G-STAR: End-to-End Global Speaker-Tracking Attributed Recognition
Authors: Jing Peng, Ziyi Chen, Haoyu Li, Yucheng Wang, Duo Ma, Mengtian Li, Yunfan Du, Dezhu Xu, Kai Yu, Shuai Wang
Organizations: Shanghai Jiao Tong University · Shenzhen Research Institute of Big Data · Nanjing University · Central Media Technology Institute, Huawei · ETH Zürich
We study timestamped speaker-attributed automatic speech recognition (SA-ASR) for long-form, multi-party speech with overlap. In this setting, chunk-wise inference must preserve meeting-level speaker identity consistency while producing time-stamped, speaker-labeled transcripts. Prior Speech-LLM systems tend to prioritize either local diarization or global labeling, lacking the ability to jointly model fine-grained temporal boundaries and robust cross-chunk identity linking. We propose G-STAR, an end-to-end framework that couples a cache-conditioned speaker-tracking module with a Speech-LLM transcription backbone. The tracker provides structured speaker cues with temporal grounding, and the LLM generates attributed text conditioned on these cues. G-STAR supports component-wise optimization and joint end-to-end training, enabling flexible learning under heterogeneous supervision and domain shift. Under chunk-wise decoding protocols, experiments on both oracle-segmented local evaluation and full-meeting global evaluation show strong speaker-attributed transcription performance.
Figures & tables
Figure 1: Illustration of Streaming Sortformer with AOSC. The cache stores arrival-order speaker states across chunks and reuses them to keep speaker identities consistent when speakers reappear.
Figure 2: Overview of G-STAR Structure. The left panel illustrates the proposed G-STAR model architecture, which features a dual-branch encoder design comprising ASR and speaker diarization modules to support chunk-wise inference. The right panel outlines the three-stage training strategy for G-STAR, progressing sequentially from Speech-Language Pre-training to local SA-ASR (Cross-modal Alignment) and finally to global SA-ASR (End-to-End Fine-tuning).
Group
Component
AMI
Fisher
MLC
Candor
cpWER/DER ↓
cpWER/DER ↓
cpWER/DER ↓
cpWER/DER ↓
NVIDIA cascade
Sortformer (SD) ( Park et al., 2024 )
– / 29.87
– / 18.33
– / 17.76
– / 30.92
Parakeet (ASR) ( Wang et al., 2025 )
24.62 / –
27.73 / –
25.90 / –
27.44 / –
E2E SA-ASR
Vibevoice-ASR ( Peng et al., 2026 )
30.51 / 31.99
15.18 / 17.68
21.74 / 14.01
22.12 / 30.89
MOSS-Diarizen ( MOSI.AI et al., 2026 )
25.13 / 32.20
11.69 / 21.61
14.16 / 10.58
16.38 / 31.76
G-STAR
Ours
24.86 / 19.00
10.29 / 8.18
13.90 / 6.49
14.54 / 17.56
Table 1: Performance comparison in the local setting (audio up to 20s) with oracle VAD/segmentation, reported in cpWER/DER (%). The NVIDIA default cascade is shown as a two-row group: Sortformer for SD/DER and Parakeet for ASR/cpWER. DER is computed with collar 0. Bold indicates the best result.
Group
Component
Fisher
MLC
Candor
AMI
cpWER/DER ↓
cpWER/DER ↓
cpWER/DER ↓
cpWER/DER ↓
NVIDIA cascade
Sortformer (SD) ( Park et al., 2024 )
– / 15.21
– / 21.92
– / 18.03
– / 28.35
Parakeet (ASR) ( Wang et al., 2025 )
24.41 / –
31.03 / –
26.92 / –
35.70 / –
Speech-LLM
Vibevoice-ASR ( Peng et al., 2026 )
25.03 / 27.15
25.41 / 19.83
27.24 / 25.68
34.19 / 39.95
Controlled
Late-fusion cascade
21.01 / 23.41
23.18 / 21.38
17.62 / 17.67
39.52 / 37.63
G-STAR
Ours
16.44 / 16.85
17.15 / 14.25
15.17 / 24.89
30.85 / 32.23
Table 2: Global (meeting-level) performance comparison, reported in cpWER/DER (%). The NVIDIA default cascade is shown as separate SD and ASR components; the controlled cascade uses the same main components as G-STAR but applies late fusion. DER is computed with collar 0. Bold indicates the best result.
