ComfyUI/comfy/ldm/lightricks/vae/audio_vae.py
jjdejong ddac8fd48e fix: cast mel_spec to waveform dtype in AudioVAE encode to support --bf16-vae
waveform_to_mel() performs mel filterbank computation in float32
regardless of input dtype, discarding the bfloat16 cast applied by
the VAE encode path in sd.py. The resulting float32 mel spectrogram
is then passed to the bfloat16 autoencoder encoder, causing a
RuntimeError at the first conv layer when --bf16-vae is active.

Fix by casting mel_spec to waveform.dtype (already set to vae_dtype
by the caller) before passing to self.autoencoder.encode(). This is
a no-op when --bf16-vae is not used.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-05-13 22:56:59 +02:00

283 lines
10 KiB
Python

import json
from dataclasses import dataclass
import math
import torch
import torchaudio
import comfy.model_management
import comfy.model_patcher
import comfy.utils as utils
from comfy.ldm.mmaudio.vae.distributions import DiagonalGaussianDistribution
from comfy.ldm.lightricks.symmetric_patchifier import AudioPatchifier
from comfy.ldm.lightricks.vae.causal_audio_autoencoder import (
CausalityAxis,
CausalAudioAutoencoder,
)
from comfy.ldm.lightricks.vocoders.vocoder import Vocoder, VocoderWithBWE
LATENT_DOWNSAMPLE_FACTOR = 4
@dataclass(frozen=True)
class AudioVAEComponentConfig:
"""Container for model component configuration extracted from metadata."""
autoencoder: dict
vocoder: dict
@classmethod
def from_metadata(cls, metadata: dict) -> "AudioVAEComponentConfig":
assert metadata is not None and "config" in metadata, "Metadata is required for audio VAE"
raw_config = metadata["config"]
if isinstance(raw_config, str):
parsed_config = json.loads(raw_config)
else:
parsed_config = raw_config
audio_config = parsed_config.get("audio_vae")
vocoder_config = parsed_config.get("vocoder")
assert audio_config is not None, "Audio VAE config is required for audio VAE"
assert vocoder_config is not None, "Vocoder config is required for audio VAE"
return cls(autoencoder=audio_config, vocoder=vocoder_config)
class ModelDeviceManager:
"""Manages device placement and GPU residency for the composed model."""
def __init__(self, module: torch.nn.Module):
load_device = comfy.model_management.get_torch_device()
offload_device = comfy.model_management.vae_offload_device()
self.patcher = comfy.model_patcher.ModelPatcher(module, load_device, offload_device)
def ensure_model_loaded(self) -> None:
comfy.model_management.free_memory(
self.patcher.model_size(),
self.patcher.load_device,
)
comfy.model_management.load_model_gpu(self.patcher)
def move_to_load_device(self, tensor: torch.Tensor) -> torch.Tensor:
return tensor.to(self.patcher.load_device)
@property
def load_device(self):
return self.patcher.load_device
class AudioLatentNormalizer:
"""Applies per-channel statistics in patch space and restores original layout."""
def __init__(self, patchfier: AudioPatchifier, statistics_processor: torch.nn.Module):
self.patchifier = patchfier
self.statistics = statistics_processor
def normalize(self, latents: torch.Tensor) -> torch.Tensor:
channels = latents.shape[1]
freq = latents.shape[3]
patched, _ = self.patchifier.patchify(latents)
normalized = self.statistics.normalize(patched)
return self.patchifier.unpatchify(normalized, channels=channels, freq=freq)
def denormalize(self, latents: torch.Tensor) -> torch.Tensor:
channels = latents.shape[1]
freq = latents.shape[3]
patched, _ = self.patchifier.patchify(latents)
denormalized = self.statistics.un_normalize(patched)
return self.patchifier.unpatchify(denormalized, channels=channels, freq=freq)
class AudioPreprocessor:
"""Prepares raw waveforms for the autoencoder by matching training conditions."""
def __init__(self, target_sample_rate: int, mel_bins: int, mel_hop_length: int, n_fft: int):
self.target_sample_rate = target_sample_rate
self.mel_bins = mel_bins
self.mel_hop_length = mel_hop_length
self.n_fft = n_fft
def resample(self, waveform: torch.Tensor, source_rate: int) -> torch.Tensor:
if source_rate == self.target_sample_rate:
return waveform
return torchaudio.functional.resample(waveform, source_rate, self.target_sample_rate)
def waveform_to_mel(
self, waveform: torch.Tensor, waveform_sample_rate: int, device
) -> torch.Tensor:
waveform = self.resample(waveform, waveform_sample_rate)
mel_transform = torchaudio.transforms.MelSpectrogram(
sample_rate=self.target_sample_rate,
n_fft=self.n_fft,
win_length=self.n_fft,
hop_length=self.mel_hop_length,
f_min=0.0,
f_max=self.target_sample_rate / 2.0,
n_mels=self.mel_bins,
window_fn=torch.hann_window,
center=True,
pad_mode="reflect",
power=1.0,
mel_scale="slaney",
norm="slaney",
).to(device)
mel = mel_transform(waveform)
mel = torch.log(torch.clamp(mel, min=1e-5))
return mel.permute(0, 1, 3, 2).contiguous()
class AudioVAE(torch.nn.Module):
"""High-level Audio VAE wrapper exposing encode and decode entry points."""
