Index-Echo-S2TT-2B-GGUF
Official GGUF conversion of the text LLM backbone (llm/) of IndexTeam/Index-Echo-S2TT-2B, part of the Index-Echo speech-to-text translation (S2TT) model family by bilibili.
Note: LLM backbone only. The audio tower, connector and speech-synthesis stack are not included - llama.cpp cannot run the full speech pipeline. For full speech-to-text translation (S2TT) inference, use the original checkpoint or the FP8 build in Index-Echo-S2TT-2B-FP8, which ships the complete pipeline with an FP8-quantized LLM.
Converted with llama.cpp (master, 2026-10); static post-training quantization, all bit-widths in this single repository.
Provided files
(sorted by size)
| File | Size | Notes |
|---|---|---|
| mmproj-Q8_0 | 0.36 GB | multi-modal projector supplement |
| mmproj-f16 | 0.67 GB | multi-modal projector supplement |
| Q2_K | 0.99 GB | 2-bit, significant quality loss |
| Q3_K_S | 1.05 GB | 3-bit, noticeable quality loss |
| Q3_K_M | 1.13 GB | 3-bit, noticeable quality loss |
| Q3_K_L | 1.20 GB | 3-bit, noticeable quality loss |
| IQ4_XS | 1.23 GB | 4-bit I-quant, small |
| Q4_K_S | 1.25 GB | 4-bit, slightly smaller/faster |
| Q4_K_M | 1.31 GB | 4-bit, good balance, recommended |
| Q5_K_S | 1.42 GB | 5-bit, low quality loss |
| Q5_K_M | 1.45 GB | 5-bit, low quality loss |
| Q6_K | 1.61 GB | 6-bit, very low quality loss |
| Q8_0 | 2.08 GB | 8-bit, near-lossless |
| f16 | 3.90 GB | 16-bit, lossless conversion baseline |
The mmproj files are the multi-modal projector for the vision tower; they are only needed for image-input use with llama-mtmd-cli. For text-only translation, the plain GGUF files suffice.
Usage
# Run the recommended Q4_K_M directly:
llama serve -hf IndexTeam/Index-Echo-S2TT-2B-GGUF:Q4_K_M
llama cli -hf IndexTeam/Index-Echo-S2TT-2B-GGUF:Q4_K_M
Consistency validation
Before release, each quantization tier was validated on GPU (NVIDIA A100) against the F16 conversion: per-token KL divergence / RMS delta-p via llama-perplexity, plus greedy-generation spot checks against the original BF16 weights (transformers reference). Generation outputs of Q4_K_M matched the reference almost verbatim.
Converted and published by the Index team, 2026-10-03.