Ethanfel
bb07bc8169
- Wrap _spectral_metrics + _save_spectrogram in try-except so a matplotlib or STFT error doesn't abort the checkpoint save (matches LoRA trainer) - Remove unused `import math` and `_pil_to_tensor` import - Drop dead `img` variable (_save_spectrogram returns None) Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
372 lines
15 KiB
Python
372 lines
15 KiB
Python
"""SelVA Textual Inversion Trainer.
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Learns K token embedding vectors in CLIP space that guide the base model
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to generate audio in the style of the training clips — without modifying
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any model weights.
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Key difference from LoRA:
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- ALL generator parameters are frozen (requires_grad=False)
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- Only K×1024 token embeddings receive gradients
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- Latents stay on the decoder's natural manifold → no quality degradation
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- The learned tokens shift WHICH latents are generated, not HOW
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Usage:
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1. Train on your .npz audio features
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2. Load result with SelVA Textual Inversion Loader
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3. Connect to SelVA Sampler optional input
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"""
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import copy
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import random
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import traceback
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from pathlib import Path
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import torch
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import torchaudio
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import comfy.utils
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import folder_paths
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from .utils import SELVA_CATEGORY, get_device, soft_empty_cache
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from selva_core.model.flow_matching import FlowMatching
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from .selva_lora_trainer import (
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_prepare_dataset,
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_spectral_metrics,
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_save_spectrogram,
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)
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# ---------------------------------------------------------------------------
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# Eval helper with token injection
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# ---------------------------------------------------------------------------
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def _eval_sample_ti(generator, learned_tokens, n_tokens,
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feature_utils_orig, dataset, seq_cfg,
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device, dtype, num_steps=25, seed=42, clip_idx=0):
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"""Inference pass with learned tokens injected into text conditioning."""
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generator.eval()
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try:
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_, clip_f_cpu, sync_f_cpu, text_clip_cpu = dataset[clip_idx]
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clip_f = clip_f_cpu.to(device, dtype)
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sync_f = sync_f_cpu.to(device, dtype)
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text_clip = text_clip_cpu.to(device, dtype).clone()
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text_clip[:, -n_tokens:, :] = learned_tokens.detach().unsqueeze(0).to(device, dtype)
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rng = torch.Generator(device=device).manual_seed(seed)
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x0 = torch.randn(1, seq_cfg.latent_seq_len, generator.latent_dim,
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device=device, dtype=dtype, generator=rng)
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eval_fm = FlowMatching(min_sigma=0, inference_mode="euler", num_steps=num_steps)
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def velocity_fn(t, x):
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return generator.forward(x, clip_f, sync_f, text_clip,
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t.reshape(1).to(device, dtype))
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with torch.no_grad():
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x1_pred = eval_fm.to_data(velocity_fn, x0)
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x1_unnorm = generator.unnormalize(x1_pred)
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orig_dev = next(feature_utils_orig.parameters()).device
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if orig_dev != device:
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feature_utils_orig.to(device)
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try:
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spec = feature_utils_orig.decode(x1_unnorm)
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audio = feature_utils_orig.vocode(spec)
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finally:
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if orig_dev != device:
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feature_utils_orig.to(orig_dev)
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audio = audio.float().cpu()
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if audio.dim() == 2:
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audio = audio.unsqueeze(1)
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elif audio.dim() == 3 and audio.shape[1] != 1:
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audio = audio.mean(dim=1, keepdim=True)
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target_rms = 10 ** (-27.0 / 20.0)
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rms = audio.pow(2).mean().sqrt().clamp(min=1e-8)
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audio = (audio * (target_rms / rms))
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peak = audio.abs().max().clamp(min=1e-8)
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if peak > 1.0:
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audio = audio / peak
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return audio.squeeze(0), seq_cfg.sampling_rate
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except Exception as e:
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print(f"[TI Trainer] Eval sample failed: {e}", flush=True)
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traceback.print_exc()
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return None, None
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finally:
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generator.train()
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# ---------------------------------------------------------------------------
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# Node
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# ---------------------------------------------------------------------------
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class SelvaTextualInversionTrainer:
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"""Learns K CLIP token embeddings that steer SelVA toward a target audio style.
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Unlike LoRA, all model weights are frozen. Only the K×1024 embedding tensor
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receives gradients, keeping generated latents on the decoder's natural manifold
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and preserving base model audio quality while shifting generation style.
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"""
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OUTPUT_NODE = True
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CATEGORY = SELVA_CATEGORY
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FUNCTION = "train"
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RETURN_TYPES = ("STRING",)
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RETURN_NAMES = ("embeddings_path",)
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OUTPUT_TOOLTIPS = ("Path to saved .pt embeddings — load with SelVA Textual Inversion Loader.",)
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DESCRIPTION = (
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"Trains K learnable CLIP token embeddings against your audio dataset "
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"with all model weights frozen. The tokens are then injected into the "
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"sampler to guide generation toward the training data style without "
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"degrading audio quality."
