ltx-2.5-granules

LTX-2.5 granules — per-block weight streaming (MLX)

A re-layout of LTX-2.5's DiT into per-block granule files, so the transformer can be streamed from SSD during denoise instead of held resident. Same bytes, reorganised.

Consumed by ltx-2-mlx-swift via BlockStreamKit. Sibling of xocialize/ltx-2.3-granules.

Fetch these INSTEAD of the transformer, not as well

Each tree carries a globals.granule sidecar holding the 59 non-block tensors, so a consumer binds without the source checkpoint present at all. Downloading both would double the DiT's disk for no benefit.

Output is bit-identical, not merely close

Streamed vs resident is a memcmp gate, not a cosine gate — paired with a poisoned-slot negative control proving the comparison can fail. Quality is not a consideration when choosing this path.

What it buys, and what it costs

Buys: the resident DiT floor disappears (slots are ~1.5 GiB for q8, ~2.9 GiB for bf16). That is what makes LTX-2.5 fit 24 GB and 32 GB machines at all, and on 64 GB it measured faster than resident — eviction otherwise reloads the whole DiT every stage.

Costs: ~6× read amplification (a full sweep per denoise step rather than one load). Overlapped, so no wall-clock penalty at real generation sizes — but real SSD and power load, and unmeasured on battery.

⚠️ Streaming is only profitable above a token threshold the runtime computes from measured IO vs compute. Below it the consumer falls back to resident output-invisibly. On small-N tiers that estimate is noisy enough to flip run to run, so the consumer pins the decision there rather than letting it vary.

Provenance

Each manifest.json records source_repo + source_revision alongside per-file SHA-256. Those stamps are verified at layout time against the live Hub — the declared revision must resolve and the declared file size must match — so a downloader can check what a tree came from rather than inferring it from a filename.

Licence

LTX-2 Community License — see LICENSE.md and the acceptable-use snapshot. These are a derivative of Lightricks LTX-2.5 and carry its terms, including the Attachment A revenue gate and non-compete. Redistribution permitted under §3 with those terms propagated.