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Introduction

Welcome to the iSpeech Inc. Application Programming Interface (API) Developer Guide. This guide describes the available variables, commands, and interfaces that make up the iSpeech API.

The iSpeech API allows developers to implement Text-To-Speech (TTS) and Automated Voice Recognition (ASR) in any Internet-enabled application.

The API’s are platform agnostic which means any device that can record or play audio that is connected to the Internet can use the iSpeech API.

Minimum Requirements

Below are the minimum requirements needed to use the iSpeech API. The API can be use with and without a software development kit (SDK).

Internet Connection

iSpeech services require an Internet connection.

HTTP Protocol

The iSpeech API follows the HTTP standard by using GET and POST. Some web browsers limit the length of GET requests to a few thousand characters.

Request/Responses

Requests can be in URL-encoded, JSON, or XML data formats. You can specify the output data format of responses. For TTS, binary data is usually returned if the request is successful. For speech recognition, URL-encoded text, JSON, or XML can be returned by setting the output variable.

API Key

An API key is a password that is required for access. To obtain an API key please visit: https://www.ispeech.org/developers and register for a developer account.

API Features

You can retrieve the properties of your API keys. Key information includes a voice list, amount of credits, locales, and many other parameters.

Text to Speech

You can synthesize spoken audio through iSpeech TTS in a variety of voices, formats, bitrates, frequencies, and playback speeds. Math markup language (MathML) and Speech synthesis markup language (SSML) are also supported.

Automated Speech Recognition

You can convert spoken audio to text using a variety of languages and recognition models. We can create custom recognition models to improve recognition quality.

Position Markers

You can get the position in time when words are spoken in TTS audio.

Visemes

You can get the position in time of mouth positions when words are spoken in TTS audio.

Developer Support

Sales

Automated purchasing system: https://www.ispeech.org/developer/purchase/ iSpeech sales can be contacted at the following phone number: +1-917-338-7723 from 10 AM to 6 PM Eastern Time, Monday to Friday. You can also email sales@ispeech.org.

Support / Troubleshooting

Please contact our support team at support@ispeech.org .

Software Development Kits

iSpeech SDKs simplify the iSpeech API. You should use iSpeech SDKs if the option is available. Only mobile SDKs made by iSpeech allow you to use the iSpeech API for free.

Availability

iPhone, Android, BlackBerry, .NET, Java (Server), PHP, Flash, Javascript/Flash, Ruby, Python, Perl

API Access Pricing

Platforms Price
iPhone, Android, BlackBerry Free with fair usage using iSpeech SDK for non-revenue generating apps. Apps must follow the iSpeech standard usage guidelines for branding.
.NET, Java, PHP, Flash, Ruby, Python, Perl Between $0.05 and $0.0001 per word (TTS) or transaction (ASR), depending on quantity

Authentication

API Key

API Key Information Retrieval

curl "https://api.ispeech.org/api/rest?apikey=**YOUR_KEY_HERE**
&action=information&output=rest"

HTTP Response

[…]&voice-locale-94-1=ja&voice-locale-94-2=ja-jp&voice-gender-94=female
&voice-description-94=Japanese+Female+Voice&wordlimit=40&model=assistant%2cdate
%2cnfl%2cnba%2cusmoney%2cmlb%2cnumbersto9%2cnumbersto99%2cnumbersto999%2ctime
%2cphonenumber%2cstreets%2csportsteam%2ccitystate&credits=5672606&unlimited=enabled
&alias=enabled&asr-sms=enabled&asr-voicemail=enabled&asr-dictation=enabled

An API key is a password that is required for access. To obtain an API key please visit: https://www.ispeech.org/developers and register for a developer account.

View/Edit Keys

Manage your API keys by using the iSpeech developer website . You can request additional features for your API keys on that website.

Request Parameter Reference

Parameter Data Type Example Value
Apikey 32 character hex integer YOUR_KEY_HERE

Transaction Types

The iSpeech API supports URL Encoded, XML, and JSON formats.

Supported transaction types

Transaction Type Input Format URL
HTTP GET/POST URL Encoded https://api.ispeech.org/api/rest
HTTP GET/POST XML https://api.ispeech.org/api/xml
HTTP GET/POST JSON https://api.ispeech.org/api/json

Request Parameters

Parameter Supported Values
output (optional) xml, json, rest (default)

Text to Speech

Example HTTP GET Request (Using most variables)

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &voice=usenglishfemale
      &format=mp3
      &frequency=44100
      &bitrate=128
      &speed=1
      &startpadding=1
      &endpadding=1
      &pitch=110
      &filename=myaudiofile"

The iSpeech Text-To-Speech API allows you to synthesize high-quality spoken audio in multiple formats. The iSpeech API doesn’t use callbacks because it’s fast and synchronous. You’ll always receive audio data or an error message in the same HTTP transaction.

