Doubao TTS

Requires DOUBAO_SPEECH_API_KEY in .env. Set DOUBAO_SPEECH_VOICE_TYPE for the default voice, or pass voice_id to the tool.

Current API

Use the new-console API key flow:

X-Api-Key: ${DOUBAO_SPEECH_API_KEY}
X-Api-Resource-Id: seed-tts-2.0

Do not use X-Api-App-Id and X-Api-Access-Key with a new-console API Key. If the API returns load grant: requested grant not found, the key type or auth header is probably wrong.

For long-form video narration, prefer the async endpoint:

POST https://openspeech.bytedance.com/api/v3/tts/submit
POST https://openspeech.bytedance.com/api/v3/tts/query

This returns audio_url plus sentences[].words[] timing metadata that can be used to build subtitles.

OpenMontage Usage

Generate with the TTS selector:

from tools.audio.tts_selector import TTSSelector

result = TTSSelector().execute({
    "preferred_provider": "doubao",
    "text": "如果 AI 真的会改变未来，普通人到底该怎么参与？",
    "voice_id": "zh_female_vv_uranus_bigtts",
    "output_path": "projects/my-video/assets/audio/narration.mp3",
    "speech_rate": 0,
    "enable_timestamp": True,
})

Or call the provider directly:

from tools.audio.doubao_tts import DoubaoTTS

result = DoubaoTTS().execute({
    "text": "短样本试听文本。",
    "voice_id": "zh_female_vv_uranus_bigtts",
    "output_path": "projects/my-video/assets/audio/doubao_sample.mp3",
})

The provider writes:

• output_path: downloaded audio file
• metadata_path: full query response JSON, defaulting to <output_path>.json

Recommended Workflow

1. Generate a 10-15 second sample before a full paid narration.
2. Ask the user to approve voice naturalness, accent, and speed.
3. Generate the full narration only after approval.
4. Keep the query JSON. It is the source of truth for subtitle timing.
5. Build captions from sentences[].words[], not from estimated text length.
6. Group captions by Chinese semantic phrases before applying timestamps. Do not split only by fixed character count; it can break phrases like "在不押单个公司的情况下" or "可能会被慢慢稀释" and hurt comprehension.
7. Let the video duration follow the approved voice rhythm unless the user explicitly asks to match a prior runtime.

Parameters

• voice_id: Doubao speaker / voice type. Defaults to DOUBAO_SPEECH_VOICE_TYPE.
• resource_id: use seed-tts-2.0 for Doubao Speech 2.0 voices.
• speech_rate: 0 is normal, 100 is 2x, -50 is 0.5x.
• sample_rate: default 24000.
• enable_timestamp: default true.
• return_usage: default true, requests usage metadata when available.

Do not pass additions.explicit_language by default. Some endpoint/key combinations reject zh-cn with unsupported additions explicit language zh-cn.

For calm Mandarin explainers, start with speech_rate: 0. If the result is too long for the approved format, make a short comparison sample with speech_rate: 25 or 50 before regenerating the full narration. Do not speed up only to match a previous provider's duration if the user prefers Doubao's natural pace.

Troubleshooting

• load grant: requested grant not found: wrong key type or wrong auth header. Use X-Api-Key for new-console API Keys.
• speaker permission denied: voice id is wrong or not authorized for the selected resource.
• quota exceeded: quota, lifetime characters, or concurrency exceeded.
• Missing timestamps: verify enable_timestamp: true, keep the query JSON, and confirm the selected endpoint returned sentences.

Safety

Never print or write the API key to logs, metadata, patches, or project artifacts. .env.example should contain only empty variable names.