thepatch/t5gemma-b-b-ul2-GGUF

T5Gemma-b-b-ul2 Encoder + Tokenizer — GGUF (for sa3.cpp)

The shared text encoder + tokenizer for sa3.cpp. GGUF conversion of the frozen google/t5gemma-b-b-ul2 encoder (encoder-only at inference) that Stable Audio 3 uses to embed text prompts.

This component is identical across all three SA3 variants (medium, small-music, small-sfx), so it lives in its own repo and is fetched once — the per-variant conditioner ships separately in each model repo. Validated against the PyTorch reference at cosine similarity ~1.0.

Files

component	file	size	notes
text encoder	t5gemma-b-b-ul2-encoder-0.3B-v1.0-F16.gguf	537 MiB	default — equivalent to F32
text encoder	t5gemma-b-b-ul2-encoder-0.3B-v1.0-F32.gguf	1074 MiB	reference precision
text encoder	t5gemma-b-b-ul2-encoder-0.3B-v1.0-Q8_0.gguf	285 MiB	smallest; a small, real tradeoff
tokenizer	t5gemma-b-b-ul2-v1.0-vocab.gguf	14 MiB	Gemma byte-fallback BPE

The encoder carries no conditioner — that ships per-variant in each model repo.

picking an encoder precision

Measured against an F32 control, swapping only the encoder:

encoder	conditioning cosine	generated-audio cosine
F16	0.999995	0.999848
Q8_0	0.999547	0.999108

F16 is what sa3.cpp downloads and resolves by default, and it is a size win rather than a fidelity substitution. Q8_0 is offered for tight-memory installs; it is a small but real tradeoff, so it is never auto-selected — ask for it by name.

Q4_K_M is not published for this encoder, on evidence rather than caution: it is slower than F32 here (the T5 forward is too small to amortize dequant, unlike the DiT) while dropping generated-audio cosine to ~0.80, which is a different piece of music rather than a degraded one. Q8_0 dominates it on every axis.

Select a precision with --t5-encoding f16|f32|q8_0, independently of the --encoding that picks the DiT/SAME tier — the combination worth having on a small device is a quantized DiT with an F16 encoder. This works the same way at inference (sa3-generate) and at training (sa3-train).

Pair these with any SA3 variant repo's DiT + SAME + conditioner: medium · small-music · small-sfx. tools/download_models.py fetches this repo automatically alongside whichever variant you pick.

License

This is a format conversion of google/t5gemma-b-b-ul2, released under the Gemma Terms of Use (including the use restrictions in Section 3.2). Those terms carry over to this converted encoder + tokenizer.

Relationship to the original

A format conversion (weights → GGUF) for inference in sa3.cpp — no retraining. See sa3.cpp/docs/DISTRIBUTION.md.