1) The exact frequency values for the Oscillators are (22.5792Mhz/24.576Mhz) & (45.1584Mhz/49.152Mhz)
2) Both the versions supports at most of the mp3 files.
3) Only different between 45/49 version and 22/24 version is, in 22/24 version ,it supports upto 176.4K(44.1k family) and 192k(48k family) sampling rate audio files.But in case of 45/49 version supports above 176.4k(44.1k family) and 192k (48k family).
4) And both the versions ,it wouldn't degrade any audio quality.Because both the versions of Oscillators(from NDK) having very low jitter (3-5ps).
hope this helps ..