Parameter Details

Text

This is the text to be synthesized to audio.

VoiceId

• Dan: Young Male
• Will: Mature Male
• Scarlett: Young Female
• Liv: Young Female
• Amy: Mature Female

Bitrate

Defaults to 192k.

• Use lower values for low bandwidth or to reduce the transferred file size.
• Use higher values for higher fidelity.

Speed

Defaults to 0. Examples:

• 0.5: makes the audio 50% faster (i.e. 60-second audio becomes 42 seconds)
• -0.5: makes the audio 50% slower (i.e. 60-second audio becomes 90 seconds)

Pitch

Defaults to 1. However, on the landing page, we default male voices to 0.92 as people tend to prefer lower/deeper male voices.

Codec

Defaults to libmp3lame (MP3).

• Use pcm_mulaw for phone calls. pcm_s16le returns 22050 Hz raw audio.

Temperature

Defaults to 0.25.

• The lower values make audio deterministic and more stable.
• The higher values make audio more expressive and less-deterministic.
• With a high Temperature value, audio will be different every time. However, it also increases the probability of mispronunciation.

TimestampType

By default, the endpoint returns per-sentence timestamps. Use word to get per-word timestamps.

The timestamp feature is currently not supported via the /stream endpoint.

CallbackUrl

If provided, the server will POST a JSON body to the CallbackUrl. A sample body looks like below:

{  
   "TaskId": "8282b92d",  
   "TaskStatus": "completed", // or "failed"  
 }