PDO_S2TT

Official checkpoints for the ICASSP 2027 submission:

PERSISTENT DELIVERY OPTIMIZATION FOR STREAMING SPEECH-TO-TEXT TRANSLATION WITH REVISIONS

PDO is a history-conditioned, direct streaming speech-to-text translation policy. It receives a growing English speech prefix together with the previously displayed translation and may wait, append, or revise the complete visible target-language draft.

Inference, evaluation, and PDO training code

Released checkpoints

File	Description
pdo_s2tt.pt	Inference-only LoRA and history-conditioning weights
pdo_s2tt_sft.pt	SFT initialization for reproducing PDO reinforcement learning

Both checkpoints use Qwen/Qwen3-ASR-1.7B as the base model. The public repository includes the complete multilingual PDO reinforcement-learning stage, its frozen FLEURS training targets, evaluation code, and a four-GPU smoke test. The preceding supervised-training stages and optimizer state are not included.

Supported directions

• En->Zh
• En->De
• En->Es
• En->Ja
• En->Fr

Download

The paper release is pinned to revision 62c27b03aa1d7da1b739e43e815796029ee243f5:

hf download hf-wzx1205/PDO_S2TT pdo_s2tt.pt \
  --revision 62c27b03aa1d7da1b739e43e815796029ee243f5 \
  --local-dir checkpoints

hf download hf-wzx1205/PDO_S2TT pdo_s2tt_sft.pt \
  --revision 62c27b03aa1d7da1b739e43e815796029ee243f5 \
  --local-dir checkpoints

See the GitHub training instructions for the released G=4 recipe and complete reproduction workflow.

FLEURS TEST results

Direction	BLEU	COMET	chrF++	FTL	FRD	LAAL-CU mean / P90	RTF
En->Zh	38.16	86.31	26.92	2.00	2.33	3.53 / 6.61	.39
En->De	29.57	84.22	57.03	2.00	2.42	3.08 / 5.65	.57
En->Es	23.35	83.57	50.88	2.00	2.44	2.51 / 4.44	.57
En->Ja	28.66	88.50	26.47	2.00	2.47	3.67 / 6.23	.57
En->Fr	38.16	84.26	62.06	2.00	2.44	2.46 / 4.93	.59
Macro	31.58	85.37	44.67	2.00	2.42	3.05 / 5.66	.54

FRD and RTF include measured computation; the values above were measured on one RTX 4090. All five directions have 100% final-output coverage.

Intended use

These checkpoints are released for research and reproducibility in revision-capable simultaneous speech translation. They should be used with the accompanying inference and evaluation code. Performance outside the five released English-to-X directions has not been established.

License

The released PDO_S2TT checkpoints are licensed under the Apache License 2.0. The separately distributed Qwen/Qwen3-ASR-1.7B base model is also released under Apache-2.0. FLEURS data and references remain subject to their original dataset licenses.