--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pcmu2efr/gen160.c	Tue Apr 16 23:30:49 2024 +0000
@@ -0,0 +1,41 @@
+/*
+ * The code in this module generates 160 versions of linearized seqsyncu,
+ * shifted by one sample each, intended for feeding to EFR and AMR encoders.
+ */
+
+#include <stdint.h>
+
+extern const uint8_t seqsyncu_last_frame[160];
+extern const uint16_t pcmu_decode_table[256];
+
+uint16_t linear_inputs[160][160];
+
+static void
+gen_first_seq(void)
+{
+	unsigned n;
+
+	for (n = 0; n < 160; n++)
+		linear_inputs[0][n] = pcmu_decode_table[seqsyncu_last_frame[n]];
+}
+
+static void
+gen_sequence_m(unsigned m)
+{
+	unsigned n, s;
+
+	for (n = 0; n < m; n++)
+		linear_inputs[m][n] = 0x0008;
+	for (s = 0; n < 160; n++, s++)
+		linear_inputs[m][n] = linear_inputs[0][s];
+}
+
+void
+generate_linear_inputs(void)
+{
+	unsigned m;
+
+	gen_first_seq();
+	for (m = 1; m < 160; m++)
+		gen_sequence_m(m);
+}