Flutter

Update:

Overview

This document will guide developer using the real-time voice translation SDK (RTVT) from LiveData, to implement translation services in real-time voice scenarios.

Integration

Service Activation

To integration the LiveData RTVT SDK, you need to register an personal/enterprise account from LiveData official website (https://www.ilivedata.com/) , create a real-time voice translation service project and update the corresponding project parameters in SDK.

Version Support

  • Flutter 2.10.5 and above.
  • Dart 2.14.0 and above.
  • Prepare the corresponding development and runtime environment according to your target platform:
Platform Development and runtime environment
Android Android 5.0 and above
iOS iOS 10 and above

Requirements

  • Audio format : Only PCM format is supported
  • Sampling rate: 16KHz
  • Encoding: 16-bit depth
  • Channels: Monaural

Configuring build settings

  • Setting Linker Flags
    • Go to the “Build Settings” tab under your project’s “TARGETS”.
    • Add the “-ObjC” flag to the “Other Linker Flags” section.
    • Make sure to do this in the “ALL” configurations view.
    • Ensure that the “O” and “C” in “-ObjC” are capitalized and the preceding hyphen “-” is included.
  • Ensuring Support for Objective-C++
    • Your project needs to have at least one source file with a “.mm” extension to support Objective-C++.
    • If not present, you can rename an existing “.m” file to “.mm”.
  • Adding Libraries
    • Add the “libresolv.9.tbd” library to your project.
    • This is typically done in the “Link Binary With Libraries” section.

Login

void rtvtLogin(String token, String endpoint, int pid, RtvtDelegate delegate,
void Function() success,
void Function(int errorCode, String errorEx) fail)
Parameter Type M/O Description
token string M token generation using key from LiveData Console service configuration
endpoint string M endpoint （check from LiveData Console service configuration）
pid int M project ID
delgate - - imported callback object
success - - login success callback
fail - - login fail callback

Callback object

mixin RtvtDelegate {

  void rtvtRecognizeResult(
      int streamId, String result, int startTs, int endTs, int recTs);

  void rtvtTranslatedResult(
      int streamId, String result, int startTs, int endTs, int recTs);

  void rtvtTmpRecognizeResult(
      int streamId, String result, int startTs, int endTs, int recTs);

  void rtvtReloginResult(int code, String ex);
}
Parameter Description
result callback result
startTs ms timestamp of voice starts
endTs ms timestamp of voice ends
recTs ms timestamp of voice recognition
code the prompt code for the reconnection result, where 0 indicates a successful reconnection.

Start translate

void startTranslate(bool asrResult, bool asrTempResult, bool transResult, String srcLanguage, String destLanguage, List[String] srcAltLanguage, String userId,
void Function(int streamId) success,
void Function(int errorCode, String errorEx) fail)
Parameter Type M/O Description
asrResult bool M Set whether the final result of voice recognition is needed. The default is true.
transResult bool M Set whether the final result of translate is needed. The default is true.
asrTempResult bool M Set whether the temporary result of voice recognition is needed. The default is false.
srcLanguage string M source language
destLanguage string M arget language.
The target language can be passed as an empty string if only transcription is needed.
srcAltLanguage array O The range of alternative languages for the source language supports a maximum of three language types.
userId string M user id, input as needed.
success - - callback when obtain the streamId successful
fail - - callback when obtain the streamId fail

Notice:
1.In scenarios where callback of recognition results is needed, asrResult should be set to true, srcLanguage is mandatory, and srcAltLanguage is optional.
2.In scenarios where callback of translation results is needed, transResult should be set to true, destLanguage is mandatory, and it cannot be an empty string.
3.If temporary recognition results and temporary translation results are needed, tempResult should be set to true.
4.If a language is passed into srcAltLanguage, the RTVT will default to a language recognition process first. The beginning part of the voice (about 3 seconds) will be used for language recognition, and the subsequent recognition/translation results will be returned normally.
5.If the language passed is not within the range of supported languages, a error message indicating “language not supported” will be displayed; if the language passed is not enabled in the project, a message indicating “project does not support” will be displayed.
6.In the event of a automatic reconnection, this method must be called again to obtain a new streamId.

Send voice clip

void sendPcmData(int streamId, Uint8List pcmData, int seq, int ts,
void Function() success,
void Function(int errorCode, String errorEx) fail)
Parameter Type M/O Description
streamId int M stream ID
seq int M audio segment sequence number (preferably in order)
pcmData Uint8List M audio data，default of 640 bytes
ts int M audio frame reference timestamp
success - - success callback
fail - - fail callback

Notice： If no voice data is sent for a certain period of time, the RTVT will perform a timeout process. At this point, it is necessary to call the startTranslate method again to obtain a new streamId.

Stop translate

void stopTranslate(int streamId, int lastSeq,
void Function() success,
void Function(int errorCode, String errorEx) fail)
Parameter Type M/O Description
streamId int M stream Id need to translate
lastSeq int M the final audio frame
success - - success callback
fail - - fail callback

Close RTVT

void close()

Error code

Error code Description
800000 unknown error
800001 unverified link
800002 login failed
800003 expired token
800004 invalid verification time
800005 invalid token
800006 streamId does not exist

More information

For SDK download and more information, please go to Github.