LTX 2.5 reuses LTXAVModel/LTXBaseModel behind config flags, so the samplers,
the identity-transfer wrappers and the guide path all bind to it unchanged.
Two places assumed 2.3 specifics, and both would have gone wrong quietly.
The AV channel split was a hardcoded width table. From 2.5 on comfy reads the
video/audio projection widths off the checkpoint rather than assuming them, so
a checkpoint can ship a pair the table has never seen — and an unrecognised
width made ltxav_video_channels return the FULL width, which silently steers
the audio text context along with the video one. The only symptom would have
been degraded audio. The split is now measured off the live model when one is
on hand; the table stays as the fallback.
Decode-time noise only ever reached VideoVAE.decode. 2.5's diffusion decoder
takes no timestep and seeds itself, but it is an nn.Module, so stamping the
attributes onto it succeeded and was then ignored — a knob that reads as live
and does nothing. It is now capability-tested against the real contract
(hasattr decode_timestep, not a class name) and says so when it cannot apply.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