Request Parameters

Parameter Data Type Example Value
Action String convert, ssml
Text String Hello World
Ssml (optional) String <?xml version=”1.0” ?><speak version= […]
Voice (optional) String usenglishfemale (default)
Format (optional) String mp3 (default)
Frequency (optional) Integer (hertz) 16000 (default)
Bitrate (optional) Integer (kbps) 48 (default)
Speed (optional) Integer -10 to 10 (default: 0)
Startpadding (optional) Integer (seconds) 5 (default: 0)
Endpadding (optional) Integer (seconds) 5 (default: 0)
Pitch (optional) Integer 0 to 200 (default: 100)
Bitdepth (optional) Integer (bits per sample) 8 or 16 (default: 16)
Filename (optional) String myaudio or myaudio.mp3 (default: rest.*)
Library (optional) String libmath

Voices - Standard

HTTP GET Request (Setting voice to European French Female)

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &format=mp3
      &voice=eurfrenchfemale"
Name Alias
US English Female (default) usenglishfemale
US English Male usenglishmale
UK English Female ukenglishfemale
UK English Male ukenglishmale
Australian English Female auenglishfemale
US Spanish Female usspanishfemale
US Spanish Male usspanishmale
Chinese Female chchinesefemale
Chinese Male chchinesemale
Hong Kong Cantonese Female hkchinesefemale
Taiwan Chinese Female twchinesefemale
Japanese Female jpjapanesefemale
Japanese Male jpjapanesemale
Korean Female krkoreanfemale
Korean Male krkoreanmale
Canadian English Female caenglishfemale
Hungarian Female huhungarianfemale
Brazilian Portuguese Female brportuguesefemale
European Portuguese Female eurportuguesefemale
European Portuguese Male eurportuguesemale
European Spanish Female eurspanishfemale
European Spanish Male eurspanishmale
European Catalan Female eurcatalanfemale
European Czech Female eurczechfemale
European Danish Female eurdanishfemale
European Finnish Female eurfinnishfemale
European French Female eurfrenchfemale
European French Male eurfrenchmale
European Norwegian Female eurnorwegianfemale
European Dutch Female eurdutchfemale
European Polish Female eurpolishfemale
European Italian Female euritalianfemale
European Italian Male euritalianmale
European Turkish Female eurturkishfemale
European Turkish Male eurturkishmale
European German Female eurgermanfemale
European German Male eurgermanmale
Russian Female rurussianfemale
Russian Male rurussianmale
Swedish Female swswedishfemale
Canadian French Female cafrenchfemale
Canadian French Male cafrenchmale
Arabic Male ararabicmale

Voices - Custom

Custom Voices may be enabled for your account. They can be found in the developer portal -> api key properties -> custom voices. You can use them by setting the variable voice to the custom alias.

Name Alias
President Obama Obama (voice=obama)
Custom Voice customvoice1 (voice=customvoice1)

Voices - List Retrieval

HTTP GET Network Transaction to get XML voice list.

curl "https://api.ispeech.org/api/rest?action=information&output=xml"

XML Response

<?xml version='1.0'?>
<data>
    <result>success</result>
    <voice-1>krkoreanfemale</voice-1>
    <voice-locale-1-1>ko-kr</voice-locale-1-1>
    <voice-locale-1-2>ko</voice-locale-1-2>
    <voice-gender-1>female</voice-gender-1>
    <voice-description-1>Korean Female Voice</voice-description-1>
    <voice-2>usenglishfemale</voice-2>
    <voice-locale-2-1>en-us</voice-locale-2-1>
    <voice-locale-2-2>en</voice-locale-2-2>
    <voice-gender-2>female</voice-gender-2>
    <voice-description-2>United States English Female Voice</voice-description-2>
</data>

JSON Response

{"voice-gender-48":"female","voice-locale-22-1":"fr-ca","voice-locale-8-1":"pt-br","voice-description-2":"Finnish Female Voice","voice-description-3":"Hong Kong Chinese Male Voice","voice-58":"eurdanishfemale","voice-description-1":"Korean Female Voice","voice-description-6":"Chinese Female Voice","voice-description-7":"United Kingdom English Female Voice"}

REST / URL Encoded Response

curl "https://api.ispeech.org/api/rest?result=success
      &voice-1=krkoreanfemale2
      &voice-locale-1-1=ko-kr
      &voice-gender-1=female
      &voice-description-1=Korean+Female+Voice
      &voice-2=eurfinnishfemale
      &voice-locale-2-1=fi-fi
      &voice-gender-2=female
      &voice-description-2=Finnish+Female+Voice
      &voice-3=chchinesemale1
      &voice-locale-3-1=zh
      &voice-locale-3-2=zh-hk
      &[...more voices...]"

A current list of voices that are enabled for an API key can be retrieved in REST, JSON, and XML format by using the following service. HTTP GET and POST are supported. A web browser or a REST client can be used to make these HTTP requests.

Speed

HTTP GET Request (Setting speed to 5)

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &voice=usenglishfemale
      &format=mp3
      &speed=5"

Most voices support speed controls.

Speed Value (Integer)
Fastest 10
Faster Speed > 0
Normal (default) 0
Slower Speed < 0
Slowest -10

Bitrates

HTTP GET Request (Setting bitrate to 16 kilobits per second)

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &voice=usenglishfemale
      &format=mp3
      &bitrate=16"

Note: Bitrates can only be selected for MP3s.

Valid values are 16, 24, 32, 48 (default), 56, 64, 80, 96, 112, 128, 144, 160, 192, 224, 256, or 320. Bitrates are listed in kilobits per second.

Formats

Example HTTP GET Request (Setting format to wav)

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &voice=usenglishfemale
      &format=wav"
Name Extension
Audio Interchange File Format aiff
MPEG Layer 3 (default) mp3
Ogg Vorbis ogg
Windows Media Audio wma
Free Lossless Audio Codec flac
Wave PCM wav
Wave (alaw) alaw
Wave (µ-law) ulaw
Dialogic ADPCM vox
MPEG-4 mp4

Frequencies

Example HTTP GET Request (Setting frequency to 16000 Hz)

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &voice=usenglishfemale
      &frequency=16000"

Possible values: 8000, 11025, 16000 (default), 22050, 24000, 32000, 44100, 48000 cycles per second (Hertz)

Padding

Padding adds silence to a section of the audio file.

