sa_audio
Lazy-loading pipeline wrapper around OobleckVAE.
Two reasons this exists rather than using OobleckVAE directly:
- The underlying VAE is fetched on first
encode/decodecall, not at construction — lets pipelines build the module tree on CPU before knowing the target device. - The lazy VAE's params are hidden from
named_parameters()so the FastVideo pipeline-component loader doesn't try to match Oobleck's safetensors against the host pipeline's converted-repo state dict.
For standalone use prefer OobleckVAE.from_pretrained(...) directly.
fastvideo.models.vaes.sa_audio.OobleckVAEConfig
OobleckVAEConfig(arch_config: VAEArchConfig = OobleckVAEArchConfig(), load_encoder: bool = True, load_decoder: bool = True, tile_sample_min_height: int = 256, tile_sample_min_width: int = 256, tile_sample_min_num_frames: int = 16, tile_sample_stride_height: int = 192, tile_sample_stride_width: int = 192, tile_sample_stride_num_frames: int = 12, blend_num_frames: int = 0, use_tiling: bool = False, use_temporal_tiling: bool = False, use_parallel_tiling: bool = False, use_temporal_scaling_frames: bool = True, pretrained_path: str = 'stabilityai/stable-audio-open-1.0', pretrained_subfolder: str = 'vae', pretrained_dtype: str = 'float16', *, _resolved_attention_backend: AttentionBackendEnum | None = None)
FastVideo VAE config wrapping the Oobleck arch.
Audio VAEs don't use the temporal/spatial tiling defaults that the base VAEConfig is shaped for (those exist for video VAEs); they are retained but irrelevant for audio.
fastvideo.models.vaes.sa_audio.SAAudioVAEModel
SAAudioVAEModel(config: OobleckVAEConfig)
Pipeline-glue lazy loader around OobleckVAE.
Source
class SAAudioVAEModel(nn.Module):
"""Pipeline-glue lazy loader around `OobleckVAE`."""
def __init__(self, config: OobleckVAEConfig) -> None:
super().__init__()
self.config = config
arch = config.arch_config
self.pretrained_path: str = config.pretrained_path
self.pretrained_subfolder: str | None = config.pretrained_subfolder
self.pretrained_dtype: str = config.pretrained_dtype
self.sampling_rate: int = arch.sampling_rate
self.audio_channels: int = arch.audio_channels
self.decoder_input_channels: int = arch.decoder_input_channels
self._oobleck_vae = None
def named_parameters(self, prefix: str = "", recurse: bool = True):
# Hide the lazy-loaded VAE — its weights are fetched separately
# and shouldn't appear in the host pipeline's loader sweep.
for name, param in super().named_parameters(prefix=prefix, recurse=recurse):
if name.startswith("_oobleck_vae.") or name == "_oobleck_vae":
continue
yield name, param
def _build(self, device: torch.device | None = None):
from fastvideo.models.vaes.oobleck import OobleckVAE
path = self.pretrained_path
if not path:
raise ValueError("OobleckVAEConfig.pretrained_path must be set; expected "
"`stabilityai/stable-audio-open-1.0` or a local path.")
dtype = getattr(torch, self.pretrained_dtype, torch.float32)
# If the caller already pointed us at the VAE dir directly, drop
# the subfolder. Otherwise pass through (default "vae").
subfolder: str | None = self.pretrained_subfolder
if subfolder and os.path.isdir(path) and os.path.isfile(os.path.join(path, "config.json")):
subfolder = None
model = OobleckVAE.from_pretrained(path, subfolder=subfolder, torch_dtype=dtype)
if device is not None:
model = model.to(device=device)
model.eval()
return model
@property
def oobleck_vae(self):
if self._oobleck_vae is None:
self._oobleck_vae = self._build()
return self._oobleck_vae
# Back-compat alias: callers that imported this earlier referred to
# the underlying VAE as `sa_audio_vae_model`. Both names point at the
# same object.
@property
def sa_audio_vae_model(self):
return self.oobleck_vae
@property
def hop_length(self) -> int:
return int(self.oobleck_vae.hop_length)
def _move_to_input_device(self, model, ref: torch.Tensor):
if ref is None:
return model
first_param = next(model.parameters(), None)
if first_param is not None and first_param.device != ref.device:
model = model.to(device=ref.device)
self._oobleck_vae = model
return model
def decode(self, latent: torch.Tensor) -> torch.Tensor:
"""Decode an audio latent (`[B, C_latent, L]`) -> waveform
(`[B, audio_channels, samples]`).
"""
model = self.oobleck_vae
model = self._move_to_input_device(model, latent)
with torch.no_grad():
out = model.decode(latent.to(next(model.parameters()).dtype))
if hasattr(out, "sample"):
return out.sample
return out
def encode(self, waveform: torch.Tensor, sample_posterior: bool = False) -> torch.Tensor:
"""Encode `[B, C_audio, samples]` -> latent `[B, C_latent, L]`.
`sample_posterior=False` (default): deterministic mean.
`sample_posterior=True`: stochastic sample (`mean + softplus(scale) * randn`).
"""
model = self.oobleck_vae
model = self._move_to_input_device(model, waveform)
with torch.no_grad():
out = model.encode(waveform.to(next(model.parameters()).dtype))
if hasattr(out, "latent_dist"):
out = out.latent_dist
return out.sample() if sample_posterior else out.mode()</code></pre></details>
fastvideo.models.vaes.sa_audio.SAAudioVAEModel.named_parameters
named_parameters(prefix: str = '', recurse: bool = True)
Source
def named_parameters(self, prefix: str = "", recurse: bool = True):
# Hide the lazy-loaded VAE — its weights are fetched separately
# and shouldn't appear in the host pipeline's loader sweep.
for name, param in super().named_parameters(prefix=prefix, recurse=recurse):
if name.startswith("_oobleck_vae.") or name == "_oobleck_vae":
continue
yield name, param
fastvideo.models.vaes.sa_audio.SAAudioVAEModel.decode
decode(latent: torch.Tensor) -> torch.Tensor
Decode an audio latent ([B, C_latent, L]) -> waveform
([B, audio_channels, samples]).
Source
def decode(self, latent: torch.Tensor) -> torch.Tensor:
"""Decode an audio latent (`[B, C_latent, L]`) -> waveform
(`[B, audio_channels, samples]`).
"""
model = self.oobleck_vae
model = self._move_to_input_device(model, latent)
with torch.no_grad():
out = model.decode(latent.to(next(model.parameters()).dtype))
if hasattr(out, "sample"):
return out.sample
return out
fastvideo.models.vaes.sa_audio.SAAudioVAEModel.encode
encode(waveform: torch.Tensor, sample_posterior: bool = False) -> torch.Tensor
Encode [B, C_audio, samples] -> latent [B, C_latent, L].
sample_posterior=False (default): deterministic mean.
sample_posterior=True: stochastic sample (mean + softplus(scale) * randn).
Source
def encode(self, waveform: torch.Tensor, sample_posterior: bool = False) -> torch.Tensor:
"""Encode `[B, C_audio, samples]` -> latent `[B, C_latent, L]`.
`sample_posterior=False` (default): deterministic mean.
`sample_posterior=True`: stochastic sample (`mean + softplus(scale) * randn`).
"""
model = self.oobleck_vae
model = self._move_to_input_device(model, waveform)
with torch.no_grad():
out = model.encode(waveform.to(next(model.parameters()).dtype))
if hasattr(out, "latent_dist"):
out = out.latent_dist
return out.sample() if sample_posterior else out.mode()</code></pre></details>