Extend the JoyAI cross-shot memory bank from video-only to paired audio-video,
the part that distinguishes JoyAI-Echo from a generic video-consistency trick.
- _JoyAIMemoryBank now stores (video, audio) pairs under the same pin/roll policy;
frames()/audio() stay 1:1. Audio half is None until joyai_audio_memory is on, so
the phase-1 video path is byte-identical.
- _append_joyai_audio_memory pins each banked prior-shot audio latent into the
chunk's audio stream as a fully-protected (mask=0) tail, cropped back off after
sampling (_crop_audio_tail). The audio analogue of the video guide bank; rides
native audio self-attention since LTX has no audio guide-attention API.
- _harvest_joyai_audio harvests the paired audio frame, position-matched to video.
- v2a_grad_scale scales the model's trained video->audio cross-attention via
reversible forward hooks on each AV block's video_to_audio_attn submodule
(JoyAI uses 2.0). 1.0 installs no hook -> native behavior, zero overhead.
- joyai_audio_memory + v2a_grad_scale wired through sample(), batch training,
refinement context, run_mechanisms, INPUT_TYPES (append-only), and editor knobs.
Deliberately breaks the audio pass-through invariant, so both are opt-in and
off/native by default. 3 new bank tests; zero regressions (same 12 pre-existing
stale-mock failures before/after).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
