Generation loss

Well known from the analog world, make a copy of a copy of copy and with each pass you lose some quality.

In the digital world you don’t have this problem.
Each copy is bit identical to the master.

 

If you apply lossy compression and use this as a source for anoter lossy compression, you do get an accumulation of the artifacts.
In this case you do loose quality.

Berndhold [1] demonstrates this by encoding/decoding audio using various lossy compression codecs.
He used 100 passes.

It demonstrates the generation loss and the difference in performance of various encoders nicely.

Between the usual rigid complains at Hydrogen [2] about the violation of the TOS, there are some remarks that do make sense about the method used.

1. Nine different audio encoders 100-pass recompression test - Bernhold's random tech tips
2. Nine different codecs 100-pass recompression test - Hydrogenaudio