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)
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@classmethod
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def INPUT_TYPES(cls):
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return {
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"required": {
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"model": ("SELVA_MODEL",),
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"data_dir": ("STRING", {
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"default": "",
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"tooltip": "Directory containing .npz feature files and paired audio files (same as LoRA trainer).",
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}),
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"output_path": ("STRING", {
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"default": "textual_inversion.pt",
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"tooltip": "Where to save the learned embeddings. Relative paths resolve to ComfyUI output directory.",
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}),
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"n_tokens": ("INT", {
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"default": 4, "min": 1, "max": 16,
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"tooltip": "Number of learnable token vectors. More tokens = more expressive but slower to train. 4 is a good default.",
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}),
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"steps": ("INT", {
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"default": 3000, "min": 100, "max": 50000,
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"tooltip": "Training steps. 3000 is a reasonable starting point.",
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}),
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"lr": ("FLOAT", {
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"default": 1e-3, "min": 1e-5, "max": 1e-1, "step": 1e-5,
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"tooltip": "Learning rate. 1e-3 is a good default for textual inversion (higher than LoRA since there are far fewer parameters).",
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}),
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"batch_size": ("INT", {
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"default": 16, "min": 1, "max": 64,
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"tooltip": "Clips sampled per training step.",
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}),
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"seed": ("INT", {"default": 42, "min": 0, "max": 0xFFFFFFFF}),
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"save_every": ("INT", {
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"default": 1000, "min": 100, "max": 10000,
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"tooltip": "Save a checkpoint and generate an eval sample every N steps.",
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}),
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},
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"optional": {
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"init_text": ("STRING", {
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"default": "",
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"tooltip": "Optional text phrase to warm-start token values via CLIP. Leave empty for random init (N(0, 0.02)). Example: 'industrial sound design'.",
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}),
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"warmup_steps": ("INT", {
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"default": 100, "min": 0, "max": 1000,
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"tooltip": "Linear LR warmup steps.",
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}),
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},
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}
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def train(self, model, data_dir, output_path, n_tokens, steps, lr,
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batch_size, seed, save_every,
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init_text="", warmup_steps=100):
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device = get_device()
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dtype = model["dtype"]
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mode = model["mode"]
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seq_cfg = model["seq_cfg"]
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feature_utils_orig = model["feature_utils"]
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# --- Resolve paths ---
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data_dir = Path(data_dir.strip())
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if not data_dir.is_absolute():
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data_dir = Path(folder_paths.models_dir) / data_dir
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if not data_dir.exists():
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raise FileNotFoundError(f"[TI Trainer] data_dir not found: {data_dir}")
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out_path = Path(output_path.strip())
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if not out_path.is_absolute():
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out_path = Path(folder_paths.get_output_directory()) / out_path
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out_path.parent.mkdir(parents=True, exist_ok=True)
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print(f"\n[TI Trainer] n_tokens={n_tokens} steps={steps} lr={lr:.2e}", flush=True)
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print(f"[TI Trainer] data_dir = {data_dir}", flush=True)
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print(f"[TI Trainer] output = {out_path}\n", flush=True)
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# --- Load dataset (reuse LoRA trainer helper) ---
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dataset = _prepare_dataset(model, data_dir, device)
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# Training must run outside inference_mode so autograd works
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with torch.inference_mode(False), torch.enable_grad():
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return self._train_inner(
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model, dataset, feature_utils_orig, seq_cfg,
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device, dtype, mode,
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data_dir, out_path,
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n_tokens, steps, lr, batch_size,
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warmup_steps, seed, save_every, init_text,
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)
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def _train_inner(
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self, model, dataset, feature_utils_orig, seq_cfg,
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device, dtype, mode,
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data_dir, out_path,
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n_tokens, steps, lr, batch_size,
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warmup_steps, seed, save_every, init_text,
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):
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torch.manual_seed(seed)
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# --- Generator (frozen) ---
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generator = copy.deepcopy(model["generator"]).to(device, dtype)
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generator.requires_grad_(False)
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generator.update_seq_lengths(
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latent_seq_len=seq_cfg.latent_seq_len,
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clip_seq_len=seq_cfg.clip_seq_len,
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sync_seq_len=seq_cfg.sync_seq_len,
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)
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# --- Init learned tokens ---
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# Call encode_text_clip outside the grad context (it has @inference_mode),
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# grab values only (no grad needed), then wrap as nn.Parameter.