Start Padding

Example HTTP GET Request (Setting start padding to 3 seconds)

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &voice=usenglishfemale
      &startpadding=3"

Adds a period of silence to the beginning of the audio file.

End Padding

Example HTTP GET Request (Setting end padding to 3 seconds)

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &voice=usenglishfemale
      &endpadding=3"

Adds a period of silence to the beginning of the audio file.

Pitch

Example HTTP GET Request (Setting pitch to 50)

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &voice=usenglishfemale
      &pitch=50"

Possible values: 0 to 200 (integer), 0 is lowest pitch, 100 is default, 200 is highest pitch. Pitch is enabled only on some voices.

Bit Depth

Example HTTP GET Request (Setting bit depth to 8)

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &voice=usenglishfemale
      &format=wav
      &bitdepth=8"

The bit depth is amount of audio detail for each audio sample.

Possible values are 8 and 16 (default) bits/sample on AIFF, FLAC, and WAVE file formats.

Filename

Example HTTP GET Request (Setting filename of audio)

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &voice=usenglishfemale
      &format=wav
      &filename=myaudiofile"

The filename is the name of the audio file that will download. Specifying the extension is optional. If the extension is missing, the correct extension will be added automatically. The default is rest.[extension], for example: rest.mp3.

Speech Synthesis Markup Language (SSML)

Example HTTP GET Request (Emphasis added on the word big)

curl "https://api.ispeech.org/api/rest?
      action=ssml&ssml=%3C%3Fxml%20version%3D%221.0%22%3F%3E%3Cspeak
      %20version%3D%221.0%22%20xmlns%3D%22http%3A%2F%2Fwww.w3.org
      %2F2001%2F10%2Fsynthesis%22%20xmlns%3Axsi%3D%22http%3A%2F%2F
      www.w3.org%2F2001%2FXMLSchema-instance%22
      %20xsi%3AschemaLocation%3D%22http%3A%2F%2Fwww.w3.org%2F2001
      %2F10%2Fsynthesis%20http%3A%2F%2Fwww.w3.org%2FTR%2Fspeech-synthesis
      %2Fsynthesis.xsd%22%20xml%3Alang%3D%22en-US%22%3E
      That%20is%20a%20%3Cemphasis%3E%20big%20%3C%2Femphasis%3E%20car!
      %3C%2Fspeak%3E"

Response

SSML used:

<?xml version="1.0"?>
<speak version="1.0" xmlns="https://www.w3.org/2001/10/synthesis"
         xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="https://www.w3.org/2001/10/synthesis
                   https://www.w3.org/TR/speech-synthesis/synthesis.xsd"
         xml:lang="en-US">
  That is a <emphasis> big </emphasis> car!
</speak>
Audio synthesized as, “That is a BIG car!”.

SSML tags are used to customize the way a text-to-speech engine creates audio. The tags can be used to add pauses, change emphasis, and change pronunciation. This option is disabled by default but can be requested by emailing sales@ispeech.org. The parameter “action” must set to “ssml” and the parameter “ssml” must be set to a complete SSML XML statement.

The parameter “text” is not used and the parameters voice and speed should be represented using the “voice” and “prosody” SSML tags instead of request parameters.

More information on SSML can be found at: https://www.w3.org/TR/speech-synthesis/.

Math Markup Language (MathML)

curl "https://api.ispeech.org/api/rest?action=convert
      &library=libmath
      &text=%3Cfmath%3E%3Cmrow%3E%3Cmtext%3E%3Csup%3E%2B%3C%2Fsup%3E%3C%2Fmtext%3E
      %3Cmn%3E7%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Ffmath%3E"

Response

MathML used: <mrow><mtext><sup>+</sup></mtext><mn>7</mn></mrow>

Audio synthesized as, “positive 7” instead of plus 7.

MathML tags are used to display and represent mathematical statements. This option is disabled by default but can be requested by emailing sales@ispeech.org.

Remember to set “library” to “libmath” so that the MathML processor loads your text as MathML.

More information on MathML can be found at: https://developer.mozilla.org/en-US/docs/MathML

The following table lists MathML tags supported by the iSpeech API.

MathML Tag Purpose
mfrac Used to display fractions
mi Rendered as an identifier such as function names, variables or symbolic constants.
mn A numeric literal which is normally a sequence of digits with a possible separator (a dot or a comma). However, it is also allowed to have arbitrary text in it which is actually a numeric quantity, for example “eleven”.
mo An operator in a broad sense. Besides operators in strict mathematical meaning, this element also includes “operators” like parentheses, separators like comma and semicolon, or “absolute value” bars.
mroot Displays roots with an explicit index. Two arguments are accepted, which leads to the syntax: <mroot> base index </mroot> .
mrow Groups sub-expressions, which usually contain one or more operators with their respective operands (such as <mi> and <mn> ). This element renders as a horizontal row containing its arguments.
msqrt Displays square roots (no index is displayed). The square root accepts only one argument, which leads to the following syntax: <msqrt> base </msqrt> .
msup, sup Attaches a superscript to an expression.
mtext Renders arbitrary text with no notational meaning, such as comments or annotations.
mspan, span Used for highlighting text or just general styling of an equation
mtable, table Creates tables or matrices. Inside a <mtable> , only <mtr> and <mtd> elements may appear. These elements are similar to <table> , <tr> and <td> elements of HTML.

