If the quantization noise can be kept below the masking threshold, then the compression results should be indistinguishable from the original signal. Joint Stereo Joint stereo coding takes advantage of the fact that both channels of a stereo channel pair contain far the same information. These stereophonic irrelevancies and redundancies are exploited to reduce the total bitrate. Joint stereo is used in cases where only low bitrates are available but stereo signals are desired. Quantization and Coding A system of two nested iteration loops is the common solution for quantization and coding in a Layer-3 encoder.
Quantization is done via a power-law quantizer.
In this way, larger values are automatically coded with less accuracy and some noise shaping is already built into the quantization process. The quantized values are coded by Huffman coding. As a specific method for entropy coding, hufman coding is lossless. Thus is called noiseless coding because no noise is added to the audio signal. If the number of bits resulting from the coding operation exceeds the number of bits available to code a given block of data, this can be corrected by adjusting the global gain to result in a larger quantization step size, leading to smaller quantized values.