Add the Normalization as a standalone script

The wt-tool normalization is useful for raw i16 .wav files also so
add it as a standalone scrpit (albeit with a bit of copy and paste)

scripts/wt-tool/normalize-i16-to-i15.py

@@ -0,0 +1,104 @@
+# Just the normalization path of the wave table code
+# A bit of copy and paste going on here from wt-tool. Should fix that one day
+
+from optparse import OptionParser
+import wave
+
+
+def main():
+    parser = OptionParser(usage="usage: % prog [options] infile outfile")
+    parser.add_option("-n", "--normalize", dest="normalize", default="half", metavar="MODE",
+                      help="""(Create only) how to normalize input.
+'half' input wav are divided by 2 (so 2^16 range becomes 2^15 range);
+'peak' input wav are scanned and re-peaked to 2^15.
+""")
+    (options, args) = parser.parse_args()
+    if(len(args) != 2):
+        print("Please specify an input file and output file\n")
+        parser.print_help()
+        return
+
+    inf = args[0]
+    outf = args[1]
+
+    with wave.open(inf, "rb") as wf:
+        c0 = wf.getnchannels()
+        fr = wf.getframerate()
+        sw = wf.getsampwidth()
+        nf = wf.getnframes()
+        wavdata = wf.readframes(nf * sw * c0)
+
+    if (c0 != 1):
+        raise RuntimeError("wt-tool only processes mono inputs")
+    if (fr != 44100):
+        raise RuntimeError("Please use 44.1k mono 16bit PCM wav files")
+    if (sw != 2):
+        raise RuntimeError("Please use 44.1k mono 16bit PCM wav files")
+
+    newrec = bytearray(len(wavdata))
+
+    if(options.normalize == "half"):
+        for i in range(int(len(wavdata) / 2)):
+            ls = wavdata[2 * i]
+            ms = wavdata[2 * i + 1]
+            if(ms >= 128):
+                ms -= 256
+            r = int((ls + ms * 256) / 2)
+
+            nls = int(r % 256)
+            nms = int(r / 256)
+
+            if(r < 0 and nls != 0):
+                nms -= 1
+            if(nms < 0):
+                nms += 256
+            newrec[2 * i] = nls
+            newrec[2 * i + 1] = nms
+
+    elif (options.normalize == "peak"):
+        peakp = 0
+        peakm = 0
+        d = wavdata
+        for i in range(int(len(d) / 2)):
+            ls = d[2 * i]
+            ms = d[2 * i + 1]
+            if(ms >= 128):
+                ms -= 256
+            r = int(ls + ms * 256)
+            if(r > peakp):
+                peakp = r
+            if(r < peakm):
+                peakm = r
+        if(-peakm > peakp):
+            peakp = -peakm
+        print("Peak value is ", peakp)
+        for i in range(int(len(d) / 2)):
+            ls = d[2 * i]
+            ms = d[2 * i + 1]
+            if(ms >= 128):
+                ms -= 256
+            r = int((ls + ms * 256) * 16384.0 / peakp)
+
+            nls = int(r % 256)
+            nms = int(r / 256)
+            if(r < 0 and nls != 0):
+                nms -= 1
+            if(nms < 0):
+                nms += 256
+            newrec[2 * i] = nls
+            newrec[2 * i + 1] = nms
+    else:
+        print("Unknown normalization ", options.normalize)
+        parser.print_help()
+
+    with wave.open(outf, "wb") as wav_file:
+        wav_file.setnchannels(1)
+        wav_file.setframerate(44100)
+        wav_file.setsampwidth(2)
+        wav_file.setnframes(int(len(newrec) / 2))
+
+        wav_file.writeframes(newrec)
+
+
+if __name__ == "__main__":
+    main()