Vāgdhenu: Open-source meter-aware text-to-speech for Sanskrit

Vāgdhenu, an open-source meter-aware text-to-speech system for Sanskrit, automatically detects verse meters and generates chant recitations. Developed by retraining a flow-matching TTS backbone on a custom 5-hour Sanskrit chant corpus, it achieves an expert MOS of 4.6 and correctly renders complex conjuncts. The system has produced two large-scale corpora: the Mahābhārata Tātparya Nirṇaya (5,183 verses) and the Śrīmad Bhāgavatam (~18,000 verses).

Paste a Sanskrit verse in any Indian script — the meter is detected automatically. First chant takes ~10–60s while the model warms up. If the demo doesn't load, use the backup demo ↗ https://prathoshap-vagdhenu-demo.hf.space? theme=light . Six vṛttas rendered by this system — including verses from the shipped deployments. Vāgdhenu maps a metrical verse to its chanted pārāyaṇa recitation. Its voice is a flow-matching TTS backbone retrained on a purpose-recorded, carefully designed single-speaker Sanskrit chant corpus ~5 hours , with a further voice-steering retrain; the neural vocoder is likewise fine-tuned for the chant register. Around the trained model sits the machinery a faithful Sanskrit chant pipeline needs: a script-aware frontend that routes Sanskrit through Kannada orthography avoiding the Hindi schwa-deletion that Devanagari triggers ; visarga sandhi with the jihvāmūlīya and upadhmānīya allophones; the aspiration contrast; the three sibilants and the full retroflex series kept distinct; homorganic anusvāra and vocalic ṝ; and a vṛtta-aware mechanism that detects the meter and selects a matched reference under the half-reference rule . The retrained model reaches an expert MOS of about 4.6 , and dense conjuncts — including retroflex aspirates — render correctly, the class earlier architectures could not crack. This system produced two corpora at scale. ● Mahābhārata Tātparya Nirṇaya — 32 chapters, 5,183 verses ~17.5h · video series ↗ https://www.youtube.com/playlist?list=PLL1s8qiaGy0IP0G PhlwaGA5EOfzoKrV ● Śrīmad Bhāgavatam — ~18,000 verses across 12 books · karaoke-video series ↗ https://www.youtube.com/playlist?list=PLDiYyVdyo2Sc