audio/diarize.go

@@ -0,0 +1,113 @@
+package audio
+
+import "context"
+
+// DiarizationRequest is a speaker-labelled transcription request ("who said
+// what"). Audio is carried as bytes (never a URL), mirroring
+// TranscriptionRequest. Zero values mean "backend default" (ADR-0020).
+type DiarizationRequest struct {
+	// Audio is the encoded audio (or video container) to transcribe.
+	Audio []byte
+
+	// MIME is the audio MIME type (e.g. "audio/mpeg"); "" = let the backend
+	// sniff it.
+	MIME string
+
+	// Filename is the multipart filename hint some backends key their format
+	// detection on; "" derives one from MIME or falls back to "audio".
+	Filename string
+
+	// Language is a BCP-47/ISO-639 hint (e.g. "en"); "" = auto-detect.
+	Language string
+
+	// MinSpeakers / MaxSpeakers bound the speaker count when the caller knows
+	// it; 0 = let the backend estimate.
+	MinSpeakers int
+	MaxSpeakers int
+}
+
+// DiarizationSegment is one speaker turn.
+type DiarizationSegment struct {
+	// Start and End are offsets into the audio, in seconds.
+	Start float64
+	End   float64
+
+	// Speaker is the backend's per-file speaker label (e.g. "SPEAKER_00").
+	// Labels are relative to this one file — they are NOT stable identities
+	// across files.
+	Speaker string
+
+	// Text is the transcript of this turn.
+	Text string
+}
+
+// DiarizationResult is the canonical diarization result.
+type DiarizationResult struct {
+	// Text is the full transcript, unlabelled.
+	Text string
+
+	// Language is the detected (or requested) language code; may be "".
+	Language string
+
+	// Segments are the speaker turns in time order.
+	Segments []DiarizationSegment
+
+	// Raw is the provider-native response object. May be nil.
+	Raw any
+}
+
+// DiarizationOption mutates a DiarizationRequest before it is sent.
+type DiarizationOption func(*DiarizationRequest)
+
+// WithDiarizationLanguage sets the language hint (e.g. "en").
+func WithDiarizationLanguage(l string) DiarizationOption {
+	return func(r *DiarizationRequest) { r.Language = l }
+}
+
+// WithSpeakerBounds bounds the expected speaker count (0 leaves a bound
+// unset).
+func WithSpeakerBounds(minSpeakers, maxSpeakers int) DiarizationOption {
+	return func(r *DiarizationRequest) {
+		r.MinSpeakers, r.MaxSpeakers = minSpeakers, maxSpeakers
+	}
+}
+
+// Apply returns a copy of the request with all options applied.
+func (r DiarizationRequest) Apply(opts ...DiarizationOption) DiarizationRequest {
+	for _, opt := range opts {
+		opt(&r)
+	}
+	return r
+}
+
+// DiarizationModel transcribes audio with speaker labels.
+type DiarizationModel interface {
+	// Diarize converts the request's audio into speaker-labelled segments.
+	Diarize(ctx context.Context, req DiarizationRequest, opts ...DiarizationOption) (*DiarizationResult, error)
+}
+
+// DiarizationModelOption configures a DiarizationModel at construction time.
+// Reserved for future per-model settings.
+type DiarizationModelOption func(*DiarizationModelConfig)
+
+// DiarizationModelConfig carries per-model construction settings.
+type DiarizationModelConfig struct{}
+
+// ApplyDiarizationModelOptions folds options into a config.
+func ApplyDiarizationModelOptions(opts []DiarizationModelOption) DiarizationModelConfig {
+	var cfg DiarizationModelConfig
+	for _, opt := range opts {
+		opt(&cfg)
+	}
+	return cfg
+}
+
+// DiarizationProvider mints diarization models bound to one backend.
+type DiarizationProvider interface {
+	// Name is the registry identifier for the provider.
+	Name() string
+
+	// DiarizationModel returns a DiarizationModel bound to the given id
+	// (passed through to the backend verbatim; no catalog validation).
+	DiarizationModel(id string, opts ...DiarizationModelOption) (DiarizationModel, error)
+}

docs/adr/0020-upstream-passthrough-media-surfaces.md

@@ -0,0 +1,62 @@
+# ADR-0020: Upstream-passthrough media surfaces (mask, upscale, background removal, interpolation, diarization, meshgen)
+
+Status: Accepted (2026-07-12)
+
+## Context
+
+The llama-swap host is growing capabilities whose native HTTP APIs are not
+OpenAI-shaped and carry no routable `model` field: rembg (`/api/remove`),
+a Real-ESRGAN+RIFE shim (`/v1/upscale`, `/v1/interpolate`), a WhisperX
+diarization sidecar (`/asr?diarize=true`), and Hunyuan3D (`/generate`).
+llama-swap's fork already exposes a generic passthrough —
+`/upstream/<model>/<any path>` — that pins the model, runs the normal
+load/swap queue, and proxies the rest of the path verbatim.
+
+Separately, sd-server's `/sdapi/v1/img2img` accepts an inpainting `mask`
+field that `imagegen.EditRequest` could not express.
+
+## Decision
+
+1. **Route odd-shaped upstreams through `/upstream/<model>/<path>`** via a
+   shared `upstreamPath` helper (model-id validation identical to `Unload`:
+   reject `/?#`, never escape). No per-endpoint llama-swap routes; the
+   passthrough is the contract.
+2. **Grow the existing leaf contracts instead of inventing parallel ones**,
+   keeping the ADR-0016→0019 conventions (functional options, zero value =
+   backend default, bytes-only I/O, `Raw` escape hatch, provider mints
+   model):
+   - `imagegen.EditRequest.Mask` (white = repaint, black = keep; backends
+     without mask support must reject, not ignore).
+   - `imagegen.Upscaler` / `UpscaleProvider` — super-resolution is not a
+     diffusion model, so it binds its own backend id.
+   - `imagegen.BackgroundRemover` / `BackgroundRemovalProvider` — request
+     `Net` selects the remover's internal network (rembg `model=` param);
+     `OnlyMask` returns the segmentation mask (the natural mask source for
+     inpainting).
+   - `videogen.Interpolator` / `InterpolationProvider` — fps boost or
+     slow-mo (`SlowMo` plays synthesized frames at the source rate; audio
+     stripped by the backend in that mode).
+   - `audio.DiarizationModel` / `DiarizationProvider` — speaker-labelled
+     segments; per-file `SPEAKER_NN` labels are explicitly NOT stable
+     identities.
+3. **New `meshgen` leaf package** for image→3D (`Mesh{Data, Format, MIME}`,
+   formats glb/stl/obj). Image-to-3D only: text-to-3D is the caller-owned
+   composition imagegen → meshgen.
+4. **Binary success bodies are validated before wrapping**: one-image
+   results reject non-image payloads, interpolation reuses the videogen
+   MIME rules and 512MB cap, meshes reject JSON-shaped "success" bodies
+   (a queue-full detail page must never become "the mesh"), and
+   diarization requires `output=json` because the vtt/srt shapes drop
+   speaker labels.
+
+## Consequences
+
+- provider/llamaswap gains five surfaces with no new wire machinery beyond
+  `upstreamPath` + a shared one-file-multipart builder.
+- The passthrough couples majordomo to the fork's `/upstream` route
+  (upstream llama-swap has it too) and to each upstream's native API shape;
+  those shapes are pinned by the netherstorm image builds, not by version
+  negotiation — smoke tests on the host are the drift defence.
+- `upstream.ignorePaths` (llama-swap config) can 409 asset-looking paths on
+  cold models; none of the paths used here match the default pattern, but
+  new surfaces must check.