Example Transactions

HTTP POST URL encoded request for Text to Speech

curl -X POST -d "action=convert&text=hello+world" "https://api.ispeech.org/api/rest"

HTTP POST JSON request for Text to Speech

curl -X POST -H "Content-Type:application/json"
    -d '{"action":"convert","text":"hello world","voice":"usenglishfemale"}'
    "https://api.ispeech.org/api/json"

HTTP POST XML request for Text to Speech

curl -X POST -H "Content-Type:application/xml"
-d "<data>
    <apikey>developerdemokeydeveloperdemokey</apikey>
    <action>convert</action>
    <text>hello world</text>
    <voice>usenglishfemale</voice>
    </data>" "https://api.ispeech.org/api/xml"

HTTP Response

[mp3 audio binary data]

Example of a text-to-speech network transaction with an error. Responses with an error message return HTTP status response code “HTTP/1.0 202 Accepted”.

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &output=rest
      &voice=usenglishfemal"

Response

result=error&code=8&message=Invalid+voice

The following examples are packet captures from TCP connections that used the HTTP protocol. You can compare your network traffic to these transactions to debug code. Wireshark can be used to analyze network connections. A REST client can be used to make these HTTP requests.

Example network transactions containing MathML

HTTP GET, URL Encoded Request and Reply, +7 (says positive 7)

curl "https://api.ispeech.org/api/rest?action=convert
      &voice=usenglishfemale
      &library=libmath
      &format=mp3
      &text=%3Cfmath%3E%3Cmrow%3E%3Cmtext%3E%3Csup%3E%2B%3C%2Fsup%3E%3C%2Fmtext%3E
      %3Cmn%3E7%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Ffmath%3E"

HTTP POST JSON Text-to-Speech request containing MathML

curl -X POST -H "Content-Type:application/json"
  -d '{"action":"convert",
  "text":"<mrow><mtext><sup>-</sup></mtext><span mtagname=\"mfrac\">
  <span class=\"fm-vert fm-frac\">
  <table><tbody>
  <tr><td class=\"fm-num-frac fm-inline\"><mn>3</mn></td></tr>
  <tr><td class=\"fm-den-frac fm-inline\"><mn>5</mn></td></tr>
  </tbody></table>
  </span></span></mrow>",
  "voice":"usenglishfemale",
  "library":"libmath"}' "https://api.ispeech.org/api/json"

HTTP POST XML Text-to-Speech request containing MathML (The text: “+7” gets spoken as “positive seven”)

curl -X POST -H "Content-Type:application/xml"
  -d "<data>
  <action>convert</action>
  <text>&lt;msup&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;span class=&quot;fm-script fm-inline&quot;&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/span&gt;&lt;/msup&gt;</text>
  <library>libmath</library>
  <voice>usenglishfemale</voice>
  </data>" "https://api.ispeech.org/api/xml"

