AN3143

ADPCM codec

Doc ID 17011 Rev 1

5/13

1.4

IMA ADPCM compression

The IMA ADPCM compression algorithm encoder calculates a difference (d) between a 16-

step is the same one as that used by the decoder. Figure 2 provides a flowchart of the

ADPCM encoder. It also shows the decoder building blocks with the functionality described

in Section 1.3 (see filled light green components). As the encoder covers identical blocks to

the decoder and produces identical results, there is no need to store prediction information.

The quantized difference is the only core information about the coded samples which needs

to be stored or transmitted.

Figure 2.

ADPCM encoder

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