imagegen/background.go

@@ -0,0 +1,76 @@
+package imagegen
+
+import "context"
+
+// BackgroundRemovalRequest asks a matting/segmentation backend to cut the
+// subject out of an image. Zero values mean "backend default" (ADR-0020).
+type BackgroundRemovalRequest struct {
+	// Image is the image to process. Required.
+	Image Image
+
+	// Net selects the remover's internal network where the backend offers
+	// several (rembg: "u2net", "birefnet-general", "isnet-general-use", ...);
+	// "" = backend default. This is NOT the provider model id — that is fixed
+	// when the BackgroundRemover is minted.
+	Net string
+
+	// OnlyMask returns the black/white segmentation mask instead of the
+	// cutout — white where the subject is. Useful as an inpainting mask
+	// (EditRequest.Mask semantics after inversion: the mask marks the
+	// FOREGROUND, an inpaint mask marks the region to REPAINT).
+	OnlyMask bool
+}
+
+// BackgroundRemovalOption mutates a BackgroundRemovalRequest before it is sent.
+type BackgroundRemovalOption func(*BackgroundRemovalRequest)
+
+// WithBackgroundNet selects the remover's internal network.
+func WithBackgroundNet(n string) BackgroundRemovalOption {
+	return func(r *BackgroundRemovalRequest) { r.Net = n }
+}
+
+// WithOnlyMask requests the segmentation mask instead of the cutout.
+func WithOnlyMask() BackgroundRemovalOption {
+	return func(r *BackgroundRemovalRequest) { r.OnlyMask = true }
+}
+
+// Apply returns a copy of the request with all options applied.
+func (r BackgroundRemovalRequest) Apply(opts ...BackgroundRemovalOption) BackgroundRemovalRequest {
+	for _, opt := range opts {
+		opt(&r)
+	}
+	return r
+}
+
+// BackgroundRemover cuts subjects out of images (RGBA PNG with transparent
+// background, or the mask alone with OnlyMask).
+type BackgroundRemover interface {
+	// RemoveBackground returns the cutout (or mask) as a one-image Result.
+	RemoveBackground(ctx context.Context, req BackgroundRemovalRequest, opts ...BackgroundRemovalOption) (*Result, error)
+}
+
+// BackgroundRemovalModelOption configures a BackgroundRemover at construction
+// time. Reserved for future per-model settings.
+type BackgroundRemovalModelOption func(*BackgroundRemovalModelConfig)
+
+// BackgroundRemovalModelConfig carries per-model construction settings.
+type BackgroundRemovalModelConfig struct{}
+
+// ApplyBackgroundRemovalModelOptions folds options into a config.
+func ApplyBackgroundRemovalModelOptions(opts []BackgroundRemovalModelOption) BackgroundRemovalModelConfig {
+	var cfg BackgroundRemovalModelConfig
+	for _, opt := range opts {
+		opt(&cfg)
+	}
+	return cfg
+}
+
+// BackgroundRemovalProvider mints BackgroundRemovers bound to one backend.
+type BackgroundRemovalProvider interface {
+	// Name is the registry identifier for the provider.
+	Name() string
+
+	// BackgroundRemovalModel returns a BackgroundRemover bound to the given
+	// id (passed through to the backend verbatim; no catalog validation).
+	BackgroundRemovalModel(id string, opts ...BackgroundRemovalModelOption) (BackgroundRemover, error)
+}

imagegen/edit.go

@@ -12,6 +12,12 @@ type EditRequest struct {
 	// Init is the initial image the edit starts from. Required.
 	Init Image
 
+	// Mask restricts the edit to a region (inpainting): a single-channel or
+	// RGB image the same size as Init where WHITE pixels are repainted and
+	// BLACK pixels are kept. Empty = whole-image edit. Backends without mask
+	// support must reject a masked request rather than silently ignoring it.
+	Mask Image
+
 	// Strength is the denoising strength in [0,1] — how far the result may
 	// depart from Init (0 = return the input, 1 = ignore it); nil = backend
 	// default.
@@ -45,6 +51,9 @@ type EditRequest struct {
 // are applied to a copy of the request, so an EditRequest value can be reused.
 type EditOption func(*EditRequest)
 
+// WithEditMask restricts the edit to a region (white = repaint, black = keep).
+func WithEditMask(m Image) EditOption { return func(r *EditRequest) { r.Mask = m } }
+
 // WithEditStrength sets the denoising strength in [0,1].
 func WithEditStrength(s float64) EditOption { return func(r *EditRequest) { r.Strength = &s } }
 

imagegen/upscale.go

@@ -0,0 +1,62 @@
+package imagegen
+
+import "context"
+
+// UpscaleRequest asks a super-resolution backend to enlarge an image. Zero
+// values mean "backend default", mirroring EditRequest (ADR-0020).
+type UpscaleRequest struct {
+	// Image is the image to upscale. Required.
+	Image Image
+
+	// Scale is the enlargement factor (2 or 4 on the reference backend);
+	// 0 = backend default.
+	Scale int
+}
+
+// UpscaleOption mutates an UpscaleRequest before it is sent.
+type UpscaleOption func(*UpscaleRequest)
+
+// WithUpscaleScale sets the enlargement factor.
+func WithUpscaleScale(s int) UpscaleOption { return func(r *UpscaleRequest) { r.Scale = s } }
+
+// Apply returns a copy of the request with all options applied.
+func (r UpscaleRequest) Apply(opts ...UpscaleOption) UpscaleRequest {
+	for _, opt := range opts {
+		opt(&r)
+	}
+	return r
+}
+
+// Upscaler enlarges images with a super-resolution model. It is its own
+// small interface (not a method on Model) because upscalers are not
+// diffusion models — they bind to a different backend id entirely.
+type Upscaler interface {
+	// Upscale returns the enlarged image (a one-image Result).
+	Upscale(ctx context.Context, req UpscaleRequest, opts ...UpscaleOption) (*Result, error)
+}
+
+// UpscaleModelOption configures an Upscaler at construction time. Reserved
+// for future per-model settings (mirrors ModelOption).
+type UpscaleModelOption func(*UpscaleModelConfig)
+
+// UpscaleModelConfig carries per-model construction settings.
+type UpscaleModelConfig struct{}
+
+// ApplyUpscaleModelOptions folds options into a config.
+func ApplyUpscaleModelOptions(opts []UpscaleModelOption) UpscaleModelConfig {
+	var cfg UpscaleModelConfig
+	for _, opt := range opts {
+		opt(&cfg)
+	}
+	return cfg
+}
+
+// UpscaleProvider mints Upscalers bound to one backend.
+type UpscaleProvider interface {
+	// Name is the registry identifier for the provider.
+	Name() string
+
+	// UpscaleModel returns an Upscaler bound to the given id (passed through
+	// to the backend verbatim; no catalog validation).
+	UpscaleModel(id string, opts ...UpscaleModelOption) (Upscaler, error)
+}

