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.

/*
 * This header file contains some common definitions that have been
 * factored out of dtx_enc.h; the original code used the construct of
 * dtx_dec.h including dtx_enc.h, but in the opinion of this developer
 * it is better to factor out the common bits.
 */

#ifndef dtx_common_h
#define dtx_common_h
 
/*
********************************************************************************
*                         LOCAL VARIABLES AND TABLES
********************************************************************************
*/
#define DTX_HIST_SIZE 8
#define DTX_ELAPSED_FRAMES_THRESH (24 + 7 -1)
#define DTX_HANG_CONST 7             /* yields eight frames of SP HANGOVER  */

#endif