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 C module provides some common tables for AMR parsing programs.
 */

#include "amr_defs.h"

char *amr_mode_names[16] = {
	"MR475",
	"MR515",            
	"MR59",
	"MR67",
	"MR74",
	"MR795",
	"MR102",
	"MR122",            
	"SID",
	"EFR-SID",
	"TDMA-SID",
	"PDC-SID",
	"InvalidC",
	"InvalidD",
	"InvalidE",
	"NO_DATA"
};

unsigned amr_bit_lengths[9] = {
	AMR_NBITS_475,
	AMR_NBITS_515,
	AMR_NBITS_59,
	AMR_NBITS_67,
	AMR_NBITS_74,
	AMR_NBITS_795,
	AMR_NBITS_102,
	AMR_NBITS_122,
	AMR_NBITS_SID
};