meshgen/meshgen.go

@@ -0,0 +1,152 @@
+// Package meshgen is majordomo's canonical image-to-3D surface. Like
+// imagegen/audio/videogen, it is a deliberately separate leaf contract from
+// the llm package: mesh generation shares none of the chat machinery, so it
+// gets its own small Provider/Model interfaces (ADR-0020, following the
+// ADR-0016→0019 lineage: functional options, zero values = backend default,
+// bytes-only I/O, Raw escape hatch).
+//
+// The first implementation is provider/llamaswap, which targets a
+// Hunyuan3D-2.1-style api_server reached through the /upstream passthrough.
+// The surface is image-to-3D only: text-to-3D is the composition
+// imagegen.Generate → meshgen.Generate, owned by the caller.
+package meshgen
+
+import (
+	"context"
+
+	"gitea.stevedudenhoeffer.com/steve/majordomo/llm"
+)
+
+// Image is the conditioning input (bytes + MIME), aliased to llm.ImagePart so
+// chat- or imagegen-sourced images feed mesh generation without conversion.
+type Image = llm.ImagePart
+
+// Mesh is one generated 3D asset: raw encoded bytes plus its format.
+type Mesh struct {
+	// Data is the encoded mesh (binary GLB/STL/OBJ container).
+	Data []byte
+
+	// Format is the lowercase container name ("glb", "stl", "obj").
+	Format string
+
+	// MIME is the corresponding MIME type, e.g. "model/gltf-binary",
+	// "model/stl".
+	MIME string
+}
+
+// Request is an image-to-3D generation request. Zero values mean "backend
+// default".
+type Request struct {
+	// Image is the source image the mesh is reconstructed from. Required.
+	Image Image
+
+	// Format is the requested output container ("glb", "stl", "obj");
+	// "" = backend default (glb).
+	Format string
+
+	// Texture asks the backend to also synthesize surface textures. Much
+	// slower and much more VRAM-hungry than shape-only on the reference
+	// backend; leave false for print-pipeline geometry.
+	Texture bool
+
+	// RemoveBackground lets the backend cut the subject out first; nil =
+	// backend default (true on Hunyuan3D). Set explicitly to false when the
+	// input is already a clean cutout.
+	RemoveBackground *bool
+
+	// OctreeResolution is the shape-decoder grid resolution; 0 = backend
+	// default.
+	OctreeResolution int
+
+	// Steps is the number of diffusion steps; nil = backend default.
+	Steps *int
+
+	// GuidanceScale is the guidance strength; nil = backend default.
+	GuidanceScale *float64
+
+	// Seed fixes the RNG seed for reproducible output; nil = backend default.
+	Seed *int64
+
+	// FaceCount caps the output mesh's face count; 0 = backend default.
+	FaceCount int
+}
+
+// Result is the canonical mesh-generation result.
+type Result struct {
+	// Mesh is the generated asset.
+	Mesh Mesh
+
+	// Raw is the provider-native response object. May be nil.
+	Raw any
+}
+
+// Option mutates a Request before it is sent. Options passed to Generate are
+// applied to a copy of the request, so a Request value can be reused.
+type Option func(*Request)
+
+// WithFormat sets the output container ("glb", "stl", "obj").
+func WithFormat(f string) Option { return func(r *Request) { r.Format = f } }
+
+// WithTexture enables texture synthesis.
+func WithTexture() Option { return func(r *Request) { r.Texture = true } }
+
+// WithRemoveBackground sets the backend's background-removal preprocessing.
+func WithRemoveBackground(v bool) Option {
+	return func(r *Request) { r.RemoveBackground = &v }
+}
+
+// WithOctreeResolution sets the shape-decoder grid resolution.
+func WithOctreeResolution(n int) Option { return func(r *Request) { r.OctreeResolution = n } }
+
+// WithSteps overrides the number of diffusion steps.
+func WithSteps(n int) Option { return func(r *Request) { r.Steps = &n } }
+
+// WithGuidanceScale overrides the guidance strength.
+func WithGuidanceScale(s float64) Option { return func(r *Request) { r.GuidanceScale = &s } }
+
+// WithSeed fixes the RNG seed.
+func WithSeed(seed int64) Option { return func(r *Request) { r.Seed = &seed } }
+
+// WithFaceCount caps the output mesh's face count.
+func WithFaceCount(n int) Option { return func(r *Request) { r.FaceCount = n } }
+
+// Apply returns a copy of the request with all options applied. Providers
+// call this once at the top of Generate.
+func (r Request) Apply(opts ...Option) Request {
+	for _, opt := range opts {
+		opt(&r)
+	}
+	return r
+}
+
+// Model generates 3D meshes from images.
+type Model interface {
+	// Generate reconstructs a mesh from the request's image.
+	Generate(ctx context.Context, req Request, opts ...Option) (*Result, error)
+}
+
+// ModelOption configures a Model at construction time. Reserved for future
+// per-model settings.
+type ModelOption func(*ModelConfig)
+
+// ModelConfig carries per-model construction settings.
+type ModelConfig struct{}
+
+// ApplyModelOptions folds options into a config.
+func ApplyModelOptions(opts []ModelOption) ModelConfig {
+	var cfg ModelConfig
+	for _, opt := range opts {
+		opt(&cfg)
+	}
+	return cfg
+}
+
+// Provider mints mesh models bound to one backend.
+type Provider interface {
+	// Name is the registry identifier for the provider.
+	Name() string
+
+	// MeshModel returns a Model bound to the given id (passed through to the
+	// backend verbatim; no catalog validation).
+	MeshModel(id string, opts ...ModelOption) (Model, error)
+}

provider/llamaswap/diarize.go

@@ -0,0 +1,122 @@
+// diarize.go implements audio.DiarizationProvider against a
+// whisper-asr-webservice upstream (WhisperX engine) reached through
+// llama-swap's /upstream passthrough (ADR-0020):
+//
+//	POST /upstream/<id>/asr?output=json&diarize=true[&language&min_speakers&max_speakers]
+//
+// output=json is load-bearing: the vtt/srt output formats DROP the speaker
+// labels; only the json shape carries per-segment `speaker` fields.
+package llamaswap
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strconv"
+
+	"gitea.stevedudenhoeffer.com/steve/majordomo/audio"
+	"gitea.stevedudenhoeffer.com/steve/majordomo/llm"
+)
+
+// DiarizationModel implements audio.DiarizationProvider. The id selects
+// which upstream llama-swap loads (the pyannote-equipped WhisperX sidecar,
+// not the plain whisper.cpp model).
+func (p *Provider) DiarizationModel(id string, opts ...audio.DiarizationModelOption) (audio.DiarizationModel, error) {
+	if err := p.requireBaseURL(); err != nil {
+		return nil, err
+	}
+	_ = audio.ApplyDiarizationModelOptions(opts)
+	return &diarizationModel{p: p, id: id}, nil
+}
+
+type diarizationModel struct {
+	p  *Provider
+	id string
+}
+
+// asrResponse is whisper-asr-webservice's output=json shape (the subset this
+// package relies on; per-word entries are ignored — segment granularity is
+// the contract).
+type asrResponse struct {
+	Text     string `json:"text"`
+	Language string `json:"language"`
+	Segments []struct {
+		Start   float64 `json:"start"`
+		End     float64 `json:"end"`
+		Text    string  `json:"text"`
+		Speaker string  `json:"speaker"`
+	} `json:"segments"`
+}
+
+// Diarize implements audio.DiarizationModel.
+func (m *diarizationModel) Diarize(ctx context.Context, req audio.DiarizationRequest, opts ...audio.DiarizationOption) (*audio.DiarizationResult, error) {
+	req = req.Apply(opts...)
+	if len(req.Audio) == 0 {
+		return nil, fmt.Errorf("%w: diarization requires audio bytes", llm.ErrUnsupported)
+	}
+	if req.MinSpeakers < 0 || req.MaxSpeakers < 0 ||
+		(req.MaxSpeakers > 0 && req.MinSpeakers > req.MaxSpeakers) {
+		return nil, fmt.Errorf("%w: invalid speaker bounds [%d,%d]", llm.ErrUnsupported, req.MinSpeakers, req.MaxSpeakers)
+	}
+
+	q := url.Values{}
+	q.Set("output", "json")
+	q.Set("diarize", "true")
+	if req.Language != "" {
+		q.Set("language", req.Language)
+	}
+	if req.MinSpeakers > 0 {
+		q.Set("min_speakers", strconv.Itoa(req.MinSpeakers))
+	}
+	if req.MaxSpeakers > 0 {
+		q.Set("max_speakers", strconv.Itoa(req.MaxSpeakers))
+	}
+	path, err := upstreamPath(m.id, "/asr?"+q.Encode())
+	if err != nil {
+		return nil, err
+	}
+
+	body, contentType, err := buildMultipart("build diarization form",
+		filePart{field: "audio_file", filename: diarizationFilename(req), data: req.Audio},
+		nil)
+	if err != nil {
+		return nil, err
+	}
+	raw, _, err := m.p.doRaw(ctx, http.MethodPost, path, m.id, contentType, body, maxResponseBytes)
+	if err != nil {
+		return nil, err
+	}
+
+	var out asrResponse
+	if err := json.Unmarshal(raw, &out); err != nil {
+		return nil, fmt.Errorf("llama-swap: decode diarization response: %w", err)
+	}
+	res := &audio.DiarizationResult{
+		Text:     out.Text,
+		Language: out.Language,
+		Raw:      json.RawMessage(raw),
+	}
+	for _, s := range out.Segments {
+		res.Segments = append(res.Segments, audio.DiarizationSegment{
+			Start:   s.Start,
+			End:     s.End,
+			Speaker: s.Speaker,
+			Text:    s.Text,
+		})
+	}
+	if len(res.Segments) == 0 && res.Text == "" {
+		return nil, &llm.APIError{Provider: m.p.name, Model: m.id, Message: "diarization response contained no transcript"}
+	}
+	return res, nil
+}
+
+// diarizationFilename mirrors transcriptionFilename for the diarization
+// request shape (same untrusted-metadata sanitization rules).
+func diarizationFilename(req audio.DiarizationRequest) string {
+	return transcriptionFilename(audio.TranscriptionRequest{
+		Filename: req.Filename,
+		MIME:     req.MIME,
+	})
+}

