Guide 6: Troubleshooting and Resources
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This guide provides solutions for common issues encountered during the TTS data preparation, training, and inference process, along with a list of useful tools and resources.
8. Troubleshooting Common Issues
Refer to this table when you encounter problems. Issues often trace back to data quality or configuration settings.
Problem Category | Specific Issue | Possible Causes & Solutions | Relevant Guide(s) |
---|---|---|---|
Data Preparation | Script errors during chunking/normalization | Incorrect file paths; unsupported audio format initially; missing dependencies (ffmpeg , pydub ); extremely noisy/silent audio confusing silence detection. Check script paths, install dependencies, adjust silence parameters. |
1_DATA_PREPARATION.md |
Manifest generation skips many files | Mismatched filenames between audio and transcripts; empty transcript files; incorrect paths specified in the script; non-UTF8 encoding in text files. Verify naming, check paths, ensure text files have content & UTF-8 encoding. | 1_DATA_PREPARATION.md | |
Training Setup | pip install fails |
Missing system libraries (e.g., libsndfile-dev ); incompatible Python version; network issues; conflicts between packages. Read error messages carefully, install system libs, use virtual env, check framework docs for prerequisites. |
2_TRAINING_SETUP.md |
PyTorch cuda is not available |
Incorrect PyTorch version installed (CPU-only); incompatible NVIDIA driver/CUDA toolkit version; GPU not detected by OS. Reinstall PyTorch with correct CUDA version from official site, update drivers. | 2_TRAINING_SETUP.md | |
Training Execution | CUDA Out-of-Memory (OOM) error at start/during train | batch_size too large for GPU VRAM; model architecture too complex; memory leak in framework/custom code. Reduce batch_size in config; enable Automatic Mixed Precision (AMP/FP16) if available; check for framework updates. |
2_TRAINING_SETUP.md, 3_MODEL_TRAINING.md |
Training Loss is NaN or diverges (explodes) |
Learning rate too high; unstable gradients; bad data batch (e.g., corrupted audio/text); numerical precision issues. Lower learning rate; check data quality; use gradient clipping (often enabled by default); try FP32 if using AMP/FP16. | 2_TRAINING_SETUP.md, 3_MODEL_TRAINING.md | |
Training Loss stagnates (doesn’t decrease) | Learning rate too low; poor data quality/variety; model stuck in local minimum; incorrect model configuration. Increase learning rate slightly; improve/augment data; check config (esp. audio params); try different optimizer. | 1_DATA_PREPARATION.md, 2_TRAINING_SETUP.md, 3_MODEL_TRAINING.md | |
Validation Loss increases while Training Loss decreases (Overfitting) | Model memorizing training data; insufficient/unrepresentative validation set; training for too long. Stop training early (based on best val loss); add more diverse training data; use regularization (weight decay, dropout - check config); improve validation set. | 1_DATA_PREPARATION.md, 3_MODEL_TRAINING.md | |
Inference Quality | Output sounds robotic/monotonic | Insufficient training; poor prosody in training data; model architecture limitations; text normalization issues. Train longer; improve data variety/quality; try different model architecture; ensure text is punctuated/normalized well. | 1_DATA_PREPARATION.md, 3_MODEL_TRAINING.md, 4_INFERENCE.md |
Output is noisy/garbled/unintelligible | Bad data quality (noise baked in); model didn’t converge; mismatch between training config and inference config/checkpoint; incorrect sampling rate used in inference. Clean training data rigorously; train longer; ensure EXACT config/checkpoint match; verify audio parameters. | All Guides | |
Output sounds like the wrong speaker (fine-tuning) | Pre-trained model not loaded correctly; learning rate too high initially; insufficient fine-tuning data/steps; speaker ID mismatch. Verify pretrained_model_path and ignore_layers in config; use lower LR for fine-tuning; train longer; check speaker ID. |
2_TRAINING_SETUP.md, 3_MODEL_TRAINING.md, 4_INFERENCE.md | |
Inference cuts off early or speaks too fast/slow | Model limitation (duration prediction); inference setting limiting max output length; length scale/speed parameter incorrect. Check framework docs for max decoder steps / max length settings; adjust speed control parameters. | 4_INFERENCE.md | |
Model Usage | Cannot load checkpoint file | Corrupted download/file; using checkpoint with incompatible framework version or config file; incorrect file path. Re-download/verify file integrity; use the correct config; ensure framework version matches the one used for training; check path. | 5_PACKAGING_AND_SHARING.md, 4_INFERENCE.md |
10. Useful Resources & Tools
This list includes software, libraries, and communities helpful for TTS projects.
