Fix the syntax in math.md
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+27
-52
@@ -75,14 +75,12 @@ $$
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For object $o$, data point $d$, core channel $c$, and parameter band $p$, the coded difference $\Delta_{o,d,c,p}$ reconstructs to
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$$
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Q_{o,d,c,0}
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=
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Q_{o,d,c,0}=
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\left(O_q+\Delta_{o,d,c,0}\right)\bmod N_q,
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$$
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$$
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Q_{o,d,c,p}
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=
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Q_{o,d,c,p}=
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\left(Q_{o,d,c,p-1}+\Delta_{o,d,c,p}\right)\bmod N_q,
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\qquad p>0.
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$$
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@@ -92,8 +90,7 @@ $$
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The dequantized matrix coefficient is
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$$
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D_{o,d,c,p}
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=
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D_{o,d,c,p}=
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\left(Q_{o,d,c,p}-\frac{N_q}{2}\right)
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\frac{820}{4096(1+q_i)}.
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$$
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@@ -105,8 +102,7 @@ The effective denominator is therefore 4096 in coarse mode and 8192 in fine mode
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If the clipgain field consists of integer $x$ and mantissa $y$, then
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$$
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G_{\mathrm{clip}}
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=
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G_{\mathrm{clip}}=
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1+\frac{y}{32}2^{x-4}.
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$$
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@@ -152,8 +148,7 @@ $$
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$$
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$$
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M_{o,c,b,t}
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=
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M_{o,c,b,t}=
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(1-\alpha_t)P_{o,c,b}
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+\alpha_tD_{o,c,p(b)}.
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$$
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@@ -181,8 +176,7 @@ $$
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Let $\mathcal A_b$ denote the 64-band analysis-QMF operator with polyphase history state. Then
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$$
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X_{c,b,t}
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=
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X_{c,b,t}=
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\mathcal A_b\!\left(
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\widetilde x_c[64t],\ldots,\widetilde x_c[64t+63];
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\mathbf s^{\mathrm A}_{c,t}
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@@ -210,8 +204,7 @@ $$
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Band 0 of each surround channel additionally passes through a 21-tap complex FIR:
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$$
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\widehat X_{c,0,t}
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=
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\widehat X_{c,0,t}=
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\sum_{k=0}^{20}h_kX_{c,0,t-k}.
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$$
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@@ -222,8 +215,7 @@ These delays and filter histories are decoder state and cannot be reset independ
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For each object $o$, subband $b$, and slot $t$, the object's frequency-domain value is a linear combination of the five core channels:
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$$
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Z_{o,b,t}
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=
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Z_{o,b,t}=
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\sum_{c=0}^{4}
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M_{o,c,b,t}\widehat X_{c,b,t}.
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$$
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@@ -248,8 +240,7 @@ $$
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Treat `zone` as 64 complex values and apply an unnormalized 64-point FFT:
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$$
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F_k
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=
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F_k=
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\sum_{n=0}^{63}
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\operatorname{zone}_n
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\exp\!\left(-j\frac{2\pi kn}{64}\right).
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@@ -260,8 +251,7 @@ $$
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Define the rotation coefficient
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$$
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r_k
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=
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r_k=
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\frac12\left(
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\sin\frac{\pi k}{128}
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+j\cos\frac{\pi k}{128}
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@@ -277,8 +267,7 @@ $$
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Let $\mathcal S$ denote polyphase synthesis with a 640-value synthesis window and cross-slot state:
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$$
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\mathbf y_{o,t}
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=
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\mathbf y_{o,t}=
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\mathcal S\!\left(
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\mathbf R_{o,t},W,\mathbf s^{\mathrm S}_{o,t}
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\right).
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@@ -287,8 +276,7 @@ $$
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Object output is
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$$
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y_o[64t+r]
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=
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y_o[64t+r]=
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\operatorname{clip}\!\left(
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16\,\mathbf y_{o,t}[r],-1,1
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\right)G_{\mathrm{clip}},
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@@ -301,8 +289,7 @@ where $r=0\ldots63$. Synthesis state must advance continuously by slot.
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LFE bypasses the object matrix and inverse QMF and uses a 1217-sample delay. After the input and output scale factors cancel:
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$$
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y_{\mathrm{LFE}}[n]
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=
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y_{\mathrm{LFE}}[n]=
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\operatorname{clip}\!\left(
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x_{\mathrm{LFE,core}}[n-1217],-1,1
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\right).
