feat(capability): 转码能力包（vendor 纯 Go AMR-NB 解码器 + 黄金向量逐样本对照 + 8 哨兵 + 注册面）

internal/capability/transcode/amrnb/dsp_enc_lsp.go

@@ -0,0 +1,54 @@
+package amrnb
+
+// Encoder LSP analysis/quantization wrapper, ported from opencore-amrnb lsp.cpp
+// (lsp). Per frame it converts the analysis A(z) to LSPs (azLsp), quantizes them
+// (qPlsf3/qPlsf5), and interpolates both the unquantized LP filters (az, for the
+// perceptual weighting) and the quantized ones (azQ, for synthesis) across the
+// four subframes, returning the LSF codebook indices. Bit-exact with the
+// reference.
+
+// lspEncState holds the encoder's LSP predictor memories.
+type lspEncState struct {
+	lspOld  [cM]int16
+	lspOldQ [cM]int16
+	q       qPlsfState
+}
+
+func (st *lspEncState) reset() {
+	copy(st.lspOld[:], lsp_init_data[:cM])
+	copy(st.lspOldQ[:], lsp_init_data[:cM])
+	st.q.reset()
+}
+
+// lsp processes one frame's LP analysis. az holds the unquantized A(z) with the
+// per-window filters already placed (A_mid at [MP1] for MR122, A_new at [3*MP1]);
+// on return az and azQ hold the interpolated unquantized/quantized filters for
+// all four subframes. The LSF indices are written to anap; the count is
+// returned. Mirrors lsp.
+func (st *lspEncState) lsp(mode int, az, azQ, anap []int16) int {
+	var lspNew [cM]int16
+	if mode == dMR122 {
+		var lspMid, lspMidQ, lspNewQ [cM]int16
+		azLsp(az[cMP1:], lspMid[:], st.lspOld[:])
+		azLsp(az[3*cMP1:], lspNew[:], lspMid[:])
+		intLpc1and3_2(st.lspOld[:], lspMid[:], lspNew[:], az)
+
+		idx := st.q.qPlsf5(lspMid[:], lspNew[:], lspMidQ[:], lspNewQ[:])
+		intLpc1and3(st.lspOldQ[:], lspMidQ[:], lspNewQ[:], azQ)
+		copy(anap[:5], idx[:])
+		copy(st.lspOldQ[:], lspNewQ[:])
+		copy(st.lspOld[:], lspNew[:])
+		return 5
+	}
+
+	var lspNewQ [cM]int16
+	azLsp(az[3*cMP1:], lspNew[:], st.lspOld[:])
+	intLpc1to3_2(st.lspOld[:], lspNew[:], az)
+
+	idx := st.q.qPlsf3(mode, lspNew[:], lspNewQ[:])
+	intLpc1to3(st.lspOldQ[:], lspNewQ[:], azQ)
+	copy(anap[:3], idx[:])
+	copy(st.lspOldQ[:], lspNewQ[:])
+	copy(st.lspOld[:], lspNew[:])
+	return 3
+}