install go2rtc on bob

2026-04-04 19:36:14 +02:00
parent f0b56e63d1
commit ccf88187b8
537 changed files with 69213 additions and 0 deletions
@@ -0,0 +1,51 @@
+// Package pcm
+// https://www.codeproject.com/Articles/14237/Using-the-G711-standard
+package pcm
+
+const bias = 0x84 // 132 or 1000 0100
+const ulawMax = alawMax - bias
+
+func PCMUtoPCM(ulaw byte) int16 {
+	ulaw = ^ulaw
+
+	exponent := (ulaw & 0x70) >> 4
+	data := (int16((((ulaw&0x0F)|0x10)<<1)+1) << (exponent + 2)) - bias
+
+	// sign
+	if ulaw&0x80 == 0 {
+		return data
+	} else if data == 0 {
+		return -1
+	} else {
+		return -data
+	}
+}
+
+func PCMtoPCMU(pcm int16) byte {
+	var ulaw byte
+
+	if pcm < 0 {
+		pcm = -pcm
+		ulaw = 0x80
+	}
+
+	if pcm > ulawMax {
+		pcm = ulawMax
+	}
+
+	pcm += bias
+
+	exponent := byte(7)
+	for expMask := int16(0x4000); (pcm & expMask) == 0; expMask >>= 1 {
+		exponent--
+	}
+
+	// mantisa
+	ulaw |= byte(pcm>>(exponent+3)) & 0x0F
+
+	if exponent > 0 {
+		ulaw |= exponent << 4
+	}
+
+	return ^ulaw
+}