Voice Synthesis - Android
VDK features three Voice Synthesis libraries: CSDK (Cerence), Baratinoo (Voxygen) and VtApi (ReadSpeaker).
Configuration
Voice synthesis engines must be configured before the program starts. Here is a complete setup with 2 channels, one for each language possible.
Configuration parameter | Type | Description |
|---|---|---|
| String | The configuration version number. Constant |
| String | The voices data location. This is relative to vsdk.json itself, NOT the program's working dir! |
| Object | Contains collection of channel description. The key is the channel name. |
| Array | List of the voices used by the channel. |
An empty channel list will trigger an error, as well as an empty voice list!
You can use the VDK to generate the configuration and the data directory. After creating a custom project with the channels and the voices of your choice, just export it to your binary location.
Voice format
Each engine has its own voice format, described in the following table:
Engine | Format | Example |
|---|---|---|
vsdk-csdk |
|
|
vsdk-vtapi |
|
|
vsdk-baratinoo |
|
|
Starting the engine
com.vivoka.vsdk.Vsdk.init(mContext, "config/main.json", vsdkSuccess -> {
if (vsdkSuccess)
{
Engine.getInstance().init(mContext, engineSuccess -> {
if (engineSuccess)
{
// at this point the TtsEngine has been correctly initialized
}
});
}
});Creating a channel
Remember, channel must be configured beforehand!
Channel channelFrf = Engine.getInstance().makeChannel("channelFrf", "frf,aurelie,embedded-compact");
The engine instance can't die while at least one channel instance is alive. Destruction order is important!
Speech Synthesis
channelFrf.synthesisFromText("Bonjour ! Je suis une voix synthétique", () -> {
// channelFrf.synthesisResult contains the audioData to play
});
// Also works with SSML input
final String ssml = "<speak version=\"1.0\" xmlns=\"http://www.w3.org/2001/10/synthesis\" xml:lang=\"fr-FR\">Bonjour Vivoka</speak>";
channelFrf.synthesisFromSSML(ssml, () -> {
// channelFrf.synthesisResult contains the audioData to play
});Speech Synthesis is asynchronous! That means the call will not block the thread during the synthesis.
The audio data is a 16bit signed Little-Endian PCM buffer. Channel count is always 1 and sample rate varies depending on the engine:
Engine | Sample Rate (kHz) |
|---|---|
csdk | 22050 |
baratinoo | 24000 |
vtapi | 22050 |
Playing the result
VSDK provides an audio player. Playing the result is very easy:
AudioPlayer.play(channel.synthesisResult.getAudioData(),
channel.synthesisResult.getSampleRate(),
new AudioTrack.OnPlaybackPositionUpdateListener()
{
@Override
public void onMarkerReached(AudioTrack track) {}
@Override
public void onPeriodicNotification(AudioTrack track) { }
});Storing the result on disk
channel.synthesisResult.saveToFile("directory", "filename", new ICreateAudioFileListener(){}); Only PCM extension is available, which means the file has no audio header of any sort.