[mythtv-users] What hardware do I need to be able to dual record using Comcast cable?

[jedi]

On Thu, Oct 16, 2008 at 02:20:09PM -0400, Preston Crow wrote:
> > > Power used while encoding     = 50W/hr * 4hrs   = 200W
> > > Cost of power used to encode = .200kW * $0.09 = $0.018
> > > Space saved by encoding       = 5GB - 1.5GB     = 3.5GB
> > >
> > > Cost of space gained by encoding = $0.018/3.5GB = $0.005/GB
> > >
> > >
> > > Since the lowest price of new media is around $0.10/GB these days,
> > > transcoding (given this situation) appears to be an order of
> > magnitude
> > > cheaper still.
> 
> But if you watch the show, delete it, and re-record something in the
> same space, then do the transcoding again, the cost of the space is
> amortized over all the recordings that live in the same space, so with
> your cheap power, you have to churn through your disk 20 times until
> buying a larger disk is no more expensive than transcoding.  With my
> power costs, it's less than 10.
> 
> Taking that into account, it seems that it's cheaper for me to buy a
> larger disk than to transcode.

     ...except it's not just buying a single larger disk. It's buying 4.

     You can easily get 4x more effective space if you are willing to 
compromise on quality. This is close to the old rule of thumb for an
S1/S2 Tivo. That number jumps even higher for stuff like old SD content
on OTA HD channels. The compression you can get off of old reruns on an
HD station is unreal.

     So, it's not just "replacing a drive". It's multiplying it by 4.
(or whatever multiplier represents your comfort zone)

> 
> Of course, this is an academic analysis.  A real analysis would be to
> compare the full cost and power of two different configurations that
> you're considering, since you can't expand the size of an existing drive
> by 1GB for $.10.  (If only...)