provider/llamaswap/edit_test.go

@@ -108,3 +108,47 @@ func TestImageEditValidation(t *testing.T) {
 		t.Errorf("out-of-range strength: err = %v, want ErrUnsupported", err)
 	}
 }
+
+func TestImageEditWithMask(t *testing.T) {
+	var gotBody map[string]any
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_ = json.NewDecoder(r.Body).Decode(&gotBody)
+		_, _ = w.Write([]byte(`{"images":["` + onePixelPNG + `"]}`))
+	}))
+	defer srv.Close()
+
+	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
+	im, _ := p.ImageModel("sd")
+	ed := im.(imagegen.Editor)
+
+	mask := imagegen.Image{MIME: "image/png", Data: []byte{0xDE, 0xAD}}
+	if _, err := ed.Edit(context.Background(),
+		imagegen.EditRequest{Prompt: "replace the sky", Init: editInit(t)},
+		imagegen.WithEditMask(mask),
+	); err != nil {
+		t.Fatalf("Edit: %v", err)
+	}
+	if got := gotBody["mask"]; got != base64.StdEncoding.EncodeToString(mask.Data) {
+		t.Errorf("mask = %v, want the b64 mask", got)
+	}
+}
+
+func TestImageEditWithoutMaskOmitsField(t *testing.T) {
+	var gotBody map[string]any
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_ = json.NewDecoder(r.Body).Decode(&gotBody)
+		_, _ = w.Write([]byte(`{"images":["` + onePixelPNG + `"]}`))
+	}))
+	defer srv.Close()
+
+	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
+	im, _ := p.ImageModel("sd")
+	ed := im.(imagegen.Editor)
+	if _, err := ed.Edit(context.Background(),
+		imagegen.EditRequest{Prompt: "p", Init: editInit(t)}); err != nil {
+		t.Fatalf("Edit: %v", err)
+	}
+	if _, ok := gotBody["mask"]; ok {
+		t.Error("mask field sent for unmasked edit; want omitted")
+	}
+}

provider/llamaswap/image.go

@@ -128,6 +128,11 @@ type img2imgRequest struct {
 	txt2imgRequest
 	InitImages        []string `json:"init_images"`
 	DenoisingStrength *float64 `json:"denoising_strength,omitempty"`
+	// Mask enables inpainting: base64 image, white = repaint, black = keep
+	// (sd-server also accepts a data URL; plain base64 keeps symmetry with
+	// init_images). sd-server has no mask_blur/inpaint_full_res — callers
+	// wanting soft edges pre-feather the mask.
+	Mask string `json:"mask,omitempty"`
 }
 
 // Edit implements imagegen.Editor via POST {base}/sdapi/v1/img2img.
@@ -148,6 +153,9 @@ func (m *imageModel) Edit(ctx context.Context, req imagegen.EditRequest, opts ..
 		InitImages:        []string{base64.StdEncoding.EncodeToString(req.Init.Data)},
 		DenoisingStrength: req.Strength,
 	}
+	if len(req.Mask.Data) > 0 {
+		wire.Mask = base64.StdEncoding.EncodeToString(req.Mask.Data)
+	}
 
 	var resp txt2imgResponse
 	if err := m.p.doJSON(ctx, http.MethodPost, "/sdapi/v1/img2img", m.id, &wire, &resp); err != nil {

provider/llamaswap/mediautil.go

@@ -0,0 +1,204 @@
+// mediautil.go implements the imagegen.UpscaleProvider,
+// imagegen.BackgroundRemovalProvider, and videogen.InterpolationProvider
+// surfaces against upstreams reached through llama-swap's /upstream
+// passthrough (ADR-0020):
+//
+//	upscale      POST /upstream/<id>/v1/upscale       (mediautils shim)
+//	background   POST /upstream/<id>/api/remove       (rembg server)
+//	interpolate  POST /upstream/<id>/v1/interpolate   (mediautils shim)
+//
+// All three are one-file multipart in, raw bytes out.
+package llamaswap
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"gitea.stevedudenhoeffer.com/steve/majordomo/imagegen"
+	"gitea.stevedudenhoeffer.com/steve/majordomo/llm"
+	"gitea.stevedudenhoeffer.com/steve/majordomo/videogen"
+)
+
+// --- upscale ---
+
+// UpscaleModel implements imagegen.UpscaleProvider against the mediautils
+// shim's POST /v1/upscale. The id selects which upstream llama-swap loads.
+func (p *Provider) UpscaleModel(id string, opts ...imagegen.UpscaleModelOption) (imagegen.Upscaler, error) {
+	if err := p.requireBaseURL(); err != nil {
+		return nil, err
+	}
+	_ = imagegen.ApplyUpscaleModelOptions(opts)
+	return &upscaleModel{p: p, id: id}, nil
+}
+
+type upscaleModel struct {
+	p  *Provider
+	id string
+}
+
+// Upscale implements imagegen.Upscaler.
+func (m *upscaleModel) Upscale(ctx context.Context, req imagegen.UpscaleRequest, opts ...imagegen.UpscaleOption) (*imagegen.Result, error) {
+	req = req.Apply(opts...)
+	if len(req.Image.Data) == 0 {
+		return nil, fmt.Errorf("%w: upscale requires an image", llm.ErrUnsupported)
+	}
+	if req.Scale != 0 && req.Scale != 2 && req.Scale != 4 {
+		return nil, fmt.Errorf("%w: upscale scale must be 2 or 4, got %d", llm.ErrUnsupported, req.Scale)
+	}
+	path, err := upstreamPath(m.id, "/v1/upscale")
+	if err != nil {
+		return nil, err
+	}
+	scale := ""
+	if req.Scale != 0 {
+		scale = strconv.Itoa(req.Scale)
+	}
+	body, contentType, err := buildMultipart("build upscale form",
+		filePart{field: "file", filename: "image.png", data: req.Image.Data},
+		[]formField{{"scale", scale, false}})
+	if err != nil {
+		return nil, err
+	}
+	raw, respType, err := m.p.doRaw(ctx, http.MethodPost, path, m.id, contentType, body, maxResponseBytes)
+	if err != nil {
+		return nil, err
+	}
+	return singleImageResult(m.p.name, m.id, "upscale", raw, respType)
+}
+
+// --- background removal ---
+
+// BackgroundRemovalModel implements imagegen.BackgroundRemovalProvider
+// against a rembg server's POST /api/remove.
+func (p *Provider) BackgroundRemovalModel(id string, opts ...imagegen.BackgroundRemovalModelOption) (imagegen.BackgroundRemover, error) {
+	if err := p.requireBaseURL(); err != nil {
+		return nil, err
+	}
+	_ = imagegen.ApplyBackgroundRemovalModelOptions(opts)
+	return &backgroundModel{p: p, id: id}, nil
+}
+
+type backgroundModel struct {
+	p  *Provider
+	id string
+}
+
+// RemoveBackground implements imagegen.BackgroundRemover. rembg's `model`
+// form field is the request's Net (its internal network); the llama-swap
+// model id only picks the upstream. `om=true` returns the black/white
+// foreground mask instead of the RGBA cutout.
+func (m *backgroundModel) RemoveBackground(ctx context.Context, req imagegen.BackgroundRemovalRequest, opts ...imagegen.BackgroundRemovalOption) (*imagegen.Result, error) {
+	req = req.Apply(opts...)
+	if len(req.Image.Data) == 0 {
+		return nil, fmt.Errorf("%w: background removal requires an image", llm.ErrUnsupported)
+	}
+	path, err := upstreamPath(m.id, "/api/remove")
+	if err != nil {
+		return nil, err
+	}
+	om := ""
+	if req.OnlyMask {
+		om = "true"
+	}
+	body, contentType, err := buildMultipart("build background-removal form",
+		filePart{field: "file", filename: "image.png", data: req.Image.Data},
+		[]formField{
+			{"model", req.Net, false},
+			{"om", om, false},
+		})
+	if err != nil {
+		return nil, err
+	}
+	raw, respType, err := m.p.doRaw(ctx, http.MethodPost, path, m.id, contentType, body, maxResponseBytes)
+	if err != nil {
+		return nil, err
+	}
+	return singleImageResult(m.p.name, m.id, "background removal", raw, respType)
+}
+
+// singleImageResult wraps one raw image body into an imagegen.Result,
+// rejecting empty or non-image payloads (a proxy error page must not become
+// "the image").
+func singleImageResult(provider, model, verb string, raw []byte, contentType string) (*imagegen.Result, error) {
+	if len(raw) == 0 {
+		return nil, &llm.APIError{Provider: provider, Model: model, Message: verb + " response contained no image"}
+	}
+	mimeType := sniffImageMIME(raw)
+	if ct := strings.TrimSpace(contentType); ct != "" && !strings.HasPrefix(ct, "image/") && !strings.HasPrefix(http.DetectContentType(raw), "image/") {
+		return nil, &llm.APIError{Provider: provider, Model: model, Message: fmt.Sprintf("%s response is not an image (Content-Type %q)", verb, ct)}
+	}
+	return &imagegen.Result{Images: []llm.ImagePart{{MIME: mimeType, Data: raw}}}, nil
+}
+
+// --- frame interpolation ---
+
+// InterpolatorModel implements videogen.InterpolationProvider against the
+// mediautils shim's POST /v1/interpolate.
+func (p *Provider) InterpolatorModel(id string, opts ...videogen.InterpolatorModelOption) (videogen.Interpolator, error) {
+	if err := p.requireBaseURL(); err != nil {
+		return nil, err
+	}
+	_ = videogen.ApplyInterpolatorModelOptions(opts)
+	return &interpolatorModel{p: p, id: id}, nil
+}
+
+type interpolatorModel struct {
+	p  *Provider
+	id string
+}
+
+// Interpolate implements videogen.Interpolator. The response body IS the
+// encoded clip (same contract as /v1/videos/sync), hence the video-sized
+// response cap and the same MIME resolution rules.
+func (m *interpolatorModel) Interpolate(ctx context.Context, req videogen.InterpolateRequest, opts ...videogen.InterpolateOption) (*videogen.Result, error) {
+	req = req.Apply(opts...)
+	if len(req.Video.Data) == 0 {
+		return nil, fmt.Errorf("%w: interpolation requires a video", llm.ErrUnsupported)
+	}
+	if req.Multi != 0 && req.Multi != 2 && req.Multi != 4 {
+		return nil, fmt.Errorf("%w: interpolation multi must be 2 or 4, got %d", llm.ErrUnsupported, req.Multi)
+	}
+	if req.TargetFPS < 0 {
+		return nil, fmt.Errorf("%w: target fps must be >= 0, got %d", llm.ErrUnsupported, req.TargetFPS)
+	}
+	path, err := upstreamPath(m.id, "/v1/interpolate")
+	if err != nil {
+		return nil, err
+	}
+	multi := ""
+	if req.Multi != 0 {
+		multi = strconv.Itoa(req.Multi)
+	}
+	mode := ""
+	targetFPS := ""
+	if req.SlowMo {
+		mode = "slowmo"
+	} else if req.TargetFPS > 0 {
+		targetFPS = strconv.Itoa(req.TargetFPS)
+	}
+	body, contentType, err := buildMultipart("build interpolate form",
+		filePart{field: "file", filename: "video.mp4", data: req.Video.Data},
+		[]formField{
+			{"multi", multi, false},
+			{"mode", mode, false},
+			{"target_fps", targetFPS, false},
+		})
+	if err != nil {
+		return nil, err
+	}
+	raw, respType, err := m.p.doRaw(ctx, http.MethodPost, path, m.id, contentType, body, maxVideoResponseBytes)
+	if err != nil {
+		return nil, err
+	}
+	if len(raw) == 0 {
+		return nil, &llm.APIError{Provider: m.p.name, Model: m.id, Message: "interpolate response contained no video"}
+	}
+	mimeType := videoMIME(respType, raw)
+	if mimeType == "" {
+		return nil, &llm.APIError{Provider: m.p.name, Model: m.id, Message: "interpolate response is not a video"}
+	}
+	return &videogen.Result{Video: videogen.Video{Data: raw, MIME: mimeType}}, nil
+}

