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Convert text into spoken audio. The output is a base64-encoded audio string that must be decoded before use.
**Available Models:**
- **bulbul:v3**: Latest model with improved quality, 30+ voices, and temperature control
- **bulbul:v2**: Legacy model with pitch and loudness controls
**Important Notes for bulbul:v3:**
- Pitch and loudness parameters are NOT supported
- Pace range: 0.5 to 2.0
- Preprocessing is automatically enabled
- Default sample rate is 24000 Hz
- Supports sample rates: 8000, 16000, 22050, 24000 Hz (REST API also supports 32000, 44100, 48000 Hz)
Convert text into spoken audio. The output is a base64-encoded audio string that must be decoded before use.
Available Models:
bulbul:v3: Latest model with improved quality, 30+ voices, and temperature control
bulbul:v2: Legacy model with pitch and loudness controls
Important Notes for bulbul:v3:
Pitch and loudness parameters are NOT supported
Pace range: 0.5 to 2.0
Preprocessing is automatically enabled
Default sample rate is 24000 Hz
Supports sample rates: 8000, 16000, 22050, 24000 Hz (REST API also supports 32000, 44100, 48000 Hz)
Authentication
api-subscription-keystring
API Key authentication via header
Request
This endpoint expects an object.
textstringRequired
The text(s) to be converted into speech.
Features:
Supports code-mixed text (English and Indic languages)
Model-specific limits:
bulbul:v3: Max 2500 characters
bulbul:v2: Max 1500 characters
Important Note:
For numbers larger than 4 digits, use commas (e.g., ‘10,000’ instead of ‘10000’)
This ensures proper pronunciation as a whole number
target_language_codeenumRequired
The language code in BCP-47 format.
speakerenum or nullOptionalDefaults to shubh
The speaker voice to be used for the output audio.
Note: Speaker selection must match the chosen model version.
Important: Speaker names are case-sensitive and must be lowercase (e.g., ritu not Ritu).
pitchdouble or nullOptional
Controls the pitch of the audio. Lower values result in a deeper voice, while higher values make it sharper. The suitable range is between -0.75 and 0.75. Default is 0.0.
Note: This parameter is only supported for bulbul:v2. It is NOT supported for bulbul:v3.
pacedouble or nullOptional0.3-3Defaults to 1
Controls the speed of the audio. Lower values result in slower speech, while higher values make it faster. Default is 1.0.
Model-specific ranges:
bulbul:v3: 0.5 to 2.0
bulbul:v2: 0.3 to 3.0
loudnessdouble or nullOptional0.1-3
Controls the loudness of the audio. Lower values result in quieter audio, while higher values make it louder. The suitable range is between 0.3 and 3.0. Default is 1.0.
Note: This parameter is only supported for bulbul:v2. It is NOT supported for bulbul:v3.
speech_sample_rateenum or nullOptionalDefaults to 22050
Specifies the sample rate of the output audio. Supported values are 8000, 16000, 22050, 24000, 32000, 44100, 48000 Hz.
Note: Higher sample rates (32000, 44100, 48000 Hz) are only available with bulbul:v3 via the REST API, not in streaming mode.
Default: 24000 Hz
enable_preprocessingbooleanOptionalDefaults to false
Controls whether normalization of English words and numeric entities (e.g., numbers, dates) is performed. Set to true for better handling of mixed-language text.
Model-specific behavior:
bulbul:v3: Not Supported
bulbul:v2: Default is false
modelenumOptional
Specifies the model to use for text-to-speech conversion.
Available models:
bulbul:v3: Latest model with improved quality, 30+ voices, pace, and temperature control
bulbul:v2: Legacy model with pitch, loudness, and pace controls
Allowed values:
output_audio_codecenum or nullOptionalDefaults to wav
Specifies the audio codec for the output audio file. Different codecs offer various compression and quality characteristics.
temperaturedouble or nullOptional0.01-2Defaults to 0.6
Temperature controls how much randomness and expressiveness the TTS model uses while generating speech.
Lower values produce more stable and consistent output, while higher values sound more expressive but may introduce artifacts or errors. The suitable range is between 0.01 and 2.0. Default is 0.6.
Note: This parameter is only supported for bulbul:v3. It has no effect on bulbul:v2.
dict_idstring or nullOptional
The ID of a pronunciation dictionary to apply during synthesis. When provided, matching words in the input text will be replaced with their custom pronunciations before generating speech.
