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.

/*-----------------------------------------------------*
 | Table for routine Inv_sqrt().                       |
 -----------------------------------------------------*/

static const Word16 table[49] =
{

    32767, 31790, 30894, 30070, 29309, 28602, 27945, 27330, 26755, 26214,
    25705, 25225, 24770, 24339, 23930, 23541, 23170, 22817, 22479, 22155,
    21845, 21548, 21263, 20988, 20724, 20470, 20225, 19988, 19760, 19539,
    19326, 19119, 18919, 18725, 18536, 18354, 18176, 18004, 17837, 17674,
    17515, 17361, 17211, 17064, 16921, 16782, 16646, 16514, 16384
};