dmG728Decode(3dm)dmG728Decode(3dm)NAMEdmG728Decode - implements the ITU (International Telecommunication Union)
Recommendation G.728 decompression (LD-CELP).
SYNOPSIS
#include <dmedia/dm_audioutil.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 DM_FAILURE or DM_SUCCESS.
DESCRIPTIONdmG728Decode(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
DM_G728_POSTFILTERING_YES
DM_G728_POSTFILTERING_NO
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 DM_G728_POSTFILTERING_YES.
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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 ALSOdmG728DecoderCreate(3dm), dmG728DecoderDestroy(3dm), dmG728Encode(3dm),
ITU Recommendations G.728.
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