FreeCalypso > hg > gsm-codec-lib
view libtwamr/d_gain_c.h @ 477:4c9222d95647
libtwamr encoder: always emit frame->mode = mode;
In the original implementation of amr_encode_frame(), the 'mode' member
of the output struct was set to 0xFF if the output frame type is TX_NO_DATA.
This design was made to mimic the mode field (16-bit word) being set to
0xFFFF (or -1) in 3GPP test sequence format - but nothing actually depends
on this struct member being set in any way, and amr_frame_to_tseq()
generates the needed 0xFFFF on its own, based on frame->type being equal
to TX_NO_DATA.
It is simpler and more efficient to always set frame->mode to the actual
encoding mode in amr_encode_frame(), and this new behavior has already
been documented in doc/AMR-library-API description in anticipation of
the present change.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Sat, 18 May 2024 22:30:42 +0000 |
| parents | a723d9f9f697 |
| children |
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/* ******************************************************************************** * * GSM AMR-NB speech codec R98 Version 7.6.0 December 12, 2001 * R99 Version 3.3.0 * REL-4 Version 4.1.0 * ******************************************************************************** * * File : d_gain_c.h * Purpose : Decode the fixed codebook gain using the received index. * ******************************************************************************** */ #ifndef d_gain_c_h #define d_gain_c_h "$Id $" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "tw_amr.h" #include "typedef.h" #include "gc_pred.h" /* ******************************************************************************** * DECLARATION OF PROTOTYPES ******************************************************************************** */ /* ************************************************************************** * * Function : d_gain_code * Purpose : Decode the fixed codebook gain using the received index. * Description : The received index gives the gain correction factor * gamma. The quantized gain is given by g_q = g0 * gamma * where g0 is the predicted gain. To find g0, 4th order * MA prediction is applied to the mean-removed innovation * energy in dB. * Returns : void * ************************************************************************** */ void d_gain_code ( gc_predState *pred_state, /* i/o : MA predictor state */ enum Mode mode, /* i : AMR mode */ Word16 index, /* i : received quantization index */ Word16 code[], /* i : innovation codevector */ Word16 *gain_code /* o : decoded innovation gain */ ); #endif