> Response

```shell
[...mp3 binary data...]

The following examples are packet captures from TCP connections that used the HTTP protocol. You can compare your network traffic to these transactions to debug code. Wireshark can be used to analyze network connections. A REST client can be used to make these HTTP requests.

More information on MathML is available on https://www.w3.org/TR/MathML2/ and https://developer.mozilla.org/en-US/docs/MathML

HTTP GET URL encoded Text-to-Speech request containing MathML

URL encoded Request Information
Text: “+7” (says, positive seven)
MathML used: <mrow><mtext><sup>+</sup></mtext><mn>7</mn></mrow>
POST JSON Request Information
Text: “-3/5” (says, negative three fifths)
MathML used: <mrow><mtext><sup>-</sup></mtext><span mtagname="mfrac"><span class="fm-vert fm-frac"><table><tbody><tr><td class="fm-num-frac fm-inline"><mn>3</mn></td></tr><tr><td class="fm-den-frac fm-inline"><mn>5</mn></td></tr></tbody></table></span></span></mrow>
POST XML Request Information
Text: “10^3” (says, 10 to the power of 3)
Math ML: <msup><mn>10</mn><span class="fm-script fm-inline"><mn>3</mn></span></msup>

Errors

Code Summary
1 Invalid API key
2 Could not convert text
3 Not enough credits
4 No action specified
5 Invalid text
6 Too many words
7 Invalid text entry
8 Invalid voice
12 Invalid file format
13 Invalid speed
14 Invalid dictionary
15 Invalid bitrate
16 Invalid frequency
30 Option not enabled for your account. Please contact iSpeech sales at +1 (917) 338-7723 or at sales@ispeech.org to modify your license.
32 Invalid pitch
100 This evaluation account has exceeded its trial period. Please contact iSpeech sales at +1 (917) 338-7723 or at sales@ispeech.org to upgrade your license.
101 Your key has been disabled. Please contact iSpeech sales at +1 (917) 338-7723 or at sales@ispeech.org to modify your license.
997 No api access
998 Unsupported output type
999 Invalid request
1000 Invalid Request Method POST Required
3000 SSML error

Automated Speech Recognition

Request Parameters

Parameter Data Type Example Value
Locale String en-US
Action String recognize
Content-Type String audio/x-wav, audio/amr, audio/speex
Audio String (base64, remove \r\n) UklGRgAKAQBsl/j2+sa0dR […]
Output (optional) String xml, json, rest (default: rest)
Freeform (optional) Integer (0 to 7) 3
Model (optional) String assistant
Speexmode (optional) Integer (1 to 3) 1 (speex codec only)

Locales

Standard Locales

Name Alias Support
English (United States) locale=en-US (default) freeform & command list
English (Canada) locale=en-CA freeform & command list
English (United Kingdom) locale=en-GB freeform & command list
English (Australia) locale=en-AU freeform & command list
Spanish (Spain) locale=es-ES freeform & command list
Spanish (Mexico) locale=es-MX freeform & command list
Italian (Italy) locale=it-IT freeform & command list
French (France) locale=fr-FR freeform & command list
French (Canada) locale=fr-CA freeform & command list
Polish (Poland) locale=pl-PL freeform & command list
Portuguese (Portugal) locale=pt-PT freeform & command list
Catalan (Catalan) locale=ca-ES command list
Chinese (Taiwan) locale=zh-TW command list
Danish (Denmark) locale=da-DK command list
German (Germany) locale=fr-FR command list
Finnish (Finland) locale=it-IT command list
Japanese (Japan) locale=ja-JP command list
Korean (Korea) locale=ko-KR command list
Dutch (Netherlands) locale=nl-NL command list
Norwegian (Norway) locale=nb-NO command list
Portuguese (Brazil) locale=pt-BR command list
Russian (Russia) locale=ru-RU command list
Swedish (Sweden) locale=sv-SE command list
Chinese (People’s Republic of China) locale=zh-CN command list
Chinese (Hong Kong S.A.R.) locale=zh-HK command list

Custom Locales

Contact sales@ispeech.org for details.

Speech Recognition Models

Statistical speech recognition models are used to increase the probability of a correct result. Models with fewer word choices are faster and more accurate than the freeform models. For example, in the food model the words, “7 up” would be recognized as, “7up”. Another example is with a food model would recognize the audio from “ice cream” as “ice cream” instead of “i scream”.

Standard Freeform Models

Name Value Use Case
SMS / General Messages freeform=1 Text Messages
Voice mail freeform=2 Voice Mail
Dictation freeform=3 Normal speech
Message (coming soon) freeform=4 Email
Instant Message (coming soon) freeform=5 Instant Message
Transcript (coming soon) freeform=6
Memo (coming soon) freeform=7 Memorandum
Web (coming soon) freeform=8 Web search

Standard Non-Freeform Models

Name Value Use Case
Assistant model=assistant Personal Assistant
Date model=date Date
NFL model=nfl Football teams
NBA model=nba Basketball teams
US Money model=usmoney US Money
Numbers to 9 model=numbersto9 Numbers, 0 to 9
Numbers to 99 model=numbersto99 Numbers, 0 to 99
Numbers to 999 model=numbersto999 Numbers, 0 to 999
Time model=time Time
Phone number model=phonenumber Phone number
Streets model=streets Streets
Sports Team model=sportsteam Sports Teams
City/State model=citystate US City/States

Custom Models

Contact sales@ispeech.org for details.

Speex Modes

Name Value
Narrowband (8khz) speexmode=1
Wideband (16khz) - Recommended speexmode=2
Ultra Wideband (32kz) speexmode=3

The speexmode variable tells the server which format your Speex data is encoded in for improved speech recognition quality. It is highly recommended you include this parameter when using Speex encoding.

Example Transactions for Freeform Speech

Format of Examples

HTTP REST Request for Speech Recognition

curl -X POST -d "action=recognize&freeform=1&content-type=audio/x-wav&output=rest&locale=en-us&audio=[base64 encoded something.wav without \r\ncharacters]" "https://api.ispeech.org/api/rest"

HTTP JSON Request for Speech Recognition

curl -X POST -H "Content-Type:application/json"
  -d '{"apikey":"developerdemokeydeveloperdemokey","action":"recognize",
  "freeform":"1", "locale":"en-us", "content-type":"audio/x-wav", "output":"rest", "audio":"[base64 encoded something.wav without \r\n characters]”}' "https://api.ispeech.org/api/json"

Response

