Skip to content

Polly  >  Operations  >  synthesize_speech

synthesize_speech

Operation

synthesize_speech async 

synthesize_speech(input: SynthesizeSpeechInput, plugins: list[Plugin] | None = None) -> SynthesizeSpeechOutput

Synthesizes UTF-8 input, plain text or SSML, to a stream of bytes. SSML input must be valid, well-formed SSML. Some alphabets might not be available with all the voices (for example, Cyrillic might not be read at all by English voices) unless phoneme mapping is used. For more information, see How it Works.

Parameters:

Name Type Description Default
input SynthesizeSpeechInput

An instance of SynthesizeSpeechInput.

 required
plugins list[Plugin] | None

A list of callables that modify the configuration dynamically. Changes made by these plugins only apply for the duration of the operation execution and will not affect any other operation invocations.

 None

Returns:

Type Description
SynthesizeSpeechOutput

An instance of SynthesizeSpeechOutput.

Input

SynthesizeSpeechInput dataclass

Dataclass for SynthesizeSpeechInput structure.

Attributes

engine class-attribute instance-attribute 
engine: Engine | None = None

Specifies the engine (standard, neural, long-form, or generative) for Amazon Polly to use when processing input text for speech synthesis. Provide an engine that is supported by the voice you select. If you don't provide an engine, the standard engine is selected by default. If a chosen voice isn't supported by the standard engine, this will result in an error. For information on Amazon Polly voices and which voices are available for each engine, see Available Voices.

language_code class-attribute instance-attribute 
language_code: LanguageCode | None = None

Optional language code for the Synthesize Speech request. This is only necessary if using a bilingual voice, such as Aditi, which can be used for either Indian English (en-IN) or Hindi (hi-IN).

If a bilingual voice is used and no language code is specified, Amazon Polly uses the default language of the bilingual voice. The default language for any voice is the one returned by the DescribeVoices operation for the LanguageCode parameter. For example, if no language code is specified, Aditi will use Indian English rather than Hindi.

lexicon_names class-attribute instance-attribute 
lexicon_names: list[str] | None = None

List of one or more pronunciation lexicon names you want the service to apply during synthesis. Lexicons are applied only if the language of the lexicon is the same as the language of the voice. For information about storing lexicons, see PutLexicon.

output_format class-attribute instance-attribute 
output_format: OutputFormat | None = None

The format in which the returned output will be encoded. For audio stream, this will be mp3, ogg_vorbis, ogg_opus, mu-law, a-law or pcm. For speech marks, this will be json.

When pcm is used, the content returned is audio/pcm in a signed 16-bit, 1 channel (mono), little-endian format.

sample_rate class-attribute instance-attribute 
sample_rate: str | None = None

The audio frequency specified in Hz.

The valid values for mp3 and ogg_vorbis are "8000", "16000", "22050", "24000", "44100" and "48000". The default value for standard voices is "22050". The default value for neural voices is "24000". The default value for long-form voices is "24000". The default value for generative voices is "24000".

Valid values for pcm are "8000" and "16000" The default value is "16000".

Valid value for ogg_opus is "48000".

Valid value for mu-law and a-law is "8000".

speech_mark_types class-attribute instance-attribute 
speech_mark_types: list[SpeechMarkType] | None = None

The type of speech marks returned for the input text.

text class-attribute instance-attribute 
text: str | None = None

Input text to synthesize. If you specify ssml as the TextType, follow the SSML format for the input text.

text_type class-attribute instance-attribute 
text_type: TextType | None = None

Specifies whether the input text is plain text or SSML. The default value is plain text. For more information, see Using SSML.

voice_id class-attribute instance-attribute 
voice_id: VoiceId | None = None

Voice ID to use for the synthesis. You can get a list of available voice IDs by calling the DescribeVoices operation.

Output

SynthesizeSpeechOutput dataclass

Dataclass for SynthesizeSpeechOutput structure.

Attributes

audio_stream class-attribute instance-attribute 
audio_stream: StreamingBlob = b''

Stream containing the synthesized speech.

content_type class-attribute instance-attribute 
content_type: str | None = None

Specifies the type audio stream. This should reflect the OutputFormat parameter in your request.

  • If you request mp3 as the OutputFormat, the ContentType returned is audio/mpeg.

  • If you request ogg_vorbis as the OutputFormat, the ContentType returned is audio/ogg.

  • If you request ogg_opus as the OutputFormat, the ContentType returned is audio/ogg.

  • If you request pcm as the OutputFormat, the ContentType returned is audio/pcm in a signed 16-bit, 1 channel (mono), little-endian format.

  • If you request mu-law as the OutputFormat, the ContentType returned is audio/mulaw.

  • If you request a-law as the OutputFormat, the ContentType returned is audio/alaw.

  • If you request json as the OutputFormat, the ContentType returned is application/x-json-stream.

request_characters class-attribute instance-attribute 
request_characters: int = 0

Number of characters synthesized.