feat: lot 433 — sound-design endpoint + 18 backends

POST /generate/sound-design — categories: texture, foley, impact,
transition, atmosphere, mechanical. AudioGen primary, ffmpeg fallback.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ai-bridge.js

@@ -71,7 +71,7 @@ const server = http.createServer(async (req, res) => {
 
   if (url.pathname === "/health") {
     res.writeHead(200, {"Content-Type":"application/json"});
-    res.end(JSON.stringify({ok:true,service:"ai-bridge",backends:["tts","musicgen","noise","ollama","drums","bass","pad","choir","fx","kokoro-tts","ace-step","demucs","drone","grain","glitch","circus","honk"]}));
+    res.end(JSON.stringify({ok:true,service:"ai-bridge",backends:["tts","musicgen","noise","ollama","drums","bass","pad","choir","fx","kokoro-tts","ace-step","demucs","drone","grain","glitch","circus","honk","sound-design"]}));
     return;
   }
   if (url.pathname === "/generate/music" && req.method === "POST") {
@@ -993,7 +993,63 @@ const server = http.createServer(async (req, res) => {
   }
 
 
-    // === Auto-Mastering (Matchering) ===
+  
+  // ── POST /generate/sound-design ──
+  // Sound design: generate sound effects, textures, foley using AudioGen/MusicGen
+  if (url.pathname === "/generate/sound-design" && req.method === "POST") {
+    const {prompt="atmospheric texture", duration=10, category="texture"} = JSON.parse(await readBody(req));
+    const categories = {
+      texture: "ambient texture, ",
+      foley: "foley sound effect, ",
+      impact: "cinematic impact hit, ",
+      transition: "sound transition whoosh, ",
+      atmosphere: "atmospheric soundscape, ",
+      mechanical: "mechanical industrial sound, ",
+    };
+    const prefix = categories[category] || categories.texture;
+    const fullPrompt = prefix + prompt;
+    try {
+      // Try AudioGen container first
+      const MUSICGEN_URL = "http://127.0.0.1:9000";
+      const r = await fetch(`${MUSICGEN_URL}/generate`, {
+        method: "POST",
+        headers: {"Content-Type": "application/json"},
+        body: JSON.stringify({prompt: fullPrompt, duration: Math.min(30, duration)}),
+        signal: AbortSignal.timeout(120000)
+      });
+      if (r.ok) {
+        const buf = Buffer.from(await r.arrayBuffer());
+        res.writeHead(200, {"Content-Type": "audio/wav", "Content-Length": buf.length, "X-Audio-Category": category});
+        res.end(buf);
+        return;
+      }
+      // Fallback: generate via ffmpeg synthesis
+      const out = tmpWav();
+      if (category === "impact") {
+        execFileSync("ffmpeg", ["-f", "lavfi", "-i",
+          `anoisesrc=d=0.2:c=white`, "-af",
+          `highpass=f=40,afade=t=out:st=0.03:d=0.17,apad=whole_dur=${duration},aecho=0.8:0.9:100|200:0.5|0.3,volume=0.7`,
+          "-t", String(duration), "-ar", "44100", "-ac", "2", "-y", out], {timeout: 15000});
+      } else if (category === "transition") {
+        execFileSync("ffmpeg", ["-f", "lavfi", "-i",
+          `aevalsrc='sin(2*PI*(200+3800*t/${duration})*t)*exp(-t*2)':s=44100:d=${duration}`,
+          "-af", "volume=0.6", "-ar", "44100", "-ac", "2", "-y", out], {timeout: 15000});
+      } else {
+        execFileSync("ffmpeg", ["-f", "lavfi", "-i",
+          `anoisesrc=d=${duration}:c=pink`, "-af",
+          `lowpass=f=3000,tremolo=f=0.2:d=0.5,afade=t=in:d=1,afade=t=out:st=${duration-2}:d=2,volume=0.5`,
+          "-ar", "44100", "-ac", "2", "-y", out], {timeout: 15000});
+      }
+      sendWav(res, out);
+    } catch(e) {
+      res.writeHead(500, {"Content-Type": "application/json"});
+      res.end(JSON.stringify({error: e.message}));
+    }
+    return;
+  }
+
+
+  // === Auto-Mastering (Matchering) ===
   if (url.pathname === "/master" && req.method === "POST") {
     const tmp_target = "/tmp/ai-master-target-" + Date.now() + ".wav";
     const tmp_ref = "/tmp/ai-master-ref-" + Date.now() + ".wav";
@@ -1013,6 +1069,27 @@ const server = http.createServer(async (req, res) => {
     }
     return;
   }
+  
+  // === Speech-to-Text (faster-whisper) ===
+  if (url.pathname === "/stt" && req.method === "POST") {
+    const tmp = "/tmp/stt-input-" + Date.now() + ".wav";
+    const pyScript = "/tmp/stt-run-" + Date.now() + ".py";
+    try {
+      const chunks = [];
+      await new Promise((resolve) => { req.on("data", d => chunks.push(d)); req.on("end", resolve); });
+      fs.writeFileSync(tmp, Buffer.concat(chunks));
+      fs.writeFileSync(pyScript, `from faster_whisper import WhisperModel\nm=WhisperModel("small",device="cpu",compute_type="int8")\nsegs,_=m.transcribe("${tmp}",language="fr")\nprint(" ".join(s.text for s in segs))`);
+      const result = execSync("/home/kxkm/venv/bin/python3 " + pyScript, {timeout:30000,encoding:"utf8"});
+      fs.unlinkSync(tmp); fs.unlinkSync(pyScript);
+      res.writeHead(200,{"Content-Type":"application/json"});
+      res.end(JSON.stringify({ok:true,text:result.trim()}));
+    } catch(e) {
+      try{fs.unlinkSync(tmp)}catch{} try{fs.unlinkSync(pyScript)}catch{}
+      res.writeHead(500,{"Content-Type":"application/json"});
+      res.end(JSON.stringify({error:e.message}));
+    }
+    return;
+  }
   res.writeHead(404); res.end("Not found");
 });
-server.listen(PORT, () => console.log(`[ai-bridge] :${PORT} — instruments: drums, bass, pad, choir, fx, drone, grain, glitch, circus, honk`));
+server.listen(PORT, () => console.log(`[ai-bridge] :${PORT} — instruments: drums, bass, pad, choir, fx, drone, grain, glitch, circus, honk, sound-design`));