dmG728Decode(3dm)                                            dmG728Decode(3dm)



NAME
     dmG728Decode - implements the ITU (International Telecommunication Union)
     Recommendation G.728 decompression (LD-CELP).


SYNOPSIS
     #include <dmedia/dmaudioutil.h>

     DMstatus dmG728Decode(DMG728decoder handle,
                          unsigned char *ibuf, short *obuf, int nsamples)


PARAMETER
     handle    DMG728decoder structure, created by dmG728DecoderCreate(3dm),
               specifies the signal processing parameters.


     ibuf      pointer to input compressed data buffer. The data format is
               unsigned char (8-bit).  This bitstrem buffer must consist of a
               multiple of 10 bytes.


     obuf      pointer to output sample data buffer.  The data format is short
               (16-bit).  The samples are assumed to be two's complement.  The
               sampling rate must be 8 kHz.


     nsamples  number of sample in the output buffer to be generated. the
               value of nsamples passed to the G.728 decode/decode routines
               must always be a multiple of 40.


RETURNED VALUE
     Returns DMFAILURE or DMSUCCESS.


DESCRIPTION
     dmG728Decode(3dm) implements the ITU Recommendation G.728 decompression.
     The uncompressed data sampling rate is 8000 Hz.  And the compressed
     bitrate is 16000 bits/s. The mode for decoding operation can be


     DMG728POSTFILTERINGYES
     DMG728POSTFILTERINGNO


     that selects a decoder with or without postfiltering.  for speech/voice
     signal, postfiltering should be used.  For DTMF tone or music audio, no
     postfiltering should be used.  The mode is set by a call to
     dmG728DecoderSetParams(3dm). Without calling dmG728DecoderSetParams(3dm),
     decoder sets default to DMG728POSTFILTERINGYES.




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dmG728Decode(3dm)                                            dmG728Decode(3dm)



     see DESCRIPTION in dmG728Encode(3dm) for the discussion of decompression
     of a part of compressed bit stream beginning in the middle of a
     compressed data file.


NOTE
     G.728 algorithm was developed for sampling rate of 8 kHz.


SEE ALSO
     dmG728DecoderCreate(3dm), dmG728DecoderDestroy(3dm), dmG728Encode(3dm),
     ITU Recommendations G.728.











































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