Re: compression ratio
Hi,
Compression ratio means the amount of compression in order to coding a raw data, in other words when we say the compression ratio is 25:1 it means that the size of coded stream is 1/25 of the original one, in such case you can convert a 100kB file to a 4KB one,
About the DCT, because DCT coefficients are fractional and not integer, so there is loss when we do inverse DCT, but I thinks the amount of loss is negligible.
Best regards,
Mehdi