what codec supports 24bit encoding ?

[FrEEwilL]

is there a codec/encoder that can compress 24 bits wave without converting to 16 bits ? (excluding lossless format)
lame and vorbis seems treat input as 16 bits even without verifying. and also how about 96/192khz ?

[Tes]

MPC, DTS, and maybe AAC ... not sure about AAC

But you could always convert the 24-bit WAV to 16-bit using SSRC as you are going to use lossy compression anyway. SSRC applies a dither algorithm so you should not loose much quality.

If you use MPC be aware that the codec is currently only tuned for 44.1 and 48kHz sample rates; again SSRC will be able to help with this.

[edit] added note about dither

[Gabriel_Bouvigne]

Lame treat input as floating. So if you have 24bits input, use it, Lame won't convert it to 16 bits.

[Sven Bent]

ogg.vorbsi supports up to 32bit float as input

Psytel AAC encoder support 24bit but have som size limitations (the encoder. NOT the codec)