新增pcm转711方法

star_lock/lib/talk/call/g711Encode.dart

@@ -33,4 +33,37 @@ class G711Decoder {
 
     return Uint8List.fromList(g711Data);
   }
+
+  List<int> pcm16ToG711u(List<int> pcm16Data) {
+    List<int> g711uData = [];
+
+    for (int i = 0; i < pcm16Data.length; i += 2) {
+      int pcmSample = (pcm16Data[i + 1] << 8) | pcm16Data[i];
+      int g711Sample = pcmToG711u(pcmSample);
+
+      // 将 G.711 样本拆分成两个字节
+      g711uData.add(g711Sample & 0xFF);
+      g711uData.add((g711Sample >> 8) & 0xFF);
+    }
+
+    return g711uData;
+  }
+
+  int pcmToG711u(int pcmSample) {
+    const int MULAW_BIAS = 0x84;
+    const int CLIP = 32635;
+
+    // 剪裁 PCM 样本
+    if (pcmSample > CLIP) {
+      pcmSample = CLIP;
+    } else if (pcmSample < -CLIP) {
+      pcmSample = -CLIP;
+    }
+
+    // 增加偏置并取反
+    pcmSample += MULAW_BIAS;
+    pcmSample = ~pcmSample & 0xFF;
+
+    return pcmSample;
+  }
 }