How can this be?

Dan Sherman wrote on 6/20/2010, 2:02 PM

Medium shot minimal movement green screen project shot at 720p-30p HD (Panasonic HPX170).
Rendered to .MOV uncompressed as requested by client.
It is 6.21 GB!
How can that be as the MXF files from the camera are only about a 1GB per minute?
I just don't understand how one minute equals 6.21 GBs.
But then I'm no technician, far from it. Very far and falling further.
Anyone else share my surprise.
Trying again, rendering to PNG, slower going, by maybe file is smaller.

OH! And happy father's day to all yooz Vegasonian Dads!

Comments

PerroneFord wrote on 6/20/2010, 2:37 PM

Because an uncompressed stream is very large. At 1080p it's 1500Mb/s. I am not sure for the numbers for 720p, but I'd guess in the 800-1000Mb/s range. Your numbers are fine. Uncompressed makes huge files. Get used to it.

kkolbo wrote on 6/20/2010, 5:08 PM

We have become so accustom to the efficient compression that is being used that we have forgotten how much data raw video uncompressed contains. Your numbers sound about right.

musicvid10 wrote on 6/20/2010, 6:10 PM

Compare the rendered bitrates between uncompressed and MXF and you'll have your answer.

A. Grandt wrote on 6/20/2010, 10:36 PM

Or compare with h.264, if I recall that is one of the hardest compressions currently in use.

a 2.6 sec clip was 6MB at 14.7Mbps h.264, became 2.6GB uncompressed. That is a compression ratio of above 400:1.