Using shoutcast v2 and SHOUTcast Transcoder 2 as autodj source we have low quality when stream live to shoutcast v1 dj port of sctransv2 using an aacp live encoder. We better the quality streaming at high bitrates in MP3 format.

So the question is:

1 - have someway to broadcast via sc_transv2 dj port at lowert aacp bitrates? Or always the sc_transv v2 will re encode the live broadcast? Have some config to permit a live encoder connect and broadcast via sc_transv2 dj port with the original quality of the live encoder?

it will always re-encode the audio even if it's already in the correct format. there is nothing you can do to change that behaviour and it won't be changed officially as sc_trans is dead.

I believe it was DrO who said somewhere that you might get better results if you increase the bitrate of the live stream. (i.e: if your stream is 128kbps then set your live encoder to broadcast at 192kbps - sc_trans will still re-encode it to 128kbps, but since it will receive a better audio to work with, at 192kbps, it might sound better after re-encoding it at 128kbps)

yup, if the input stream is a higher bitrate than the re-encoding the transcoder does will lessen the impact of the double-encoding which is done (from the DJ/relay and then what sc_trans does).

it makes sense why sc_trans does that based on how it was implemented, but obviously from an audio quality view point, it was a very bad decision.