F4V or FLV file sizes when saved during streaming.

Report · Sep 24, 2012

Hi,

The is probably a daft question but I'll ask it anyway.

I ran some tests recently as we are looking at saving the streams that go the FMS 4.5. We normally stream inhouse at 1500 kbps, so I wanted to see what kind of storage I would need if we were going to save the streams.

I did a test @ 1500 kbps, 720 x 480 using h.264 and saved as an f4v file.

I limited the duration to 1 minute to see what 1 minute of saved video would be.

It turned out to be 10. MB's which surpised me, I expected it to be higher, as the quality was very high.

I know megabytes and Megabits are different, but I still expected a higher file size.

I calculated that at 1548 kbps * 60s = 92881 (+ 48 kbps Audio )

92881 \ 1024 = 90.7 MB

The file size was actually 10.2 MB.

Is there a calculation I can use to work out the correct file size so that I can determine the Hard Drive sizes I need, or is it guesswork based on the H.264 codec?

Report · Sep 25, 2012

I may be lining myself up for a kicking here, however I believe that kbps is kilobits per second (8 bits to a byte) and kBps is kilobytes per second. Therefore:

vided @1500kbps for 60 seconds = 90,000 kb

audio @ 48kbps for 60 seconds = 2,880 kb

total kilobits (kb) = 92,880

Convert to kilobyte (kB): 92880 / 8 = 11,610 kB

Conver to megabytes: 11,610 / 1024: 11.3Mb

Therefore 10.2Mb seems okay to me...