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External versus internal DVR storage capacity

Why is internal DVR drive compressed more than external DVR drive stored data? Eight one hour programs stored by DVR onto external 500GB drive occupies 44 percent of capacity. Forty-one one hour programs occupies 80 percent of the DVR's internal 500GB drive capacity. Grossly simplified and stated, that equals almost 27 plus GB of data per one hour of program on the external drive versus roughly 9.75 GB of capacity on the internal 500GB drive. Why does the internal DVR drive use less storage capacity than the DVR's external drive?

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armond_in_nj1

@LHJR wrote:

Why is internal DVR drive compressed more than external DVR drive stored data? Eight one hour programs stored by DVR onto external 500GB drive occupies 44 percent of capacity. Forty-one one hour programs occupies 80 percent of the DVR's internal 500GB drive capacity. Grossly simplified and stated, that equals almost 27 plus GB of data per one hour of program on the external drive versus roughly 9.75 GB of capacity on the internal 500GB drive. Why does the internal DVR drive use less storage capacity than the DVR's external drive?

Not sure how your data was derived, but have you taken into account SD recordings versus HD recordings? I have both internal and external storage for the DVR, and the capacities of both dev ices parallel the nominal storage specifications almost exactly (based on actual recording experience).

gs0b

Be sure you are comparing programs with the same video quality. SD takes way less space than HD. If you haven't accounted for SD vs. HD, that makes your numbers meaningless.

The internal hard disk is used for more than DVR storage. The disk also holds the real-time playback buffer which stores up to two hours of the current program (in HD), the operating system, configuration information, maybe a VOD buffer and probably some other data . The percent used number represents is based on the space allocated for the DVR function, not the entire disk.

You may be able to figure out the DVR space by using the data on amount of space used by HD and SD programs on both the internal and external drives. The external drive probably has some overhead space that isn't used for DVR, however I'm guessing it is much smaller than the internal drive.

Happy Recording!

LHJR

Thanks for both replies so far! I have recorded all programs as HD and simply divided the percentage of capacity used by the number of similar length programs stored. I hadn't considered the overhead variable as I just looked at both as 500GB SATA drives (480GB actual storage available). I have also found posts about the (AV) rating of a disk drive versus routine data storage rating. I must learn more about that to get a precise comparison of disk space available for data versus AV data storage. I have looked at the AV storage of HD over-the-air recordings on my PC using Windows Media Center, but that too could be misleading because it's a different format than Verizon's DVR. Any enlightenment would be appreciated to help me better understand DVR internal versus external storage capacity would be great. Thanks!

0100010

Also do not discount MPEG4 vs MPEG2 HD recordings.

LHJR

Thanks for the input. It led me to this site; http://www.2mcctv.com/blog/2012_05_09-h-264-compression-dvr-mjpeg-mpeg4/ where I found H.264 uses much less HDD space than MPEG-4. Perhaps the Motorola QIP-7232-2 uses H.264 for its internal HDD, and uses MPEG-4 for external drive storage. The MPEG-4 supports the licensing I'm sure Verizon wants and a quality image capacity. However, the answer to the question of what formats does the Motorola QIP-7232-2 use to store video programming on its internal HDD and onto an external drive hasn't been anwered.

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