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if init_text.strip():
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with torch.no_grad():
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init_embed = feature_utils_orig.encode_text_clip([init_text.strip()])
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# Positions 1:1+n_tokens — after BOS, before EOS — have actual content
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init_vals = init_embed[0, 1:1 + n_tokens, :].detach().clone().float()
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if init_vals.shape[0] < n_tokens:
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# Prompt was very short; pad remaining with small noise
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pad = torch.randn(n_tokens - init_vals.shape[0], init_vals.shape[1]) * 0.02
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init_vals = torch.cat([init_vals, pad], dim=0)
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learned_tokens = torch.nn.Parameter(init_vals.to(device, dtype))
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print(f"[TI Trainer] Init from '{init_text.strip()}' (positions 1–{n_tokens})", flush=True)
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else:
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learned_tokens = torch.nn.Parameter(
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torch.randn(n_tokens, 1024, device=device, dtype=dtype) * 0.02
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)
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print(f"[TI Trainer] Init: random N(0, 0.02)", flush=True)
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# --- Optimizer + scheduler ---
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optimizer = torch.optim.AdamW([learned_tokens], lr=lr, weight_decay=1e-2)
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def lr_lambda(s):
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return s / max(1, warmup_steps) if s < warmup_steps else 1.0
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scheduler = torch.optim.lr_scheduler.LambdaLR(optimizer, lr_lambda)
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fm = FlowMatching(min_sigma=0, inference_mode="euler", num_steps=25)
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# --- Checkpoint dir ---
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ckpt_dir = out_path.parent / out_path.stem
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ckpt_dir.mkdir(parents=True, exist_ok=True)
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# --- Training loop ---
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generator.train()
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optimizer.zero_grad()
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log_interval = 50
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pbar = comfy.utils.ProgressBar(steps)
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loss_history = []
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running_loss = 0.0
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print(f"[TI Trainer] Training {steps} steps batch_size={batch_size}\n", flush=True)
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for step in range(1, steps + 1):
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batch = random.choices(dataset, k=batch_size)
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x1_list, clip_list, sync_list, text_list = zip(*batch)
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x1 = torch.stack([x.squeeze(0) for x in x1_list]).to(device, dtype)
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clip_f = torch.stack([x.squeeze(0) for x in clip_list]).to(device, dtype)
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sync_f = torch.stack([x.squeeze(0) for x in sync_list]).to(device, dtype)
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text_clip = torch.stack([x.squeeze(0) for x in text_list]).to(device, dtype).clone()
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# Inject learned tokens into last n_tokens positions.
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# Must use torch.cat (not in-place assignment) so the computation graph
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# links text_input → learned_tokens and gradients flow correctly.
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text_front = text_clip[:, :-n_tokens, :].detach() # [B, 77-K, D], no grad
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tokens_expanded = learned_tokens.unsqueeze(0).expand(batch_size, -1, -1) # [B, K, D]
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text_input = torch.cat([text_front, tokens_expanded], dim=1) # [B, 77, D] with grad
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x1 = generator.normalize(x1)
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t = torch.rand(batch_size, device=device, dtype=dtype)
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x0 = torch.randn_like(x1)
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xt = fm.get_conditional_flow(x0, x1, t)
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v_pred = generator.forward(xt, clip_f, sync_f, text_input, t)
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loss = fm.loss(v_pred, x0, x1).mean()
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loss.backward()
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torch.nn.utils.clip_grad_norm_([learned_tokens], max_norm=1.0)
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optimizer.step()
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scheduler.step()
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optimizer.zero_grad()
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running_loss += loss.item()
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pbar.update(1)
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if step % log_interval == 0:
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avg = running_loss / log_interval
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loss_history.append(round(avg, 6))
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running_loss = 0.0
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lr_now = scheduler.get_last_lr()[0]
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norm = learned_tokens.norm().item()
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print(f"[TI Trainer] step {step:5d}/{steps} "
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f"loss={avg:.4f} lr={lr_now:.2e} "
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f"token_norm={norm:.4f}", flush=True)
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if step % save_every == 0 or step == steps:
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# Save checkpoint
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ckpt = {
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"embeddings": learned_tokens.detach().cpu(),
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"n_tokens": n_tokens,
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"step": step,
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"init_text": init_text,
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"lr": lr,
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"steps": steps,
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"loss_history": loss_history,
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}
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ckpt_path = ckpt_dir / f"step_{step:05d}.pt"
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torch.save(ckpt, str(ckpt_path))
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# Eval sample
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wav, sr = _eval_sample_ti(
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generator, learned_tokens, n_tokens,
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feature_utils_orig, dataset, seq_cfg,
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device, dtype, seed=seed,
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)
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if wav is not None:
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wav_path = ckpt_dir / f"step_{step:05d}.wav"
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try:
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torchaudio.save(str(wav_path), wav, sr)
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except RuntimeError:
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import soundfile as sf
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sf.write(str(wav_path), wav.squeeze(0).numpy(), sr)
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try:
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metrics = _spectral_metrics(wav, sr)
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_save_spectrogram(wav, sr, ckpt_dir / f"step_{step:05d}.png")
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print(f"[TI Trainer] step {step} "
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f"centroid={metrics['spectral_centroid_hz']:.0f}Hz "
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f"flatness={metrics['spectral_flatness']:.4f} "
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f"hf={metrics['hf_energy_ratio']:.3f}", flush=True)
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except Exception as e:
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print(f"[TI Trainer] Spectral/spectrogram failed: {e}", flush=True)
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print(f"[TI Trainer] Checkpoint: {ckpt_path}", flush=True)
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# --- Final save ---
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final = {
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"embeddings": learned_tokens.detach().cpu(),
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"n_tokens": n_tokens,
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"step": steps,
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"init_text": init_text,
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"lr": lr,
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"steps": steps,
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"loss_history": loss_history,
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}
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torch.save(final, str(out_path))
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print(f"\n[TI Trainer] Done. Saved: {out_path}", flush=True)
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soft_empty_cache()
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return (str(out_path),)
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