Hi, how do you know when you have a transcoded audio file? (an mp3 in this case), besides bad sound quality how can you identify transcodes?, I have doubts about some downloaded music that appear to be 320kbps but they doesn't sound very well, I have EncSpot and Mr QuestionMan but on none of them I can't find traces of a transcode (or I don't know how to do it), actually I did a test myself with a Xing's 128kbps mp3 that I transcoded it to 320kbps using Foobar2000 & LAME and on both EncSpot and Mr QuestionMan it appears to be an "original" LAME 320kbps encode, how can I know when it's a transcode?...

Thanks!

1. check the frequency spectrum in a wav-editor. True 320kbps encoding is likely to have a high lowpass about 19-20KHz. Transcoding from lower bitrate is likely to have lower lowpass e.g. about 16kHz for 128kbps.

EDIT:
1b. If you have LAME 320kbps encoded with the "accurate length" option - you can check this in foobar. If Foobar will show "accurate length = YES" but NOT "mod 588 = 0" - then it is likely a transcoded mp3.

2. If you are relly desperate, then there is also another approach which you could try, but there is no tool yet which could do it automatically. You'll have to do it manually: (shameless plug!)

searching...
http://www.hydrogenaudio.org/forums/index....++source++lossy
http://www.hydrogenaudio.org/forums/index....++source++lossy