def __init__(self, state_dict: dict, metadata: dict):
super().__init__()
component_config = AudioVAEComponentConfig.from_metadata(metadata)
vae_sd = utils.state_dict_prefix_replace(state_dict, {"audio_vae.": ""}, filter_keys=True)
vocoder_sd = utils.state_dict_prefix_replace(state_dict, {"vocoder.": ""}, filter_keys=True)
self.autoencoder = CausalAudioAutoencoder(config=component_config.autoencoder)
if "bwe" in component_config.vocoder:
self.vocoder = VocoderWithBWE(config=component_config.vocoder)
else:
self.vocoder = Vocoder(config=component_config.vocoder)
self.autoencoder.load_state_dict(vae_sd, strict=False)
self.vocoder.load_state_dict(vocoder_sd, strict=False)
autoencoder_config = self.autoencoder.get_config()
self.normalizer = AudioLatentNormalizer(
AudioPatchifier(
patch_size=1,
audio_latent_downsample_factor=LATENT_DOWNSAMPLE_FACTOR,
sample_rate=autoencoder_config["sampling_rate"],
hop_length=autoencoder_config["mel_hop_length"],
is_causal=autoencoder_config["is_causal"],
),
self.autoencoder.per_channel_statistics,
)
self.preprocessor = AudioPreprocessor(
target_sample_rate=autoencoder_config["sampling_rate"],
mel_bins=autoencoder_config["mel_bins"],
mel_hop_length=autoencoder_config["mel_hop_length"],
n_fft=autoencoder_config["n_fft"],
)
self.device_manager = ModelDeviceManager(self)
def encode(self, audio: dict) -> torch.Tensor:
"""Encode a waveform dictionary into normalized latent tensors."""
waveform = audio["waveform"]
waveform_sample_rate = audio["sample_rate"]
input_device = waveform.device
# Ensure that Audio VAE is loaded on the correct device.
self.device_manager.ensure_model_loaded()
waveform = self.device_manager.move_to_load_device(waveform)
expected_channels = self.autoencoder.encoder.in_channels
if waveform.shape[1] != expected_channels:
if waveform.shape[1] == 1:
waveform = waveform.expand(-1, expected_channels, *waveform.shape[2:])
else:
raise ValueError(
f"Input audio must have {expected_channels} channels, got {waveform.shape[1]}"
)
mel_spec = self.preprocessor.waveform_to_mel(
waveform, waveform_sample_rate, device=self.device_manager.load_device
)
latents = self.autoencoder.encode(mel_spec.to(dtype=waveform.dtype))
posterior = DiagonalGaussianDistribution(latents)
latent_mode = posterior.mode()
normalized = self.normalizer.normalize(latent_mode)
return normalized.to(input_device)
def decode(self, latents: torch.Tensor) -> torch.Tensor:
"""Decode normalized latent tensors into an audio waveform."""
original_shape = latents.shape
# Ensure that Audio VAE is loaded on the correct device.
self.device_manager.ensure_model_loaded()
latents = self.device_manager.move_to_load_device(latents)
latents = self.normalizer.denormalize(latents)
target_shape = self.target_shape_from_latents(original_shape)
mel_spec = self.autoencoder.decode(latents, target_shape=target_shape)
waveform = self.run_vocoder(mel_spec)
return self.device_manager.move_to_load_device(waveform)
def target_shape_from_latents(self, latents_shape):
batch, _, time, _ = latents_shape
target_length = time * LATENT_DOWNSAMPLE_FACTOR
if self.autoencoder.causality_axis != CausalityAxis.NONE:
target_length -= LATENT_DOWNSAMPLE_FACTOR - 1
return (
batch,
self.autoencoder.decoder.out_ch,
target_length,
self.autoencoder.mel_bins,
)
def num_of_latents_from_frames(self, frames_number: int, frame_rate: int) -> int:
return math.ceil((float(frames_number) / frame_rate) * self.latents_per_second)
def run_vocoder(self, mel_spec: torch.Tensor) -> torch.Tensor:
audio_channels = self.autoencoder.decoder.out_ch
vocoder_input = mel_spec.transpose(2, 3)
if audio_channels == 1:
vocoder_input = vocoder_input.squeeze(1)
elif audio_channels != 2:
raise ValueError(f"Unsupported audio_channels: {audio_channels}")
return self.vocoder(vocoder_input)
@property
def sample_rate(self) -> int:
return int(self.autoencoder.sampling_rate)
@property
def mel_hop_length(self) -> int:
return int(self.autoencoder.mel_hop_length)
@property
def mel_bins(self) -> int:
return int(self.autoencoder.mel_bins)
@property
def latent_channels(self) -> int:
return int(self.autoencoder.decoder.z_channels)
@property
def latent_frequency_bins(self) -> int:
return int(self.mel_bins // LATENT_DOWNSAMPLE_FACTOR)
@property
def latents_per_second(self) -> float:
return self.sample_rate / self.mel_hop_length / LATENT_DOWNSAMPLE_FACTOR
@property
def output_sample_rate(self) -> int:
output_rate = getattr(self.vocoder, "output_sample_rate", None)
if output_rate is not None:
return int(output_rate)
upsample_factor = getattr(self.vocoder, "upsample_factor", None)
if upsample_factor is None:
raise AttributeError(
"Vocoder is missing upsample_factor; cannot infer output sample rate"
)
return int(self.sample_rate * upsample_factor / self.mel_hop_length)
def memory_required(self, input_shape):
return self.device_manager.patcher.model_size()