text=something&confidence=0.0134419081732631&result=success

HTTP XML network request for Speech Recognition

curl -X POST -H "Content-Type:application/xml"
  -d "<data>
      <apikey>developerdemokeydeveloperdemokey</apikey>
      <action>recognize</action>
      <freeform>1</freeform>
      <locale>en-us</locale>
      <content-type>audio/x-wav</content-type>
      <output>xml</output>
      <audio>[base64 encoded something.wav without \r\n characters]</audio>
      </data>" "https://api.ispeech.org/api/xml"

XML Response

<?xml version="1.0" encoding="UTF-8"?>
<data>
<text>something</text>
<confidence>0.0216270890086889</confidence>
<result>success</result>
</data>

The following examples are packet captures from TCP connections that used the HTTP protocol. You can compare your network traffic to these transactions to debug code. Wireshark can be used to analyze network connections.

Command Lists

Command lists are used to limit the possible values returned during speech recognition. For example, if the command list contains only “yes” and “no”, the result will be either “yes” or “no”.

Example Transactions for Command Lists

Formatting of Examples

HTTP XML network request to detect commands from a list

curl -X POST -H "Content-Type:application/xml"
-d "<data>
    <apikey>developerdemokeydeveloperdemokey</apikey>
    <action>recognize</action>
    <locale>en-US</locale>
    <output>xml</output>
    <alias>command1|YESNOMAYBE</alias>
    <YESNOMAYBE>yes|no|maybe</YESNOMAYBE>
    <command1>say %YESNOMAYBE%</command1>
    <content-type>audio/x-wav</content-type>
    <audio>[base64 encoded say_yes.wav without \r\n characters]</audio>
    </data>" "https://api.ispeech.org/api/xml"

XML Response

<?xml version="1.0" encoding="UTF-8"?>
<data>
<text>say yes</text>
<confidence>0.726751327514648</confidence>
<result>success</result>
</data>

HTTP REST network request to detect commands from a list

curl -X POST -d "action=recognize&locale=en-us&content-type=audio%2Fwav&output=rest&alias=command1|NAMES
&NAMES=john|mary|anna&command1=call%20%25NAMES%25&audio=[base64 encoded wav without \r\ncharacters]" "https://api.ispeech.org/api/rest"

HTTP Response

text=call+mary&confidence=0.672464966773987&result=success

HTTP POST JSON request to detect commands from a list

curl -X POST -H "Content-Type:application/json"
-d '{"action":"recognize","locale":"en-US","alias":"command1|YESNOMAYBE","YESNOMAYBE":"yes|no|maybe","command1":"say %YESNOMAYBE%","content-type":"audio/x-wav","output":"rest","audio":"[base64 encoded say_yes.wav without \r\n characters]"}' "https://api.ispeech.org/api/json"

Response

text=say+yes&confidence=0.726751327514648&result=success

Advanced Example, HTTP POST XML request to detect multiple audio commands from multiple lists

curl -X POST -H "Content-Type:application/xml"
  -d "<data>
      <apikey>developerdemokeydeveloperdemokey</apikey>
      <action>recognize</action>
      <locale>en-us</locale>
      <content-type>audio/x-wav</content-type>
      <output>xml</output>
      <alias>command1|command2|MONITORACTIONS|COLORLIST|
      DYNAMITEACTIONS|OBJECTLIST</alias>
      <MONITORACTIONS>on|off|reset</MONITORACTIONS>
      <COLORLIST>blue|green|red|yellow|purple|orange|black|white|cyan</COLORLIST>
      <DYNAMITEACTIONS>explode|fizzle out</DYNAMITEACTIONS>
      <OBJECTLIST>monitor %MONITORACTIONS%|color %COLORLIST%|dynamite  %DYNAMITEACTIONS%</OBJECTLIST>
      <command1>set %OBJECTLIST%</command1>
      <command2>quit menu</command2>
      <audio>[base64 encoded set_dynamite_explode.wav
      without \r\n characters]</audio>
      </data>" "https://api.ispeech.org/api/xml"

XML Response

<?xml version="1.0" encoding="UTF-8"?><data><text>set dynamite explode</text><confidence>0.589247465133667</confidence>
<result>success</result></data>

The following examples are packet captures of TCP connections that use the HTTP protocol. You can compare your network traffic with these transactions to debug code. Wireshark can be used to analyze network connections. A REST client can be used to make these HTTP requests.

Errors

Code Summary
1 Invalid API key
3 Not enough credits
4 No action specified
12 Invalid file format
14 Invalid dictionary
17 Invalid alias list
18 Alias missing
19 Invalid content type
20 Alias list too complex
21 Could not recognize
23 Invalid locale
24 Bad audio data
25 Model not supported or disabled
26 Selected model does not support desired locale
28 Locale not supported
30 Option not enabled for your account. Please contact iSpeech sales at +1 (917) 338-7723 or at sales@ispeech.org to modify your license.
100 This evaluation account has exceeded its trial period. Please contact iSpeech sales at +1 (917) 338-7723 or at sales@ispeech.org to upgrade your license.
101 Your key has been disabled. Please contact iSpeech sales at +1 (917) 338-7723 or at sales@ispeech.org to modify your license.
997 No api access
998 Unsupported output type
999 Invalid request
1000 Invalid Request Method POST Required

Position Markers

Request Parameters

Example HTTP GET Request (Using most variables)

curl "https://api.ispeech.org/api/rest?action=convert
      &text=something
      &voice=usenglishfemale
      &format=mp3
      &frequency=44100
      &bitrate=128
      &speed=1
      &startpadding=1
      &endpadding=1
      &pitch=110
      &filename=myaudiofile"
Parameter Data Type Example Value
Action String markers
Text String Hello World
Voice (optional) String usenglishfemale (default)
Format (optional) String mp3 (default)
Speed (optional) Integer -10 to 10 (default: 0)
Startpadding (optional) Integer (seconds) 5 (default: 0)
Endpadding (optional) Integer (seconds) 5 (default: 0)

Introduction

Position markers provide information regarding word boundaries to allow applications to visually display the current location in spoken audio. It is similar to how a karaoke system would display lyrics.

This is accomplished by first retrieving audio from the iSpeech API (see section 2 for more details), then making a second request for an XML document which contains word boundary information.

Example Transactions for Position Markers

HTTP GET network transaction to retrieve position markers