provider/llamaswap/mediautil_test.go

@@ -0,0 +1,253 @@
+package llamaswap
+
+import (
+	"context"
+	"encoding/base64"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"gitea.stevedudenhoeffer.com/steve/majordomo/imagegen"
+	"gitea.stevedudenhoeffer.com/steve/majordomo/llm"
+	"gitea.stevedudenhoeffer.com/steve/majordomo/videogen"
+)
+
+func pngFixture(t *testing.T) []byte {
+	t.Helper()
+	raw, err := base64.StdEncoding.DecodeString(onePixelPNG)
+	if err != nil {
+		t.Fatalf("decode fixture: %v", err)
+	}
+	return raw
+}
+
+func TestUpscale(t *testing.T) {
+	png := pngFixture(t)
+	var gotPath, gotScale, gotFilename string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotPath = r.URL.Path
+		if err := r.ParseMultipartForm(1 << 20); err != nil {
+			t.Errorf("parse multipart: %v", err)
+		}
+		gotScale = r.FormValue("scale")
+		if f, hdr, err := r.FormFile("file"); err == nil {
+			gotFilename = hdr.Filename
+			f.Close()
+		} else {
+			t.Errorf("file part: %v", err)
+		}
+		w.Header().Set("Content-Type", "image/png")
+		_, _ = w.Write(png)
+	}))
+	defer srv.Close()
+
+	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
+	up, err := p.UpscaleModel("mediautils")
+	if err != nil {
+		t.Fatalf("UpscaleModel: %v", err)
+	}
+	res, err := up.Upscale(context.Background(),
+		imagegen.UpscaleRequest{Image: imagegen.Image{MIME: "image/png", Data: png}},
+		imagegen.WithUpscaleScale(2))
+	if err != nil {
+		t.Fatalf("Upscale: %v", err)
+	}
+	if gotPath != "/upstream/mediautils/v1/upscale" {
+		t.Errorf("path = %q", gotPath)
+	}
+	if gotScale != "2" || gotFilename != "image.png" {
+		t.Errorf("scale/filename = %q/%q", gotScale, gotFilename)
+	}
+	if len(res.Images) != 1 || res.Images[0].MIME != "image/png" {
+		t.Fatalf("images = %+v", res.Images)
+	}
+}
+
+func TestUpscaleRejectsBadArgs(t *testing.T) {
+	p := New(WithBaseURL("http://unused"))
+	up, _ := p.UpscaleModel("mediautils")
+	if _, err := up.Upscale(context.Background(), imagegen.UpscaleRequest{}); !errors.Is(err, llm.ErrUnsupported) {
+		t.Errorf("no image: err = %v, want ErrUnsupported", err)
+	}
+	if _, err := up.Upscale(context.Background(),
+		imagegen.UpscaleRequest{Image: imagegen.Image{Data: []byte{1}}, Scale: 3}); !errors.Is(err, llm.ErrUnsupported) {
+		t.Errorf("scale 3: err = %v, want ErrUnsupported", err)
+	}
+}
+
+func TestUpscaleRejectsNonImageResponse(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/html")
+		_, _ = w.Write([]byte("<html>proxy error page</html>"))
+	}))
+	defer srv.Close()
+
+	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
+	up, _ := p.UpscaleModel("mediautils")
+	_, err := up.Upscale(context.Background(),
+		imagegen.UpscaleRequest{Image: imagegen.Image{Data: pngFixture(t)}})
+	var apiErr *llm.APIError
+	if !errors.As(err, &apiErr) {
+		t.Fatalf("err = %v, want APIError for non-image body", err)
+	}
+}
+
+func TestRemoveBackground(t *testing.T) {
+	png := pngFixture(t)
+	var gotPath, gotNet, gotOM string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotPath = r.URL.Path
+		if err := r.ParseMultipartForm(1 << 20); err != nil {
+			t.Errorf("parse multipart: %v", err)
+		}
+		gotNet = r.FormValue("model")
+		gotOM = r.FormValue("om")
+		w.Header().Set("Content-Type", "image/png")
+		_, _ = w.Write(png)
+	}))
+	defer srv.Close()
+
+	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
+	br, err := p.BackgroundRemovalModel("rembg")
+	if err != nil {
+		t.Fatalf("BackgroundRemovalModel: %v", err)
+	}
+	res, err := br.RemoveBackground(context.Background(),
+		imagegen.BackgroundRemovalRequest{Image: imagegen.Image{Data: png}},
+		imagegen.WithBackgroundNet("birefnet-general"), imagegen.WithOnlyMask())
+	if err != nil {
+		t.Fatalf("RemoveBackground: %v", err)
+	}
+	if gotPath != "/upstream/rembg/api/remove" {
+		t.Errorf("path = %q", gotPath)
+	}
+	if gotNet != "birefnet-general" || gotOM != "true" {
+		t.Errorf("net/om = %q/%q", gotNet, gotOM)
+	}
+	if len(res.Images) != 1 {
+		t.Fatalf("images = %+v", res.Images)
+	}
+}
+
+func TestRemoveBackgroundOmitsUnsetFields(t *testing.T) {
+	png := pngFixture(t)
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if err := r.ParseMultipartForm(1 << 20); err != nil {
+			t.Errorf("parse multipart: %v", err)
+		}
+		if _, ok := r.MultipartForm.Value["model"]; ok {
+			t.Error("model field sent for default net; want omitted")
+		}
+		if _, ok := r.MultipartForm.Value["om"]; ok {
+			t.Error("om field sent for cutout mode; want omitted")
+		}
+		w.Header().Set("Content-Type", "image/png")
+		_, _ = w.Write(png)
+	}))
+	defer srv.Close()
+
+	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
+	br, _ := p.BackgroundRemovalModel("rembg")
+	if _, err := br.RemoveBackground(context.Background(),
+		imagegen.BackgroundRemovalRequest{Image: imagegen.Image{Data: png}}); err != nil {
+		t.Fatalf("RemoveBackground: %v", err)
+	}
+}
+
+// mp4Fixture is a minimal ftyp box so http.DetectContentType sniffs video/mp4.
+func mp4Fixture() []byte {
+	return []byte{0, 0, 0, 24, 'f', 't', 'y', 'p', 'i', 's', 'o', 'm',
+		0, 0, 2, 0, 'i', 's', 'o', 'm', 'i', 's', 'o', '2'}
+}
+
+func TestInterpolate(t *testing.T) {
+	var gotPath, gotMulti, gotMode, gotTargetFPS string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotPath = r.URL.Path
+		if err := r.ParseMultipartForm(1 << 20); err != nil {
+			t.Errorf("parse multipart: %v", err)
+		}
+		gotMulti = r.FormValue("multi")
+		gotMode = r.FormValue("mode")
+		gotTargetFPS = r.FormValue("target_fps")
+		w.Header().Set("Content-Type", "video/mp4")
+		_, _ = w.Write(mp4Fixture())
+	}))
+	defer srv.Close()
+
+	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
+	ip, err := p.InterpolatorModel("mediautils")
+	if err != nil {
+		t.Fatalf("InterpolatorModel: %v", err)
+	}
+	res, err := ip.Interpolate(context.Background(),
+		videogen.InterpolateRequest{Video: videogen.Video{Data: mp4Fixture(), MIME: "video/mp4"}},
+		videogen.WithInterpolateMulti(2), videogen.WithTargetFPS(60))
+	if err != nil {
+		t.Fatalf("Interpolate: %v", err)
+	}
+	if gotPath != "/upstream/mediautils/v1/interpolate" {
+		t.Errorf("path = %q", gotPath)
+	}
+	if gotMulti != "2" || gotMode != "" || gotTargetFPS != "60" {
+		t.Errorf("multi/mode/target_fps = %q/%q/%q", gotMulti, gotMode, gotTargetFPS)
+	}
+	if res.Video.MIME != "video/mp4" || len(res.Video.Data) == 0 {
+		t.Fatalf("video = %q/%d bytes", res.Video.MIME, len(res.Video.Data))
+	}
+}
+
+func TestInterpolateSlowMoSetsModeAndDropsTargetFPS(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if err := r.ParseMultipartForm(1 << 20); err != nil {
+			t.Errorf("parse multipart: %v", err)
+		}
+		if got := r.FormValue("mode"); got != "slowmo" {
+			t.Errorf("mode = %q, want slowmo", got)
+		}
+		if _, ok := r.MultipartForm.Value["target_fps"]; ok {
+			t.Error("target_fps sent in slowmo mode; want omitted")
+		}
+		w.Header().Set("Content-Type", "video/mp4")
+		_, _ = w.Write(mp4Fixture())
+	}))
+	defer srv.Close()
+
+	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
+	ip, _ := p.InterpolatorModel("mediautils")
+	_, err := ip.Interpolate(context.Background(),
+		videogen.InterpolateRequest{Video: videogen.Video{Data: mp4Fixture()}, TargetFPS: 60},
+		videogen.WithSlowMo())
+	if err != nil {
+		t.Fatalf("Interpolate: %v", err)
+	}
+}
+
+func TestInterpolateRejectsBadArgs(t *testing.T) {
+	p := New(WithBaseURL("http://unused"))
+	ip, _ := p.InterpolatorModel("mediautils")
+	if _, err := ip.Interpolate(context.Background(), videogen.InterpolateRequest{}); !errors.Is(err, llm.ErrUnsupported) {
+		t.Errorf("no video: err = %v, want ErrUnsupported", err)
+	}
+	if _, err := ip.Interpolate(context.Background(),
+		videogen.InterpolateRequest{Video: videogen.Video{Data: []byte{1}}, Multi: 3}); !errors.Is(err, llm.ErrUnsupported) {
+		t.Errorf("multi 3: err = %v, want ErrUnsupported", err)
+	}
+}
+
+func TestUpstreamPathRejectsSeparators(t *testing.T) {
+	for _, bad := range []string{"", "a/b", "a?b", "a#b"} {
+		if _, err := upstreamPath(bad, "/x"); err == nil {
+			t.Errorf("upstreamPath(%q) succeeded; want error", bad)
+		}
+	}
+	got, err := upstreamPath("rembg", "api/remove")
+	if err != nil || got != "/upstream/rembg/api/remove" {
+		t.Errorf("upstreamPath = %q, %v", got, err)
+	}
+	if !strings.HasPrefix(got, "/upstream/") {
+		t.Errorf("path prefix wrong: %q", got)
+	}
+}

