MP3
(and other lossy codecs)
for reference:
the CBR birates (192, 320, etc) rank in numerical order
the common VBR bitrates are V2 (aka APS) and V0 (aka APX); the latter is of higher quality
with a bit of artistic license, you can think of them as being in this order:
-192, V2, 320, (V0) -- in terms of duping, and the V0 is a special case
once a release is represented on the site in lossy, new uploads must be:
of a higher bitrate
be a V0 encode, which is always allowed regardless of pre-existing lossy encodes
so you can see, that the earlier torrent takes precedence over new torrents, unless the new torrent matches the above criteria
some examples:
[*] the torrent: Hangar - The Reason of Your Conviction [2007/MP3/192] is uploaded.
because this is the lowest allowable bitrate, any of the following are valid uploads: V2, 320, V0
if the 320 is upped next, the V2 (as it is lower), no longer qualifies
if the V0 is upped next, neither the 320 nor the V2 may be uploaded
[*] the torrent: Hangar - The Reason of Your Conviction [2007/MP3/320]
if the highest bitrate is uploaded first, it locks out all lower bitrates, except V0
[*] when the 192 is upped first, and others are upped in ascending order as in our first example, further uploads are valid, and do not trump the lower ones. ie all torrents are left on the site.
[*] when the higher bitrates are upped first, further uploads of lower bitrates are deleted as dupes.