curl "https://api.ispeech.org/api/rest?action=markers&text=hello+world"

Response

<?xml version="1.0" encoding="UTF-8"?>
<markers>
    <text>hello world</text>
    <voice>usenglishfemale</voice>
    <length>894</length>
    <words>2</words>
    <word>
        <start>70</start>
        <end>339</end>
        <index>1</index>
        <length>270</length>
        <text>hello</text>
    </word>
    <word>
        <start>340</start>
        <end>894</end>
        <index>2</index>
        <length>555</length>
        <text>world</text>
    </word>
</markers>

Note: Marker data is currently only presented in XML form.

To obtain marker information from the iSpeech API, you query the server in the same manner as a normal text-to-speech request. The only difference between a TTS request and a marker request is the “action” parameter, which is set to “convert” for audio, and “markers” for marker information.

Marker Information Usage Technique

Once you have obtained an audio file and the respective marker information XML document, you are ready to highlight text.

There are many methods to processing iSpeech marker information; the following outlines the most basic of those methods. Use the following steps as a baseline implementation.

Media Player Considerations

Your media player must support “location”, “position”, or must notify you of its current progress periodically. For example, in Flash, we set a timer to poll for the audio position every 250 milliseconds. Highlighting will be more accurate with a low interval.

Implementation

If your media player supports retrieval of “current position” or similar, you can follow these basic steps:

  1. Retrieve audio
  2. Retrieve marker information xml
  3. Parse xml into enumerable container/object
  4. Load audio into media player and start playing
  5. Create a timer and set it’s interval to 250 milliseconds
  6. Inside of the newly created timer, at every interval query the media player’s current position
  7. Convert the position to milliseconds (if you have number such as 1.343, simply multiply by 1000)
  8. Move to first (or next) “word” node inside of marker information xml document
  9. Check to see if current position is greater than or equal to the value of ”start” AND ALSO current position is less than or equal to the value of “end”, highlight the specified “text”
  10. If current position is greater than “word” “end” value go to step 8

You can follow the above steps until the audio file is exhausted.

Notes

The same parameters must be sent in the markers request as the original TTS audio request. For example, if you pass a “speed” parameter during audio conversion, you must also send this parameter in your marker information request. If you fail to do so, the marker information will not line up correctly.

File type affects audio length. A MP3 file is always longer than a WAV file due to compression padding. The API will modify the file length accordingly.

Errors

Code Summary
1 Invalid API key
2 Could not convert text
3 Not enough credits
4 No action specified
5 Invalid text
6 Too many words
7 Invalid text entry
8 Invalid voice
12 Invalid file format
13 Invalid speed
14 Invalid dictionary
15 Invalid bitrate
16 Invalid frequency
30 Option not enabled for your account. Please contact iSpeech sales at +1 (917) 338-7723 or at sales@ispeech.org to modify your license.
33 Invalid text or markers not supported for the selected voice
34 Markers do not support audio padding or other option.
100 This evaluation account has exceeded its trial period. Please contact iSpeech sales at +1 (917) 338-7723 or at sales@ispeech.org to upgrade your license.
101 Your key has been disabled. Please contact iSpeech sales at +1 (917) 338-7723 or at sales@ispeech.org to modify your license.
997 No api access
998 Unsupported output type
999 Invalid request
1000 Invalid Request Method POST Required

Visemes

Request Parameters

Parameter Data Type Example Value
Action String viseme
Text String Hello World
Voice (optional) String usenglishfemale (default)
Format (optional) String mp3 (default)
Speed (optional) Integer -10 to 10 (default: 0)
Startpadding (optional) Integer (seconds) 5 (default: 0)
Endpadding (optional) Integer (seconds) 5 (default: 0)

Introduction

Visemes provide information regarding the mouth position and time interval of spoken audio which allows applications to visually pronounce audio.

This is accomplished by first retrieving audio from the iSpeech API (see section 2 for more details), then making a second request for an XML document which contains viseme information.

Example Transaction for Viseme Retrieval

HTTP GET network transaction to retrieve viseme positions

curl "https://api.ispeech.org/api/rest?action=viseme&text=hello+world"

Response

<visemes>
   <text>hello world</text>
   <voice>usenglishfemale</voice>
   <length>753</length>
   <frames>9</frames>
   <viseme>
      <start>1</start>
      <end>74</end>
      <index>1</index>
      <length>74</length>
      <mouth>12</mouth>
   </viseme>
   <viseme>
      <start>75</start>
      <end>102</end>
      <index>2</index>
      <length>28</length>
      <mouth>4</mouth>
   </viseme>
   <viseme>
      <start>103</start>
      <end>182</end>
      <index>3</index>
      <length>80</length>
      <mouth>14</mouth>
   </viseme>
   <viseme>
      <start>183</start>
      <end>269</end>
      <index>4</index>
      <length>87</length>
      <mouth>8</mouth>
   </viseme>
   <viseme>
      <start>270</start>
      <end>359</end>
      <index>5</index>
      <length>90</length>
      <mouth>7</mouth>
   </viseme>
   <viseme>
      <start>360</start>
      <end>470</end>
      <index>6</index>
      <length>111</length>
      <mouth>5</mouth>
   </viseme>
   <viseme>
      <start>471</start>
      <end>660</end>
      <index>7</index>
      <length>190</length>
      <mouth>14</mouth>
   </viseme>
   <viseme>
      <start>661</start>
      <end>752</end>
      <index>8</index>
      <length>92</length>
      <mouth>19</mouth>
   </viseme>
   <viseme>
      <start>753</start>
      <end>753</end>
      <index>9</index>
      <length>1</length>
      <mouth>0</mouth>