provider/llamaswap/mesh.go

@@ -0,0 +1,128 @@
+// mesh.go implements meshgen.Provider against a Hunyuan3D-2.1-style
+// api_server reached through llama-swap's /upstream passthrough (ADR-0020):
+//
+//	POST /upstream/<id>/generate   JSON {image: <b64>, type: "glb"|"stl"|...}
+//
+// The response body IS the encoded mesh (binary, Content-Type
+// application/octet-stream), so one request yields exactly one asset.
+package llamaswap
+
+import (
+	"bytes"
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+
+	"gitea.stevedudenhoeffer.com/steve/majordomo/llm"
+	"gitea.stevedudenhoeffer.com/steve/majordomo/meshgen"
+)
+
+// maxMeshResponseBytes caps the /generate body — a high-resolution textured
+// mesh legitimately passes the 64MB JSON cap, but stays far under video
+// scale.
+const maxMeshResponseBytes = 256 << 20
+
+// MeshModel implements meshgen.Provider. The id selects which upstream
+// llama-swap loads.
+func (p *Provider) MeshModel(id string, opts ...meshgen.ModelOption) (meshgen.Model, error) {
+	if err := p.requireBaseURL(); err != nil {
+		return nil, err
+	}
+	_ = meshgen.ApplyModelOptions(opts)
+	return &meshModel{p: p, id: id}, nil
+}
+
+type meshModel struct {
+	p  *Provider
+	id string
+}
+
+// hunyuanGenerateRequest is the Hunyuan3D api_server /generate shape.
+// Optional fields are pointers/omitempty so unset values fall back to the
+// server's defaults (mirrors the sd-server wire structs).
+type hunyuanGenerateRequest struct {
+	Image             string   `json:"image"`
+	Type              string   `json:"type,omitempty"`
+	Texture           bool     `json:"texture"`
+	RemoveBackground  *bool    `json:"remove_background,omitempty"`
+	OctreeResolution  int      `json:"octree_resolution,omitempty"`
+	NumInferenceSteps *int     `json:"num_inference_steps,omitempty"`
+	GuidanceScale     *float64 `json:"guidance_scale,omitempty"`
+	Seed              *int64   `json:"seed,omitempty"`
+	FaceCount         int      `json:"face_count,omitempty"`
+}
+
+// meshFormats maps the supported output containers to MIME types.
+var meshFormats = map[string]string{
+	"glb": "model/gltf-binary",
+	"stl": "model/stl",
+	"obj": "model/obj",
+}
+
+// Generate implements meshgen.Model.
+func (m *meshModel) Generate(ctx context.Context, req meshgen.Request, opts ...meshgen.Option) (*meshgen.Result, error) {
+	req = req.Apply(opts...)
+	if len(req.Image.Data) == 0 {
+		return nil, fmt.Errorf("%w: mesh generation requires an image", llm.ErrUnsupported)
+	}
+	format := strings.ToLower(strings.TrimSpace(req.Format))
+	if format == "" {
+		format = "glb"
+	}
+	mimeType, ok := meshFormats[format]
+	if !ok {
+		return nil, fmt.Errorf("%w: unsupported mesh format %q (want glb, stl, or obj)", llm.ErrUnsupported, req.Format)
+	}
+	if req.OctreeResolution < 0 || req.FaceCount < 0 {
+		return nil, fmt.Errorf("%w: octree resolution and face count must be >= 0", llm.ErrUnsupported)
+	}
+
+	path, err := upstreamPath(m.id, "/generate")
+	if err != nil {
+		return nil, err
+	}
+	wire := hunyuanGenerateRequest{
+		Image:             base64.StdEncoding.EncodeToString(req.Image.Data),
+		Type:              format,
+		Texture:           req.Texture,
+		RemoveBackground:  req.RemoveBackground,
+		OctreeResolution:  req.OctreeResolution,
+		NumInferenceSteps: req.Steps,
+		GuidanceScale:     req.GuidanceScale,
+		Seed:              req.Seed,
+		FaceCount:         req.FaceCount,
+	}
+
+	// doRaw + manual JSON encode (not doJSON): the SUCCESS body is binary
+	// mesh bytes, not JSON.
+	encoded, err := json.Marshal(wire)
+	if err != nil {
+		return nil, fmt.Errorf("llama-swap: encode mesh request: %w", err)
+	}
+	raw, _, err := m.p.doRaw(ctx, http.MethodPost, path, m.id, "application/json", bytes.NewReader(encoded), maxMeshResponseBytes)
+	if err != nil {
+		return nil, err
+	}
+	if len(raw) == 0 {
+		return nil, &llm.APIError{Provider: m.p.name, Model: m.id, Message: "mesh response contained no data"}
+	}
+	// A JSON body on the success path is the server reporting a soft error
+	// (or an API drift) — never hand it back as "the mesh".
+	if first := strings.TrimLeft(string(raw[:min(len(raw), 64)]), " \t\r\n"); strings.HasPrefix(first, "{") || strings.HasPrefix(first, "[") {
+		return nil, &llm.APIError{Provider: m.p.name, Model: m.id,
+			Message: "mesh response is JSON, not mesh bytes: " + truncateForError(raw)}
+	}
+	return &meshgen.Result{Mesh: meshgen.Mesh{Data: raw, Format: format, MIME: mimeType}}, nil
+}
+
+// truncateForError bounds a payload quoted into an error message.
+func truncateForError(b []byte) string {
+	const cap = 500
+	if len(b) > cap {
+		return string(b[:cap]) + "..."
+	}
+	return string(b)
+}

provider/llamaswap/mesh_diarize_test.go

@@ -0,0 +1,170 @@
+package llamaswap
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"gitea.stevedudenhoeffer.com/steve/majordomo/audio"
+	"gitea.stevedudenhoeffer.com/steve/majordomo/llm"
+	"gitea.stevedudenhoeffer.com/steve/majordomo/meshgen"
+)
+
+func TestMeshGenerate(t *testing.T) {
+	png := pngFixture(t)
+	stl := []byte("solid mort\nendsolid mort\n")
+	var gotPath string
+	var gotBody map[string]any
