Compression Rates
In order to help calculate the size of media hard drives you will need for your system we have drawn up a simple table below which allows you to choose the quality you need to achieve, then easily see the number of minutes of storage you will get per GigaByte, as well as length of video you can expect on a typical 18 GB Hard Disk Drive filled to 90% of its capacity.
As a general 'rule of thumb': When working out how much storage you need it's a good idea to calculate the total duration of the projects you anticipate having on the system at any given time and then at least double or treble this figure - If you produce highly composited programmes you will need even more storage - This is because you need storage space for all the captured footage that you do not use, or that you trim out of your project; plus additional space for rendered effects and temporary files.
|
Digital or Equivalent Tape Format |
Capture Rate (MB/s) |
Compression Ratio |
Capacity in Min / GB |
|
|
|
VHS or |
1.0 |
20:1 |
17.1 |
4.5 Hrs |
18.5 Hrs |
|
DV Native or HDV @25Mb/s |
4.0 |
5:1 |
4.3 |
70 min |
4.85 Hrs |
|
MPEG-2 @ 50Mb/s |
6.0 |
3.3:1 |
2.8 |
45 min |
3.1 Hrs |
|
Digital Betacam |
8.0 |
2.5:1 |
2.1 |
34 min |
2.36 Hrs |
|
D:1 |
19.78 |
1.0:1 |
0.9 |
14 min |
58.3 min |
|
HD |
95 |
1.0:1 |
0.1875 |
2.91 min |
12 min |
