[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).
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