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotPath = r.URL.Path
+		_ = json.NewDecoder(r.Body).Decode(&gotBody)
+		w.Header().Set("Content-Type", "application/octet-stream")
+		_, _ = w.Write(stl)
+	}))
+	defer srv.Close()
+
+	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
+	mm, err := p.MeshModel("image3d-hunyuan21")
+	if err != nil {
+		t.Fatalf("MeshModel: %v", err)
+	}
+	res, err := mm.Generate(context.Background(),
+		meshgen.Request{Image: meshgen.Image{MIME: "image/png", Data: png}},
+		meshgen.WithFormat("stl"), meshgen.WithSeed(7))
+	if err != nil {
+		t.Fatalf("Generate: %v", err)
+	}
+	if gotPath != "/upstream/image3d-hunyuan21/generate" {
+		t.Errorf("path = %q", gotPath)
+	}
+	if gotBody["type"] != "stl" || gotBody["image"] != base64.StdEncoding.EncodeToString(png) {
+		t.Errorf("type/image = %v/(b64 mismatch)", gotBody["type"])
+	}
+	if gotBody["seed"] != float64(7) {
+		t.Errorf("seed = %v", gotBody["seed"])
+	}
+	if _, ok := gotBody["octree_resolution"]; ok {
+		t.Error("octree_resolution sent when unset; want omitted")
+	}
+	if res.Mesh.Format != "stl" || res.Mesh.MIME != "model/stl" || string(res.Mesh.Data) != string(stl) {
+		t.Fatalf("mesh = %+v", res.Mesh)
+	}
+}
+
+func TestMeshGenerateRejectsJSONBody(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/octet-stream")
+		_, _ = w.Write([]byte(`  {"detail": "queue full"}`))
+	}))
+	defer srv.Close()
+
+	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
+	mm, _ := p.MeshModel("image3d-hunyuan21")
+	_, err := mm.Generate(context.Background(),
+		meshgen.Request{Image: meshgen.Image{Data: pngFixture(t)}})
+	var apiErr *llm.APIError
+	if !errors.As(err, &apiErr) {
+		t.Fatalf("err = %v, want APIError for JSON success body", err)
+	}
+}
+
+func TestMeshGenerateRejectsBadArgs(t *testing.T) {
+	p := New(WithBaseURL("http://unused"))
+	mm, _ := p.MeshModel("image3d-hunyuan21")
+	if _, err := mm.Generate(context.Background(), meshgen.Request{}); !errors.Is(err, llm.ErrUnsupported) {
+		t.Errorf("no image: err = %v, want ErrUnsupported", err)
+	}
+	if _, err := mm.Generate(context.Background(),
+		meshgen.Request{Image: meshgen.Image{Data: []byte{1}}, Format: "fbx"}); !errors.Is(err, llm.ErrUnsupported) {
+		t.Errorf("format fbx: err = %v, want ErrUnsupported", err)
+	}
+}
+
+func TestDiarize(t *testing.T) {
+	var gotPath string
+	var gotQuery map[string][]string
+	var gotField string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotPath = r.URL.Path
+		gotQuery = r.URL.Query()
+		if err := r.ParseMultipartForm(1 << 20); err != nil {
+			t.Errorf("parse multipart: %v", err)
+		}
+		if f, _, err := r.FormFile("audio_file"); err == nil {
+			gotField = "audio_file"
+			f.Close()
+		}
+		_, _ = w.Write([]byte(`{
+			"text": "hello there. general kenobi.",
+			"language": "en",
+			"segments": [
+				{"start": 0.0, "end": 1.2, "text": "hello there.", "speaker": "SPEAKER_00"},
+				{"start": 1.4, "end": 3.0, "text": "general kenobi.", "speaker": "SPEAKER_01"}
+			]
+		}`))
+	}))
+	defer srv.Close()
+
+	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
+	dm, err := p.DiarizationModel("whisperx-diarize")
+	if err != nil {
+		t.Fatalf("DiarizationModel: %v", err)
+	}
+	res, err := dm.Diarize(context.Background(),
+		audio.DiarizationRequest{Audio: []byte("RIFFfake"), MIME: "audio/wav"},
+		audio.WithSpeakerBounds(2, 4), audio.WithDiarizationLanguage("en"))
+	if err != nil {
+		t.Fatalf("Diarize: %v", err)
+	}
+	if gotPath != "/upstream/whisperx-diarize/asr" {
+		t.Errorf("path = %q", gotPath)
+	}
+	for k, want := range map[string]string{
+		"output": "json", "diarize": "true",
+		"min_speakers": "2", "max_speakers": "4", "language": "en",
+	} {
+		if got := gotQuery[k]; len(got) != 1 || got[0] != want {
+			t.Errorf("query %s = %v, want %q", k, got, want)
+		}
+	}
+	if gotField != "audio_file" {
+		t.Error("audio_file part missing")
+	}
+	if len(res.Segments) != 2 || res.Segments[1].Speaker != "SPEAKER_01" {
+		t.Fatalf("segments = %+v", res.Segments)
+	}
+	if res.Language != "en" || res.Text == "" {
+		t.Errorf("language/text = %q/%q", res.Language, res.Text)
+	}
+}
+
+func TestDiarizeRejectsBadArgs(t *testing.T) {
+	p := New(WithBaseURL("http://unused"))
+	dm, _ := p.DiarizationModel("whisperx-diarize")
+	if _, err := dm.Diarize(context.Background(), audio.DiarizationRequest{}); !errors.Is(err, llm.ErrUnsupported) {
+		t.Errorf("no audio: err = %v, want ErrUnsupported", err)
+	}
+	if _, err := dm.Diarize(context.Background(),
+		audio.DiarizationRequest{Audio: []byte{1}, MinSpeakers: 5, MaxSpeakers: 2}); !errors.Is(err, llm.ErrUnsupported) {
+		t.Errorf("bounds 5>2: err = %v, want ErrUnsupported", err)
+	}
+}
+
+func TestDiarizeEmptyTranscriptIsError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write([]byte(`{"text": "", "segments": []}`))
+	}))
+	defer srv.Close()
+
+	p := New(WithBaseURL(srv.URL), WithHTTPClient(srv.Client()))
+	dm, _ := p.DiarizationModel("whisperx-diarize")
+	_, err := dm.Diarize(context.Background(), audio.DiarizationRequest{Audio: []byte{1}})
+	var apiErr *llm.APIError
+	if !errors.As(err, &apiErr) {
+		t.Fatalf("err = %v, want APIError for empty transcript", err)
+	}
+}

