BUT System for the MLC-SLM Challenge
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26230%2F26%3A0199410" target="_blank" >RIV/00216305:26230/26:0199410 - isvavai.cz</a>
Result on the web
<a href="https://www.isca-archive.org/mlcslm_2025/polok25_mlcslm.pdf" target="_blank" >https://www.isca-archive.org/mlcslm_2025/polok25_mlcslm.pdf</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.21437/mlcslm.2025-6" target="_blank" >10.21437/mlcslm.2025-6</a>
Alternative languages
Result language
angličtina
Original language name
BUT System for the MLC-SLM Challenge
Original language description
We present a two-speaker automatic speech recognition (ASR) system that combines DiCoW—a diarization-conditioned variant of Whisper—with DiariZen, a diarization pipeline built on top of Pyannote. We first evaluate both systems in out-of-domain (OOD) multilingual scenarios without any fine-tuning. In this scenario, DiariZen consistently outperforms the baseline Pyannote diarization model, demonstrating strong generalization. Despite being fine-tuned on English-only data for target-speaker ASR, DiCoW retains solid multilingual performance,indicating that encoder modifications preserve Whisper’s multilingual capabilities. We then fine-tune both DiCoW and DiariZen on the MLC-SLM challenge data. The fine-tuned DiariZen continues to outperform the fine-tuned Pyannote baseline, while DiCoW sees further gains from domain adaptation. Our final system achieves a micro-average tcpWER/CER of 16.75 % and ranks second in Task 2 of the MLC-SLM challenge. Lastly, we identify several labeling inconsistencies in the training data—such as missing speech segments and incorrect silence annotations—which can hinder diarization fine-tuning. We propose simple mitigation strategies to address these issues and improve system robustness.
Czech name
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Czech description
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Classification
Type
O - Miscellaneous
CEP classification
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OECD FORD branch
10201 - Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8)
Result continuities
Project
Result was created during the realization of more than one project. More information in the Projects tab.
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů