af_hdcd: hdcd_analyze_gen() using int instead of float

Signed-off-by: Burt P <pburt0@gmail.com>

libavfilter/af_hdcd.c

@@ -1318,11 +1318,10 @@ static void hdcd_analyze_prepare(hdcd_state *state, int32_t *samples, int count,
 /** encode a value in the given sample by adjusting the amplitude */
 static int32_t hdcd_analyze_gen(int32_t sample, unsigned int v, unsigned int maxv)
 {
-    float sflt = sample, vv = v;
-    vv /= maxv;
-    if (vv > 1.0) vv = 1.0;
-    sflt *= 1.0 + (vv * 18);
-    return (int32_t)sflt;
+    static const int r = 18, m = 1024;
+    int64_t s64 = sample;
+    v = m + (v * r * m / maxv);
+    return (int32_t)(s64 * v / m);
 }
 
 /** behaves like hdcd_envelope(), but encodes processing information in