provider/llamaswap/upstream.go

@@ -0,0 +1,61 @@
+package llamaswap
+
+import (
+	"bytes"
+	"fmt"
+	"mime/multipart"
+	"strings"
+)
+
+// upstreamPath builds a path through llama-swap's generic /upstream/<model>/
+// passthrough, which pins the model (triggering the normal load/swap queue)
+// and forwards the remaining path to the upstream verbatim. This is how the
+// provider reaches upstreams whose native APIs carry no routable `model`
+// field (rembg, mediautils, WhisperX, ACE-Step, ...) without needing a
+// llama-swap route per endpoint (ADR-0020).
+//
+// Why reject rather than escape: same rationale as Unload — model ids
+// legitimately contain ":" but never path-structure characters, and escaping
+// would mask a config error instead of surfacing it.
+func upstreamPath(model, rest string) (string, error) {
+	if strings.TrimSpace(model) == "" {
+		return "", fmt.Errorf("llama-swap: upstream call requires a model id")
+	}
+	if strings.ContainsAny(model, "/?#") {
+		return "", fmt.Errorf("llama-swap: invalid model id %q for upstream call (contains a path separator)", model)
+	}
+	if !strings.HasPrefix(rest, "/") {
+		rest = "/" + rest
+	}
+	return "/upstream/" + model + rest, nil
+}
+
+// filePart is the single file entry of a media multipart form.
+type filePart struct {
+	field    string // form field name ("file", "audio_file", ...)
+	filename string // already sanitized
+	data     []byte
+}
+
+// buildMultipart assembles a one-file multipart body: the file part first,
+// then the given fields (optional fields skipped when empty, matching
+// writeFormFields). wrap labels errors. Returns the body and its content
+// type.
+func buildMultipart(wrap string, file filePart, fields []formField) (*bytes.Buffer, string, error) {
+	var buf bytes.Buffer
+	w := multipart.NewWriter(&buf)
+	fw, err := w.CreateFormFile(file.field, file.filename)
+	if err != nil {
+		return nil, "", fmt.Errorf("llama-swap: %s: %w", wrap, err)
+	}
+	if _, err := fw.Write(file.data); err != nil {
+		return nil, "", fmt.Errorf("llama-swap: %s: %w", wrap, err)
+	}
+	if err := writeFormFields(w, wrap, fields); err != nil {
+		return nil, "", err
+	}
+	if err := w.Close(); err != nil {
+		return nil, "", fmt.Errorf("llama-swap: %s: %w", wrap, err)
+	}
+	return &buf, w.FormDataContentType(), nil
+}

videogen/interpolate.go

@@ -0,0 +1,82 @@
+package videogen
+
+import "context"
+
+// InterpolateRequest asks a frame-interpolation backend (RIFE-style) to
+// synthesize intermediate frames in an existing clip. Zero values mean
+// "backend default" (ADR-0020).
+type InterpolateRequest struct {
+	// Video is the clip to interpolate. Required.
+	Video Video
+
+	// Multi is the frame multiplier (2 or 4 on the reference backend);
+	// 0 = backend default (2).
+	Multi int
+
+	// SlowMo plays the synthesized frames at the SOURCE frame rate instead of
+	// multiplying it: Multi-times slow motion. The backend strips audio in
+	// this mode (time-stretched audio is noise).
+	SlowMo bool
+
+	// TargetFPS resamples the smoothed clip to a specific frame rate
+	// (e.g. 60); 0 = Multi times the source rate. Ignored in SlowMo mode.
+	TargetFPS int
+}
+
+// InterpolateOption mutates an InterpolateRequest before it is sent.
+type InterpolateOption func(*InterpolateRequest)
+
+// WithInterpolateMulti sets the frame multiplier.
+func WithInterpolateMulti(m int) InterpolateOption {
+	return func(r *InterpolateRequest) { r.Multi = m }
+}
+
+// WithSlowMo switches to slow-motion output.
+func WithSlowMo() InterpolateOption { return func(r *InterpolateRequest) { r.SlowMo = true } }
+
+// WithTargetFPS resamples the smoothed clip to a specific frame rate.
+func WithTargetFPS(fps int) InterpolateOption {
+	return func(r *InterpolateRequest) { r.TargetFPS = fps }
+}
+
+// Apply returns a copy of the request with all options applied.
+func (r InterpolateRequest) Apply(opts ...InterpolateOption) InterpolateRequest {
+	for _, opt := range opts {
+		opt(&r)
+	}
+	return r
+}
+
+// Interpolator synthesizes intermediate frames (fps boost or slow-mo). Its
+// own small interface rather than a method on Model: interpolators are not
+// generators — they bind to a different backend id entirely.
+type Interpolator interface {
+	// Interpolate returns the smoothed (or slowed) clip.
+	Interpolate(ctx context.Context, req InterpolateRequest, opts ...InterpolateOption) (*Result, error)
+}
+
+// InterpolatorModelOption configures an Interpolator at construction time.
+// Reserved for future per-model settings.
+type InterpolatorModelOption func(*InterpolatorModelConfig)
+
+// InterpolatorModelConfig carries per-model construction settings.
+type InterpolatorModelConfig struct{}
+
+// ApplyInterpolatorModelOptions folds options into a config.
+func ApplyInterpolatorModelOptions(opts []InterpolatorModelOption) InterpolatorModelConfig {
+	var cfg InterpolatorModelConfig
+	for _, opt := range opts {
+		opt(&cfg)
+	}
+	return cfg
+}
+
+// InterpolationProvider mints Interpolators bound to one backend.
+type InterpolationProvider interface {
+	// Name is the registry identifier for the provider.
+	Name() string
+
+	// InterpolatorModel returns an Interpolator bound to the given id (passed
+	// through to the backend verbatim; no catalog validation).
+	InterpolatorModel(id string, opts ...InterpolatorModelOption) (Interpolator, error)
+}