[mythtv-users] I may have SOLVED the 5C cable encryption - DOH!

Michael T. Dean mtdean at thirdcontact.com
Thu May 10 20:26:56 UTC 2007

On 05/10/2007 03:54 PM, Chad wrote:
> On 5/9/07, Michael T. Dean <mtdean at thirdcontact.com> wrote:
>> On 05/09/2007 02:23 PM, Asher wrote:
>>> AFAIK DV is very large, it is what is used on digital camcorders.
>> IIRC, about 11GB/hr for NTSC at 720x480, but that's what transcoding is
>> for.  :)
> Capturing from my camcorder yields much more than that.  The DV files
> that dvgrab produces from the firewire port (that my camcorder is
> attached to) are about 2GB/min.  From a ~10 minute capture the file is
> ~25GB.

True DV video uses a fixed bitrate of 25.146Mb/sec and audio uses 
1.536Mb/sec.  This works out to a minimum of 11.2GiB/hr.  When you add 
in subcode data, error detection, and error correction (about 
8.7Mb/sec), you can go as high as 35.4Mb/sec (14.8GiB/hr).  But, the 
~11GB/hr is the smallest you'll go for a video and audio stream in DV 

DV50 doubles the bitrate of the video, and there are HD formats and 
other variants, too.  (HDV, ProHD and a bunch more about which I know 
absolutely nothing.)

So, your camera probably uses a different format (variant of DV) that it 
generically calls "DV".  If the device the OP mentioned does, too, then 
the video will take more room than the ~11GB/hr I quoted.  But, since, 
IMHO, 11GB/hr is /way/ too large for 720x480 video, that only supports 
Asher's and my assertion that DV video would be huge.

This page has a pretty good comparison of sizes of various formats.  


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