initial commit

2023-07-07 10:07:53 +02:00
commit ad8c3fbe74
18 changed files with 3554 additions and 0 deletions
--- a/companding/mulaw.h
+++ b/companding/mulaw.h
@@ -0,0 +1,47 @@
+#pragma once
+#include <cstdint>
+
+namespace trnr::lib::companding {
+// mulaw companding based on code by Emilie Gillet / Mutable Instruments
+class mulaw {
+public:
+    int8_t encode_samples(int16_t pcm_val) {
+        int16_t mask;
+        int16_t seg;
+        uint8_t uval;
+        pcm_val = pcm_val >> 2;
+        if (pcm_val < 0) {
+            pcm_val = -pcm_val;
+            mask = 0x7f;
+        } else {
+            mask = 0xff;
+        }
+        if (pcm_val > 8159) pcm_val = 8159;
+        pcm_val += (0x84 >> 2);
+        
+        if (pcm_val <= 0x3f) seg = 0;
+        else if (pcm_val <= 0x7f) seg = 1;
+        else if (pcm_val <= 0xff) seg = 2;
+        else if (pcm_val <= 0x1ff) seg = 3;
+        else if (pcm_val <= 0x3ff) seg = 4;
+        else if (pcm_val <= 0x7ff) seg = 5;
+        else if (pcm_val <= 0xfff) seg = 6;
+        else if (pcm_val <= 0x1fff) seg = 7;
+        else seg = 8;
+        if (seg >= 8)
+            return static_cast<uint8_t>(0x7f ^ mask);
+        else {
+            uval = static_cast<uint8_t>((seg << 4) | ((pcm_val >> (seg + 1)) & 0x0f));
+            return (uval ^ mask);
+        }
+    }
+
+    int16_t decode_samples(uint8_t u_val) {
+        int16_t t;
+        u_val = ~u_val;
+        t = ((u_val & 0xf) << 3) + 0x84;
+        t <<= ((unsigned)u_val & 0x70) >> 4;
+        return ((u_val & 0x80) ? (0x84 - t) : (t - 0x84));
+    }
+};
+}