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.

/*
 * Here we implement our binfile_read_frame() function.
 */

#include <stdio.h>
#include <stdint.h>
#include "binreader.h"

int binfile_read_frame(FILE *binf, uint8_t *frame)
{
	int cc, morelen;

	cc = fread(frame, 1, 1, binf);
	if (cc != 1)
		return 0;
	if (frame[0] == 0xBF)
		morelen = 1;
	else if ((frame[0] & 0xF0) == 0xC0)
		morelen = 30;
	else if ((frame[0] & 0xF0) == 0xD0)
		morelen = 32;
	else
		return -1;
	cc = fread(frame+1, 1, morelen, binf);
	if (cc == morelen)
		return 1;
	else
		return -2;
}