Hello everybody, ok can you help me, i need to be able to identify audio that has been transcoded from a lower to a higher bitrate, and from one format to another, is this possible?? thanks.............

You can spot low to high bitrate conversions via spectral analysis, however its not a fullproof method. For example, if you have a high-bitrate audio file that shows a frequency cut at 14khz its most likely a transencode from a lower format - OR it is not a transencode, just compressed with a horrible horrible codec.

Usually you can hear it. At least if your ear is trained.

If you listen very easily annoying flanging effects (mainly in the cymbals or guitars) in 256 or 320 kbps mp3 files, as also in high VBR bitrate files (around 200 kbps); then, is very possible that these files are transcode from a low bitrate files.