   </viseme>
</visemes>

To obtain viseme information from the iSpeech API, you query the server in the same manner as a normal text-to-speech request. The only difference between a TTS request and a marker request is the “action” parameter, which is set to “convert” for audio, and “viseme” for viseme information.

Viseme Chart

Mouth 0

 Mouth 1

Mouth 2

Mouth 3

Mouth 4

Mouth 5

Mouth 6

 Mouth 7

Mouth 8

Mouth 9

Mouth 10

Mouth 11

 Mouth 12

Mouth 13

Mouth 14

Mouth 15

Mouth 16

 Mouth 17

Mouth18

 Mouth 19

Mouth 20

Mouth 21

Viseme Usage Technique

Once you have obtained an audio file and the respective viseme information XML document, you are ready to animate mouth positions to simulate speaking.

There are many methods to processing iSpeech viseme information; the following outlines the most basic of those methods. Use the following steps as a baseline implementation.

Media Player Considerations

Your media player must support “location”, “position”, or must notify you of its current progress periodically. For example, in Flash, we set a timer to poll for the audio position every 250 milliseconds. Mouth positioning will be more accurate with a low interval.

Implementation

If your media player supports retrieval of “current position” or similar, you can follow these basic steps:

  1. Retrieve audio
  2. Retrieve viseme information xml
  3. Parse xml into enumerable container/object
  4. Load audio into media player and start playing
  5. Create a timer and set it’s interval to 250 milliseconds
  6. Inside of the newly created timer, at every interval query the media player’s current position
  7. Convert the position to milliseconds (if you have number such as 1.343, simply multiply by 1000)
  8. Move to first (or next) “word” node inside of marker information xml document
  9. Check to see if current position is greater than or equal to the value of ”start” AND ALSO current position is less than or equal to the value of “end”, highlight the specified “text”
  10. If current position is greater than “word” “end” value go to step 8

You can follow the above steps until the audio file is exhausted.

Notes

The same parameters must be sent in the viseme request as the original TTS audio request. For example, if you pass a “speed” parameter during audio conversion, you must also send this parameter in your marker information request. If you fail to do so, the viseme will not line up correctly.

File type affects audio length. A MP3 file is always longer than a WAV file due to compression padding. The API will modify the file length accordingly.

Errors

Code Summary
1 Invalid API key
2 Could not convert text
3 Not enough credits
4 No action specified
5 Invalid text
6 Too many words
7 Invalid text entry
8 Invalid voice
12 Invalid file format
13 Invalid speed
14 Invalid dictionary
15 Invalid bitrate
16 Invalid frequency
29 Viseme not supported for the selected voice.
30 Option not enabled for your account. Please contact iSpeech sales at +1 (917) 338-7723 or at sales@ispeech.org to modify your license.
32 Invalid pitch
100 This evaluation account has exceeded its trial period. Please contact iSpeech sales at +1 (917) 338-7723 or at sales@ispeech.org to upgrade your license.
101 Your key has been disabled. Please contact iSpeech sales at +1 (917) 338-7723 or at sales@ispeech.org to modify your license.
997 No api access
998 Unsupported output type
999 Invalid request
1000 Invalid Request Method POST Required

Disclaimer

iSpeech Inc. (“iSpeech”) has made efforts to ensure the accuracy and completeness of the information in this document. However, iSpeech Inc. disclaims all representations, warranties and conditions, whether express or implied, arising by statute, operation of law, usage of trade, course of dealing or otherwise, with respect to the information contained herein. iSpeech Inc. assumes no liability to any party for any loss or damage, whether direct, indirect, incidental, consequential, special or exemplary, with respect to (a) the information; and/or (b) the evaluation, application or use of any product or service described herein.

iSpeech Inc. disclaims any and all representation that its products or services infringe upon any existing or future intellectual property rights. iSpeech Inc. owns and retains all right, title and interest in and to the iSpeech Inc. intellectual property, including without limitation, its patents, marks, copyrights and technology associated with the iSpeech Inc. services. No title or ownership of any of the foregoing is granted or otherwise transferred hereunder. iSpeech Inc. reserves the right to make changes to any information herein without further notice.

Revision History

Publish Date Updates
Aug 8, 2011 Document created
Sept 13, 2011 Added ASR
Sept 21, 2011 Added AMR to ASR
Nov 9, 2011 Added voice command examples
Nov 10, 2011 Removed references to ASR Raw POST
Nov 11, 2011 Made output variable explicit for ASR and voice list examples
Nov 17, 2011 Specified HTTP POST/GET instead of REST, fixed /r/n typos
Nov 22, 2011 Added reference for Speex in ASR content-type example
Dec 12, 2011 Added endpadding and startpadding variables
Dec 12, 2011 Added TTS examples, added background highlighting to emphasize examples
Aug 24, 2012 Added position markers and visemes
Aug 24, 2012 Added Flash, Javascript/Flash, Ruby, Python, Perl SDKs
Aug 24, 2012 Added link to automated payment system
Aug 24, 2012 Added pitch parameter to TTS
Aug 30, 2012 Added standard non-freeform speech recognition models
Aug 30, 2012 Added speech recognition speex modes
Sept 10, 2012 Added bit depth
Sept 10, 2012 Added TTS file formats: alaw, ulaw, vox, and mp4
Sept 10, 2012 Added errors
Sept 10, 2012 Changed ASR language to locale
Oct 3, 2012 Add filename parameter to TTS
Nov 12, 2012 Removed eurdutchmale voice
Jan 22, 2013 Added Math Markup Language (MathML) information and examples
Jan 24, 2013 Added Speech Synthesis Markup Language (SSML) information and examples
Mar 4, 2013 Corrected content-length for JSON TTS example
Mar 13, 2013 Updated ASR locale list, added Web ASR freeform mode.
Sept 7, 2016 Updated supported language list.