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@@ -313,8 +300,7 @@ $$
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The lateral and longitudinal grids use $N=62$; the height grid uses $N=15$. The quantizer is
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$$
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q_N(k)
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=
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q_N(k)=
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\min\!\left(
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32767,
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\left\lfloor\frac{32768k}{N}+\frac12\right\rfloor
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@@ -404,16 +390,14 @@ $$
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The two-dimensional point gain is
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$$
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\mathbf G_{\mathrm{2D}}(u,v)
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=
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\mathbf G_{\mathrm{2D}}(u,v)=
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\mathbf h(u)\odot\mathbf v(v).
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$$
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For 5.1-family layouts with one horizontal surround pair rather than separate side and rear pairs, the longitudinal coordinate is
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$$
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v_{\mathrm{floor}}
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=
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v_{\mathrm{floor}}=
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\operatorname{clamp}(2v,0,1).
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$$
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@@ -424,8 +408,7 @@ Other layouts use $v_{\mathrm{floor}}=v$.
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Three-dimensional layouts compute floor gain $\mathbf G_f$ and height gain $\mathbf G_h$ separately:
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$$
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\mathbf G_{\mathrm{point}}(u,v,w)
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=
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\mathbf G_{\mathrm{point}}(u,v,w)=
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\cos\left(\frac\pi2w\right)\mathbf G_f
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+
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\sin\left(\frac\pi2w\right)\mathbf G_h.
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@@ -450,8 +433,7 @@ $$
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Maximum position compensation is
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$$
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A_{\max}
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=
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A_{\max}=
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-\max\left(4.5-1.5H-3F,0\right)
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\quad\text{dB}.
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$$
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@@ -479,8 +461,7 @@ $$
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The object's target-gain vector is
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$$
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\mathbf G_{\mathrm{target}}
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=
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\mathbf G_{\mathrm{target}}=
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G_{\mathrm{object}}
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G_{\mathrm{pos}}
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\mathbf G_{\mathrm{point}}.
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@@ -491,8 +472,7 @@ $$
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The coded position of an OAMD update is
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$$
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s_{\mathrm{coded}}
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=
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s_{\mathrm{coded}}=
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s_{\mathrm{frame}}
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+s_{\mathrm{outer}}
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+s_{\mathrm{OAMD}}
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@@ -502,16 +482,15 @@ $$
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The theoretical update position on the decoder-output PCM timeline is
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$$
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s_{\mathrm{theoretical}}
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=s_{\mathrm{coded}}+d_{\mathrm{decoder}},
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s_{\mathrm{theoretical}}=
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s_{\mathrm{coded}}+d_{\mathrm{decoder}},
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\qquad d_{\mathrm{decoder}}=1473.
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$$
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The speaker renderer retains the existing processing-block length $B=32$, so the aligned update point is
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$$
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\widehat s
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=
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\widehat s=
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B\left\lfloor
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\frac{s_{\mathrm{theoretical}}+B/2-1}{B}
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\right\rfloor.
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@@ -522,8 +501,7 @@ Thus, for frame-aligned updates, `align32(1473)=1472`. The 1473 value is the the
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For ramp duration $D$, the number of blocks is
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$$
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K
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=
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K=
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\left\lfloor
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\frac{D+B/2-1}{B}
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\right\rfloor.
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@@ -550,8 +528,7 @@ If no new metadata update intervenes, this is equivalent to a sample-wise linear
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For target output channel $c$:
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$$
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y_c[n]
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=
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y_c[n]=
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\delta_{c,\mathrm{LFE}}x_{\mathrm{LFE}}[n]
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+
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\sum_{o=1}^{15}x_o[n]g_{o,c}[n].
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@@ -560,8 +537,7 @@ $$
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Here
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$$
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\delta_{c,\mathrm{LFE}}
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=
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\delta_{c,\mathrm{LFE}}=
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\begin{cases}
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1, & c\text{ is the target layout's LFE channel},\\
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0, & \text{otherwise}.
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@@ -573,8 +549,7 @@ A layout without LFE output does not mix input LFE into other channels. After ob
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For PCM24 output, quantization is
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$$
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y_{24}[n]
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=
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y_{24}[n]=
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\operatorname{trunc}\left(
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8388607\,\operatorname{clip}(y[n],-1,1)
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\right).
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