Open TTS Leaderboard: Scalable Evaluation for Multilingual Text-to-Speech and Voice Cloning

Introduces the Open TTS Leaderboard, a new system for evaluating TTS and voice cloning models using objective metrics: WER/CER for intelligibility (via Qwen3 ASR), RTFx/TTFA for speed (on H200 GPU and CPU), and cosine similarity for speaker similarity (via WavLM embeddings). The leaderboard supports multilingual evaluation and includes a 'Listen' tab for direct comparison of model outputs and a 'Streaming' tab for TTFA analysis. It aims to address the scalability limitations of human preference-based leaderboards and increase the visibility of open-source TTS models.