How to find Compression Ratio?

[geewhan]

I want to know how to find compression ratio for

<IPPPPPPPPPPPPP>I (H263)

Assuming that the average compression ratio is Cr=15 for I frames
P frames is 40
B frames is 80


I know that compression ratio is

Cr = original/compressed

but how does that help if we have an average?

[jagabo]

The compression ratio is usually stated as the average for the entire video. Each I/P/B frame will have a different ratio. I don't know any program that will tell you the average of all I frames, all P frames, and all B frames, separately.

[geewhan]

So

I frame 1/15 =0.066667

P frame 1/40 =0.025

B frame 1/80 =0.0125

Is that what you mean by?

[jagabo]

I don't know what you're asking. There is not a fixed ratio between frame types.