System
2 speakers
3–4 speakers
Avg.
cpWER/DER ↓
cpWER/DER ↓
cpWER/DER ↓
Vibevoice-ASR ( Peng et al., 2026 )
11.10 / 14.83
54.48 / 38.33
47.64 / 34.62
Cluster-based Pipeline
23.56 / 14.20
41.14 / 30.76
38.37 / 28.15
G-STAR
10.42 / 4.86
38.85 / 28.59
34.37 / 24.88
Table 3: Global SA-ASR performance on the internal test set, reported in cpWER/DER (%). DER is computed with collar 0.5.
Figure 3: Effect of the interleave ratio K on MLC SA-ASR performance in the local setting. Smaller K injects speaker cues more frequently, while larger K provides sparser speaker conditioning.
Hierarchical CE loss
Interleave Temporal Fusion
AMI
Fisher
Candor
cpWER/DER ↓
cpWER/DER ↓
cpWER/DER ↓
×
✓
26.33 / 21.06
10.88 / 10.24
14.97 / 20.21
✓
×
28.63 / 21.28
14.23 / 9.02
18.30 / 18.10
✓
✓
24.86 / 19.00
10.29 / 8.18
14.54 / 17.56
Table 4: Ablation study of model configuration under local setting.
Natural conversations make both speech recognition and speaker attribution challenging for ASR, as speakers take turns, overlap, and reappear over time. We propose STAM-ASR, Speaker-Temporal Anchoring with Memory, a lightweight framework that extends an already pretrained AudioLLM for multi-speaker ASR. Without relying on an external diarization system, STAM-ASR learns speaker activity and speaker-aware representations directly from intermediate AudioLLM features. Hence providing explicit who and when cues to modulate the AudioLLM's semantic representation without explicit speech separation. STAM-ASR further maintains fixed-size speaker and conversational memories to carry complementary context across turns. We evaluate STAM-ASR on AMI, ICSI, LibriCSS, and NOTSOFAR-1 across close-talk, far-field, overlapping, and cross-domain conditions. Our reported results shows that speaker-temporal conditioning and memory provide complementary benefits, while the gap between reference and predicted speaker activity identifies robust speaker tracking as a key remaining challenge.
Victor Tolulope Olufemi, Syeda Faiza Ahmed Sara, Shammur Absar Chowdhury
Qatar Computing Research Institute (QCRI), Doha, Qatar
Transcribing and understanding multi-speaker conversations requires speech recognition, speaker attribution, and timestamp localization. While speech LLMs excel at single-speaker tasks, multi-speaker scenarios remain challenging due to overlapping speech, backchannels, rapid turn-taking, and context window constraints. We propose Speaker-Reasoner, an end-to-end Speech LLM with agentic multi-turn temporal reasoning. Instead of single-pass inference, the model iteratively analyzes global audio structure, autonomously predicts temporal boundaries, and performs fine-grained segment analysis, jointly modeling speaker identity, gender, timestamps, and transcription. A speaker-aware cache further extends processing to audio exceeding the training context window. Trained with a three-stage progressive strategy, Speaker-Reasoner achieves consistent improvements over strong baselines on AliMeeting and AISHELL-4 datasets, particularly in handling overlapping speech and complex turn-taking.
Zhennan Lin, Shuai Wang, Zhaokai Sun +5
School of Intelligence Science and Technology, Nanjing University · Shanghai Lingguang Zhaxian Technology
We present TagSpeech, a unified LLM-based framework that utilizes Temporal Anchor Grounding for joint multi-speaker ASR and diarization. The framework is built on two key designs: (1) decoupled semantic and speaker streams fine-tuned via Serialized Output Training (SOT) to learn turn-taking dynamics; and (2) an interleaved time anchor mechanism that not only supports fine-grained timestamp prediction but also acts as a synchronization signal between semantic understanding and speaker tracking. Compared to previous works that primarily focus on speaker-attributed ASR or implicit diarization, TagSpeech addresses the challenge of fine-grained speaker-content alignment and explicitly models "who spoke what and when" in an end-to-end manner. Experiments on AMI and AliMeeting benchmarks demonstrate that our method achieves consistent improvements in Diarization Error Rate (DER) over strong end-to-end baselines, including Qwen-Omni and Gemini, particularly in handling complex speech overlaps. Moreover, TagSpeech employs a parameter-efficient training paradigm in which the LLM backbone is frozen and only lightweight projectors are trained, resulting in strong performance with low computational cost.
Mingyue Huo, Yiwen Shao, Yuheng Zhang
University of Illinois Urbana-Champaign · Johns Hopkins University