Audio Processing & Analysis:
- Audacity: Free, open-source, cross-platform audio editor. Excellent for manual inspection, cleaning, labeling, and basic processing of audio files.
- FFmpeg: The swiss-army knife command-line tool for audio/video conversion, resampling, channel manipulation, format changes, and much more. Essential for scripting batch operations.
- SoX (Sound eXchange Compiled) or Sox - Source Code: Command-line utility for audio processing. Useful for effects, format conversion, and getting audio information (
soxi
command). - pydub: Python library for easy audio manipulation (slicing, format conversion, volume adjustment, silence detection). Uses ffmpeg/libav backend.
- librosa: Python library for advanced audio analysis, feature extraction (like Mel spectrograms), and visualization. Often used internally by TTS frameworks.
- soundfile: Python library for reading/writing audio files, based on libsndfile. Supports many formats.
- pyloudnorm: Python library for loudness normalization (LUFS), generally preferred over simple peak normalization for perceived consistency.
Transcription (ASR):
- OpenAI Whisper: High-quality open-source ASR model, supports many languages. Good baseline, but punctuation often needs review. Can run locally (GPU recommended) or via API. Various community implementations exist.
- Google Gemini Models (via API/AI Studio): Capable models for transcription, often perform well on clear audio, potentially best on pre-chunked segments. Check API/Studio for current capabilities and pricing/free tiers.
- Cloud ASR Services:
- Google Cloud Speech-to-Text
- AWS Transcribe
- Azure Speech Service
- Often reliable, pay-as-you-go, may have initial free quotas.
- Hugging Face Transformers - ASR Models: Hub for many pre-trained ASR models, including fine-tuned versions of Whisper and others. Explore models fine-tuned for specific languages or punctuation improvement.
- ElevenLabs Speech To Text (Scribe): Commercial Service. Known for very high accuracy in both transcription and punctuation, but is a paid service and can be relatively expensive compared to others. Worth considering if budget allows and maximum out-of-the-box accuracy is required.
TTS Frameworks & Codebases (Examples - Check for active forks/successors):
- StyleTTS2 (Research Repo): Influential work on style control. Look for actively maintained forks that have implemented training/inference pipelines.
- VITS (Research Repo): Popular end-to-end architecture. Many forks and implementations exist.
- Coqui TTS (Archived): Was a very popular and comprehensive library. Although archived, its codebase and concepts remain influential. Many active forks might exist.
- ESPnet: End-to-end speech processing toolkit, including TTS recipes for various models. More research-oriented.
- Search GitHub: Use keywords like “TTS”, “VITS training”, “StyleTTS2 training”, “PyTorch TTS” to find current projects.
Python Environment & Deep Learning:
- Python: The core programming language.
- PyTorch: The primary deep learning library used by most modern TTS frameworks.
- TensorBoard: Essential for visualizing training progress (works with PyTorch too).
- pip / uv: Python package installers.
uv
is a newer, often much faster alternative. - conda / venv: Tools for creating isolated Python environments.
- Git: Version control system, essential for cloning repositories and managing code.
- Hugging Face Hub: Platform for sharing models (including TTS), datasets, and code.
Communities:
- TTS Framework GitHub Discussions/Issues: Check the specific repository you are using for community questions and answers.
- Discord Servers: Many AI/ML communities (like LAION, EleutherAI, specific framework servers) have channels dedicated to TTS.
- Reddit: Subreddits like r/SpeechSynthesis, r/MachineLearning.
This concludes the main series of guides. Remember that building good TTS models often involves iteration – revisiting data preparation or adjusting training parameters based on results is common practice. Good luck!
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