TaDiCodec:
Text-aware Diffusion Speech Tokenizer for Speech Language Modeling
Abstract Speech tokenizers serve as foundational components for speech language models, yet current designs exhibit several limitations, including: (1) dependence on multi-layer residual vector quantization structures or high frame rates, (2) reliance on auxiliary pre-trained models for semantic distillation, and (3) requirements for complex two-stage training processes. In this work, we introduce the Text-aware Diffusion Transformer Speech Codec (TaDiCodec), a novel approach designed to overcome these challenges. TaDiCodec employs end-to-end optimization for quantization and reconstruction through a diffusion autoencoder, while integrating text guidance into the diffusion decoder to enhance reconstruction quality and achieve optimal compression. TaDiCodec achieves an extremely low frame rate of 6.25 Hz and a corresponding bitrate of 0.0875 kbps with a single-layer codebook for 24 kHz speech, while maintaining superior performance on critical speech generation evaluation metrics such as Word Error Rate (WER), speaker similarity (SIM), and speech quality (UTMOS). Notably, TaDiCodec employs a single-stage, end-to-end training paradigm, obviating the need for auxiliary pre-trained models. We also validate the compatibility of TaDiCodec in language model based zero-shot text-to-speech with both autoregressive modeling and masked generative modeling, demonstrating its effectiveness and efficiency for speech language modeling, as well as a significantly small reconstruction-generation gap. We will open source our code and model checkpoints.
This page is for research demonstration purposes only.
Figure 1: Comparison between TaDiCodec and other speech tokenizers. We use a three-dimensional coordinate system to display the performance across three dimensions: the x-axis represents WER, the y-axis represents UTMOS, and the z-axis represents SIM. The size of the markers is proportional to the kbps value.
Speech Reconstruction Comparison with Other Systems
This section compares the speech reconstruction quality of various systems with different bitrates.
Ground Truth | Mimi (1.1 kbps) | WavTokenizer (0.9 kbps) | BiCodec (0.65 kbps) | DualCodec (0.925 kbps) | Ours (0.0875 kbps) |
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In-the-Wild, EN | |||||
In-the-Wild, ZH | |||||
Singing | |||||
Zero-Shot TTS
This section demonstrates the zero-shot TTS capabilities built on TaDiCodec, showcasing various case types including articulatory, cross-lingual, and code-switching scenarios.
Case Type | Target Text | Prompt Speech | Generated Speech |
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Regular |
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Code-Switching |
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Cross-lingual |
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Articulatory |
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