View Full Version : What bitrate


David Barnes
September 30th, 2009, 11:29 AM
Hi
According to Canon the top bitrate is 330MB/MIN. Using plain maths I make it that top rate is 330MB/60SEC=5.5MB/SEC. How does this compare with Mimi DV 24Mb/SEC or HDV 25MB/sec.
AM I WRONG?????
DAVID

Michael Murie
September 30th, 2009, 11:42 AM
I always get confused with Mbits; I work better with X min = Y GB.

Given that 12 minutes of video equals approx 4GB of video, then 1 hour of video is about 20GB. But one hour of DV or HDV is approx 13GB. So from those calculations, the transfer rate of the 7D must be almost twice as fast as that of DV/HDV

I think ;)

David Barnes
September 30th, 2009, 01:48 PM
According to your suggestion i would calculate 330x60=19.8gig

Evan Donn
September 30th, 2009, 04:18 PM
Hi
According to Canon the top bitrate is 330MB/MIN. Using plain maths I make it that top rate is 330MB/60SEC=5.5MB/SEC. How does this compare with Mimi DV 24Mb/SEC or HDV 25MB/sec.
AM I WRONG?????

Wrong about what? You are mixing megabytes and megabits there, so maybe you are wrong...

5.5MB (megabytes)/second = 44Mb (megabits)/second

MiniDV and HDV are both 25Mb (megabits)/s, so roughly 3.2MB (megabytes)/s

So the proper comparison is:

7D at 5.5MB/s vs. DV/HDV at 3.2MB/s
or
7D 44MB/s vs. DV/HDV at 25Mb/s

So whichever way you look at it the 7D runs over 70% more data per second than DV/HDV. It also uses a newer, more efficient codec, although that doesn't necessarily mean much because there is a lot of variation in real time hardware encoding performance.

David Barnes
October 2nd, 2009, 01:31 PM
EVan thanks for clearing up the confusion. The quality looked too good for 5mb/s now I know why.

Brian Parker
October 4th, 2009, 08:41 PM
I looked at the bitrate graph on a file in Premiere and it seems that it is variable bitrate. A good portion of the video I took was floating around 3.5MB/s