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 holds some common data items for IETF RFC 4867
 * AMR file format.
 */

#include <stdint.h>
#include "amr_defs.h"

const char amr_file_hdr[IETF_HDR_LEN] = "#!AMR\n";

const uint8_t extra_bytes_per_ft[9] = {12, 13, 15, 17, 19, 20, 26, 31, 5};