which on 
Comcast means just about everything besides the premium channels (HBO, 
Showtime, etc...).

> 1) it is unclear how to set up the four tuners to record either analog or digital depending on the target channel - if that is even possible.

The analog and digital sides of the card show up as independent devices 
in Linux and MythTV.  Since the analog and digital sides are mutually 
exclusive, MythTV needs to be informed of such.  You set that by putting 
them in a shared input group.

> 2) it is also unclear how to target the digital Channels in the listings when they have analog matches as well e.g.: channel 3 analog is 3-1 hd

If you have a channel that is available in both analog and digital, 
never use the analog.  Remove the analog channel from your Schedules 
Direct lineup, and from your video source.  MythTV will then only know 
to record from the digital.

> some channels seem to only be offered over analog eg PBS.

Don't expect that to remain the case.   Most Comcast franchises have 
long since dropped their analog broadcasts, requiring their users to 
instead use mini-boxes.  Since the mini-boxes only have a single 
modulated output, and they channels they use are all encrypted, your new 
2250s would only be useful as a single analog input each.  You would 
need cable boxes with baseband outputs to be able to use both inputs, as 
well as digital, or you would need to keep your old 150 and 350.


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