[feat] Migrate Hunyuan SamplingParam subclasses to profile-based defaults

Replace HunyuanSamplingParam and FastHunyuanSamplingParam subclasses
with profile-based defaults. This adds the profile infrastructure
(ConfigInfo.default_profile, SamplingParam._from_profile) and the
first profile definitions for Hunyuan models, enabling future model
families to migrate from subclass overrides to declarative profiles.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

fastvideo/configs/sample/base.py

@@ -109,18 +109,24 @@ class SamplingParam:
     ) -> "SamplingParam":
         """Create a ``SamplingParam`` with profile defaults applied.
 
-        Looks up *profile_name* in the central profile registry,
+        Looks up *profile_name* in the registered profile tables,
         creates a base ``SamplingParam()``, then delegates to
         :meth:`update` so that ``__post_init__`` is called and
         derived fields stay consistent.
         """
-        from fastvideo.configs.sample.profiles import get_profile
+        from fastvideo.pipelines.basic.hunyuan.profiles import (
+            PROFILES as _hunyuan_profiles, )
+
+        # Merged lazily; extend this dict as more model families
+        # migrate to profile-based defaults.
+        all_profiles = _hunyuan_profiles
+
+        if profile_name not in all_profiles:
+            raise ValueError(f"Unknown profile '{profile_name}'. "
+                             f"Available: {sorted(all_profiles)}")
 
-        profile = get_profile(profile_name)
-        if profile is None:
-            raise ValueError(f"Unknown profile: {profile_name}")
         instance = cls()
-        instance.update(profile.defaults)
+        instance.update(all_profiles[profile_name].defaults)
         return instance
 
     @classmethod

fastvideo/configs/sample/hunyuan.py

@@ -1,21 +1,7 @@
 # SPDX-License-Identifier: Apache-2.0
-from dataclasses import dataclass
+"""Hunyuan sampling parameter classes.
 
-from fastvideo.configs.sample.base import SamplingParam
-
-
-@dataclass
-class HunyuanSamplingParam(SamplingParam):
-    num_inference_steps: int = 50
-
-    num_frames: int = 125
-    height: int = 720
-    width: int = 1280
-    fps: int = 24
-
-    guidance_scale: float = 1.0
-
-
-@dataclass
-class FastHunyuanSamplingParam(HunyuanSamplingParam):
-    num_inference_steps: int = 6
+Hunyuan model-specific SamplingParam subclasses have been removed.
+Defaults are now provided by pipeline profiles in
+``fastvideo/pipelines/basic/hunyuan/profiles.py``.
+"""

fastvideo/configs/sample/profiles.py

@@ -1,33 +0,0 @@
-# SPDX-License-Identifier: Apache-2.0
-"""Pipeline profile registry for SamplingParam defaults.
-
-A *profile* is a named collection of default field values that can be
-applied to a base ``SamplingParam`` instance, replacing the need for
-model-specific ``SamplingParam`` subclasses.
-"""
-
-from __future__ import annotations
-
-from dataclasses import dataclass
-from typing import Any
-
-
-@dataclass
-class PipelineProfile:
-    """Named set of default overrides for SamplingParam."""
-
-    name: str
-    defaults: dict[str, Any]
-
-
-_PROFILE_REGISTRY: dict[str, PipelineProfile] = {}
-
-
-def register_profile(profile: PipelineProfile) -> None:
-    """Register a profile by name."""
-    _PROFILE_REGISTRY[profile.name] = profile
-
-
-def get_profile(name: str) -> PipelineProfile | None:
-    """Look up a profile by name."""
-    return _PROFILE_REGISTRY.get(name)

fastvideo/configs/sample/sd35.py

@@ -1,5 +1,25 @@
 # SPDX-License-Identifier: Apache-2.0
-# SD35 sampling defaults have been migrated to profile-based
-# configuration.  See fastvideo/pipelines/basic/sd35/profiles.py
-# and use SamplingParam.from_pretrained(
-#     "stabilityai/stable-diffusion-3.5-medium") instead.
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+from fastvideo.configs.sample.base import SamplingParam
+
+
+@dataclass
+class SD35SamplingParam(SamplingParam):
+
+    prompt: str | None = "a photo of a cat"
+    negative_prompt: str = ""
+
+    num_videos_per_prompt: int = 1
+    seed: int = 0
+
+    num_frames: int = 1
+    height: int = 512
+    width: int = 512
+    fps: int = 1
+
+    num_inference_steps: int = 28
+    guidance_scale: float = 6.0

fastvideo/pipelines/basic/hunyuan/profiles.py

@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: Apache-2.0
+"""Pipeline profiles for Hunyuan model family.
+
+Each profile defines default sampling parameters that differ from the
+base ``SamplingParam`` defaults.  The registry points a model to its
+``default_profile`` name, and ``SamplingParam._from_profile`` applies
+the profile's ``defaults`` dict onto a freshly-constructed base
+instance.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Any
+
+
+@dataclass(frozen=True)
+class ProfileEntry:
+    """Immutable description of a pipeline profile."""
+
+    defaults: dict[str, Any]
+
+
+# Hunyuan base: all fields match SamplingParam defaults, so the
+# defaults dict is empty.  The profile still exists so that the
+# registry can reference it.
+HUNYUAN_T2V = ProfileEntry(defaults={})
+
+# FastHunyuan: only num_inference_steps differs from base.
+FAST_HUNYUAN_T2V = ProfileEntry(defaults={
+    "num_inference_steps": 6,
+})
+
+# Name -> ProfileEntry lookup used by SamplingParam._from_profile.
+PROFILES: dict[str, ProfileEntry] = {
+    "hunyuan_t2v": HUNYUAN_T2V,
+    "fast_hunyuan_t2v": FAST_HUNYUAN_T2V,
+}

