fix(neutts): pin torchaudio to match torch to avoid ABI mismatch (#9798)

neucodec pulls torchaudio transitively but it was unpinned, so an
incompatible torchaudio could be resolved against the pinned torch==2.8.0,
producing the 'undefined symbol: torch_library_impl' load failure. Pin
torchaudio==2.8.0 alongside torch in the cpu and cublas12 requirements.

Assisted-by: claude:claude-opus-4-8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

backend/python/neutts/requirements-cpu.txt

@@ -1,6 +1,7 @@
 --extra-index-url https://download.pytorch.org/whl/cpu
 accelerate
 torch==2.8.0
+torchaudio==2.8.0
 transformers==4.56.1
 librosa==0.11.0
 neucodec>=0.0.4

backend/python/neutts/requirements-cublas12.txt

@@ -3,6 +3,7 @@ neucodec>=0.0.4
 phonemizer==3.3.0
 soundfile==0.13.1
 torch==2.8.0
+torchaudio==2.8.0
 transformers==4.56.1
 resemble-perth==1.0.1
 accelerate

core/http/endpoints/openai/realtime_webrtc.go

@@ -2,8 +2,6 @@ package openai
 
 import (
 	"net/http"
-	"runtime"
-	"strings"
 	"time"
 
 	"github.com/labstack/echo/v4"
@@ -13,52 +11,6 @@ import (
 	"github.com/pion/webrtc/v4"
 )
 
-// opusBackendName is the canonical gallery name/alias of the opus audio codec
-// backend that the realtime WebRTC transport needs.
-const opusBackendName = "opus"
-
-// resolveOpusBackend picks which installed opus-codec backend the realtime
-// WebRTC transport should load. The transport historically hardcoded the
-// literal "opus" backend name, but on darwin/arm64 the only installable opus
-// codec is "metal-opus" (it shares the gallery alias "opus"). When that
-// platform-specific variant is registered under its concrete directory name
-// rather than the "opus" alias key, loading the literal "opus" fails with
-// "opus backend not available" (issue #9813). Given the set of currently
-// loadable backend names, this returns the best opus codec to load for the
-// running platform, falling back to the literal name so the caller surfaces
-// the same error as before when no opus codec is installed at all.
-func resolveOpusBackend(installed []string, goos, goarch string) string {
-	// An exact match wins: this covers the plain "opus" backend as well as the
-	// "opus" alias key registered by gallery alias resolution for a
-	// user-installed platform variant.
-	for _, b := range installed {
-		if b == opusBackendName {
-			return opusBackendName
-		}
-	}
-
-	// No "opus" key is registered (e.g. a system-path metal-opus whose alias
-	// was never collected). Fall back to a platform-appropriate "*opus*" codec
-	// backend; on darwin/arm64 prefer the metal build.
-	var fallback string
-	for _, b := range installed {
-		if !strings.Contains(strings.ToLower(b), opusBackendName) {
-			continue
-		}
-		if goos == "darwin" && goarch == "arm64" && strings.Contains(strings.ToLower(b), "metal") {
-			return b
-		}
-		if fallback == "" {
-			fallback = b
-		}
-	}
-	if fallback != "" {
-		return fallback
-	}
-
-	return opusBackendName
-}
-
 // RealtimeCallRequest is the JSON body for POST /v1/realtime/calls.
 type RealtimeCallRequest struct {
 	SDP   string `json:"sdp"`
@@ -142,25 +94,15 @@ func RealtimeCalls(application *application.Application) echo.HandlerFunc {
 			}
 		}()
 
-		// Load the Opus backend. The opus codec ships under different backend
-		// names per platform (e.g. "metal-opus" on darwin/arm64), so resolve the
-		// platform-appropriate variant from the installed backends instead of
-		// hardcoding the literal "opus" name (issue #9813).
-		ml := application.ModelLoader()
-		installed := make([]string, 0)
-		for name := range ml.GetAllExternalBackends(nil) {
-			installed = append(installed, name)
-		}
-		opusName := resolveOpusBackend(installed, runtime.GOOS, runtime.GOARCH)
-
-		opusBackend, err := ml.Load(
-			model.WithBackendString(opusName),
+		// Load the Opus backend
+		opusBackend, err := application.ModelLoader().Load(
+			model.WithBackendString("opus"),
 			model.WithModelID("__opus_codec__"),
-			model.WithModel(opusName),
+			model.WithModel("opus"),
 		)
 		if err != nil {
 			pc.Close()
-			xlog.Error("failed to load opus backend", "error", err, "backend", opusName)
+			xlog.Error("failed to load opus backend", "error", err)
 			return c.JSON(http.StatusInternalServerError, map[string]string{"error": "opus backend not available"})
 		}
 

core/http/endpoints/openai/realtime_webrtc_opus_test.go

@@ -1,32 +0,0 @@
-package openai
-
-import (
-	. "github.com/onsi/ginkgo/v2"
-	. "github.com/onsi/gomega"
-)
-
-var _ = Describe("resolveOpusBackend", func() {
-	It("prefers the exact opus backend when it is installed", func() {
-		Expect(resolveOpusBackend([]string{"opus", "metal-opus"}, "linux", "amd64")).To(Equal("opus"))
-	})
-
-	It("resolves to the opus alias key on linux", func() {
-		Expect(resolveOpusBackend([]string{"opus"}, "linux", "amd64")).To(Equal("opus"))
-	})
-
-	It("selects metal-opus on darwin/arm64 when no plain opus is installed", func() {
-		Expect(resolveOpusBackend([]string{"metal-opus"}, "darwin", "arm64")).To(Equal("metal-opus"))
-	})
-
-	It("selects metal-opus on darwin/arm64 even when other backends are present", func() {
-		Expect(resolveOpusBackend([]string{"silero-vad", "metal-opus", "whisper"}, "darwin", "arm64")).To(Equal("metal-opus"))
-	})
-
-	It("falls back to any opus codec backend when there is no exact match (non-darwin)", func() {
-		Expect(resolveOpusBackend([]string{"metal-opus"}, "linux", "amd64")).To(Equal("metal-opus"))
-	})
-
-	It("returns the literal opus name when no opus codec is installed", func() {
-		Expect(resolveOpusBackend([]string{"silero-vad", "whisper"}, "darwin", "arm64")).To(Equal("opus"))
-	})
-})