Why is there 2 different resampling processes

[Ahkhune]

Hi,

I am currently reading the VLC source code and I am actually wondering why there is two different resampling processes concerning the synchronization issue of the audio. The is one resampling process at the input side and one at the output side.
Right now, I assume that the one at the input side gives a new streaming rate of the audio ES, and the one at the output side just relabel the packets that are contained in the buffer.

Please correct me if I am wrong.

Thanks

Ahkhune