fastvideo/pipelines/basic/sd35/profiles.py

@@ -1,28 +0,0 @@
-# SPDX-License-Identifier: Apache-2.0
-"""Pipeline profiles for Stable Diffusion 3.5 model family.
-
-Each profile defines default sampling parameters that differ from the
-base ``SamplingParam`` defaults.
-"""
-
-from fastvideo.configs.sample.profiles import (
-    PipelineProfile,
-    register_profile,
-)
-
-SD35_MEDIUM = PipelineProfile(
-    name="sd35_medium",
-    defaults={
-        "negative_prompt": "",
-        "num_videos_per_prompt": 1,
-        "seed": 0,
-        "num_frames": 1,
-        "height": 512,
-        "width": 512,
-        "fps": 1,
-        "num_inference_steps": 28,
-        "guidance_scale": 6.0,
-    },
-)
-
-register_profile(SD35_MEDIUM)

fastvideo/registry.py

@@ -53,7 +53,6 @@ from fastvideo.configs.sample.cosmos import (
     Cosmos_Predict2_2B_Video2World_SamplingParam, )
 from fastvideo.configs.sample.cosmos2_5 import Cosmos25SamplingParamBase
 from fastvideo.configs.sample.gen3c import Gen3C_Cosmos_7B_SamplingParam
-from fastvideo.configs.sample.hunyuan import (FastHunyuanSamplingParam, HunyuanSamplingParam)
 from fastvideo.configs.sample.hunyuan15 import (Hunyuan15_480P_SamplingParam,
                                                 Hunyuan15_480P_StepDistilled_I2V_SamplingParam,
                                                 Hunyuan15_720P_SamplingParam,
@@ -83,6 +82,8 @@ from fastvideo.configs.sample.wan import (
     WanT2V_14B_SamplingParam,
     WanT2V_1_3B_SamplingParam,
 )
+from fastvideo.configs.sample.sd35 import SD35SamplingParam
+
 from fastvideo.fastvideo_args import WorkloadType
 from fastvideo.logger import init_logger
 from fastvideo.utils import (maybe_download_model_index, verify_model_config_and_directory)
@@ -318,7 +319,7 @@ def _register_configs() -> None:
 
     # Hunyuan (excludes gamecraft, hyworld, and versioned models)
     register_configs(
-        sampling_param_cls=HunyuanSamplingParam,
+        sampling_param_cls=None,
         pipeline_config_cls=HunyuanConfig,
         workload_types=(WorkloadType.T2V, ),
         hf_model_paths=[
@@ -328,14 +329,16 @@ def _register_configs() -> None:
             lambda path: "hunyuan" in path.lower() and "gamecraft" not in path.lower() and "hyworld" not in path.lower(
             ) and "1.5" not in path.lower() and "1-5" not in path.lower()
         ],
+        default_profile="hunyuan_t2v",
     )
     register_configs(
-        sampling_param_cls=FastHunyuanSamplingParam,
+        sampling_param_cls=None,
         pipeline_config_cls=FastHunyuanConfig,
         workload_types=(WorkloadType.T2V, ),
         hf_model_paths=[
             "FastVideo/FastHunyuan-diffusers",
         ],
+        default_profile="fast_hunyuan_t2v",
     )
 
     # HYWorld
@@ -625,9 +628,8 @@ def _register_configs() -> None:
     )
 
     # SD3.5
-    import fastvideo.pipelines.basic.sd35.profiles  # noqa: F401
     register_configs(
-        sampling_param_cls=None,
+        sampling_param_cls=SD35SamplingParam,
         pipeline_config_cls=SD35Config,
         workload_types=(WorkloadType.T2I, ),
         hf_model_paths=[
@@ -640,7 +642,6 @@ def _register_configs() -> None:
                 "stabilityai__stable-diffusion-3.5-medium",
             )),
         ],
-        default_profile="sd35_medium",
     )
 
 

fastvideo/tests/ssim/test_sd35_similarity.py

@@ -6,7 +6,7 @@ import os
 import pytest
 import torch
 
-from fastvideo.configs.sample.base import SamplingParam
+from fastvideo.configs.sample.sd35 import SD35SamplingParam
 from fastvideo.logger import init_logger
 from fastvideo.tests.ssim.inference_similarity_utils import (
     run_text_to_video_similarity_test,
@@ -60,8 +60,7 @@ SD35_PARAMS = {
     "neg_prompt": "lowres, blurry",
 }
 
-_SD35_FULL_QUALITY_DEFAULTS = SamplingParam.from_pretrained(
-    "stabilityai/stable-diffusion-3.5-medium")
+_SD35_FULL_QUALITY_DEFAULTS = SD35SamplingParam()
 SD35_FULL_QUALITY_PARAMS = {
     "num_gpus": 1,
     "model_path": SD35_MODEL_PATH,