Table 1.

Comparison between [25], [17], [26], [5], [9] and the Proposed Method (inspired by [26]).

Parameters	Method of [25]	Method of [17]	Method of [26]	Method of [5]	Method of [9]	Proposed Method
Original Medium	Image	Image	Audio	Audio	Audio	Audio
Interpolation method	Neighbor mean interpolation (NMI)	$\begin{array}{c}{C}^{\prime }=C^T\times F_x\hfill \\ \times F_y\hfill \end{array}$	NDDI (taken from [34])	None	None	Linear (see (1))
Size of payload	Dynamic	Static	Dynamic	Static	Static	Dynamic
	Ni = ⌊log2|dn|⌋		$N_i=2^{\lfloor lo{g}_2|d_n|\rfloor }$			(see (9))
	$d_n=\lfloor \overline{y_n}-y_{n-1}\rfloor$	–	$d_n=\lfloor \overline{y_n}-y_{n-1}\rfloor$			(see (4)-(8))
Embedding	${\overline{y_{ij}}}^{\prime }=y_{ij}+b$	$\begin{array}{c}{\overline{y_{ij}}}^{\prime }=y_j^T-y_{ij}^T\hfill \\ mod{2}^k+b_l^{\prime }\hfill \end{array}$	${\overline{y_n}}^{\prime }=\{\begin{array}{c}\overline{y_n}-b_i^{\prime },\hfill \\ \text{if }{y}_{n-1}>\overline{y_n}\hfill \\ \overline{y_n}+b_i^{\prime },\hfill \\ \text{ if }{y}_{n-1}<\overline{y_n}\hfill \\ \overline{y_n},\hfill \\ \text{if }{y}_{n-1}=\overline{y_n}\hfill \end{array}$	Improved RDE	$\begin{array}{c}{y}_i^{\prime }=y_i\hfill \\ e_i+b\hfill \end{array}$	(see (11))
Reducing	None	None	None	None	None	(see (10))
Smoothing	None	None	Embedding: $\begin{array}{c}{\overline{y_{i,n}}}^{″}=\frac{{\overline{y_{(i-1),n}}}^{″}}{2}+\hfill \\ \frac{{\overline{y_{(i-2),n}}}^{″}}{2}\hfill \end{array}$	None	None	(see (12), (13), (14), (16))
			Extraction: $\begin{array}{c}{\overline{y_{(i-1),n}}}^{″}=2\times {\overline{y_{i,n}}}^{″}-\hfill \\ {\overline{y_{(i-2),n}}}^{″}\hfill \end{array}$