[mythtv-users] Best Sat receiver for Dish Network

Michael T. Dean mtdean at thirdcontact.com
Thu Mar 9 07:40:00 UTC 2006


On 03/08/2006 05:38 PM, Michael T. Dean wrote:
> Actually, DirecTV will also output component analog or digital 
> DVI/HDMI, but it does us no good.
>
> Even if you cobbled together an array of BTTV capture cards (and 
> worked up a driver) to grab that analog output or created your own 
> DVI/HDMI capture mechanism, you'd be looking at some serious storage 
> requirements.  Uncompressed 16-bit color video at 720x480 (interlaced 
> at 30 frames/sec and 60 fields/sec) takes about 70GiB/hr and 105GiB/hr 
> for 24-bit color.  Since we can't encode it in real time, we'd have to 
> store the uncompressed, then let the CPU crunch for hours to encode 
> each hour captured.
>
> With ATSC, the storage requirements are much greater:
>
> Format     16-bit Color     24-bit Color
> ------     -----------      ------------
> 720p24     148 GiB/hr       222GiB/hr
> 720p30     185 GiB/hr       278GiB/hr
> 720p60     371 GiB/hr       556GiB/hr=9.3Gib/min
> 1080p24    334 GiB/hr       501GiB/hr
> 1080p30    417 GiB/hr       626GiB/hr=10.4GiB/min
> 1080i60 (same as 1080p30)
>
> And, on top of that, you'll need to store the audio (which you should 
> be able to compress in real-time ;).

Hmmm.  A very smart person has since told me that video typically uses 
12-bit color.  So it seems you would only need to store half the amount 
of data in the 24-bit column.  That means you could even fit an hour of 
HDTV on a single 400GB disk (320GB is just a little too small for 
1080i60/1080p30, but would work for 720p60).

Mike


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