Multilingual support

[Kostis-S-Z]

What's changing

The overall goal of this PR is to add support for more languages.

In the process, the following changes / additions were made:

• Add unified TTS model interface to hide away complexity of the different tts models: TTSModel
• Create registry for tts model loading functions: TTS_LOADERS
• Create registry for tts model inference functions: TTS_INFERENCE
• Validate config.yaml's text_to_speech_model with validate_text_to_speech_model
• Re-write test_load_tts_model to use parametrization

Closes #29

How to test it

Steps to test the changes:

1. Clone the repository: git clone https://github.com/Kostis-S-Z/document-to-podcast.git
2. Move to the directory: cd document-to-podcast
3. Change branch: git checkout multilingual-support
4. Install the package: pip install -e .
5. Pick a model and languages from the list below (under Model IDs / Languages tested:)
6. Edit example_data/config.yaml (or create a copy) and change

• input_file: Use a file that has text in a language of your choice
• text_to_speech_model: Use one of the model ids, defined below, based on the language you are testing
• text_to_text_prompt: Re-write it / Translate it in the testing language
• speaker/description: Re-write it / Translate it in the testing language
• voice_profile: Use one of the pre-defined profiles based on the testing language, from the list below

7. document-to-podcast --from_config example_data/config.yaml
8. If you don't want to wait for the whole podcast to be generated you can stop it mid-way, by pressing Ctrl+C in the terminal that you are running the process. It will stop and save the script and audio up until that point!
9. Verify by checking podcast.txt and podcast.wav

Model IDs / Languages tested:

• parler-tts/parler-tts-mini-multilingual-v1.1
  • Portuguese ( Sophia & Nicholas)
  • Dutch ( Mark & Jessica)
  • French ( Daniel & Christine)
  • German ( Nicole & Michelle)
  • Italian ( Julia & Richard)
  • Polish ( Alex & Natalie)
  • Spanish ( Steven & Olivia)
• ai4bharat/indic-parler-tts
  • Hindi ( Rohit & Divya)
  • Telugu ( Prakash & Lalitha)
• suno/bark
  • Spanish ( v2/es_speaker_0 & v2/es_speaker_8)
• OuteTTS-0.2-500M
  • Korean (female_1 & male_1)

Additional notes for reviewers

Its expected that some languages will work better than others. Its also a common issue that the voice pattern might not be consistent across the speaker rounds (maybe Speaker 1 at first sound in one way, and then their voice might change)

I already...

• Tested the changes in a working environment to ensure they work as expected
• Added some tests for any new functionality
• Updated the documentation (both comments in code and under /docs)

[daavoo]

Not sure if we want to add multiple configs here, I guess is a discussion to have with the developer hub. All these seem like potential "Use Case" / "Customization" examples