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GPSYCHO - A LGPL'd Psycho-Acoustic Model

GPSYCHO is an open source psycho-acoustic and noise shaping model for ISO based MP3 encoders. GPSYCHO fixes some substantial bugs in the ISO demonstration source psycho-acoustic model (ISO psy-model). In addition, GPSYCHO adds mid/side stereo, real bit reservoir control, much improved critical band bit allocation routines, variable bit rate (optional) and very good pre-echo control. At 128kbs, the quality is significantly better than that produced by the ISO psy-model (as found in almost all other free encoders). An example of these improvements is shown in Screenshots. GPSYCHO is close to the quality of the FhG encoder, but there is still room for improvement. Read on if you want to help!

As this code is released under the LGPL, it can be used in any projects, even commercial ones. I would also encourage others to help improve GPSYCHO. Some things that would help:

The GPSYCHO algorithms are rigorously tested through listening tests. You can find more infomation here.

GPSYCHO operates in a number of modes. Notes are available to provide information about each of them:

New Features (which may need some tuning):

Features to try out:

Things we've learned from analyzing FhG (mp3enc3.1) produced .mp3 frames: