I've created an Android Application and I've connected different watson services, available on Bluemix, to it: Natural Language Classifier, Visual Recognition and Speech to Text.
1) The first and the second work well; I've a little problem with the third one about the format of the audio. The app should register a 30sec audio, save it on memory and send to the service to obtain the corresponding text. I've used an instance of the class MediaRecorder to register the file. It works, but the available Output formats are AAC_ADTS, AMR_WB, AMR_NB, MPEG_4, THREE_GPP, RAW_MR and WEBM.
The service, differently, accepts in input these formats: FLAC, WAV, PCM. What is the best way to convert the audio file from the first set of outputs to the second one? Is there a simple method to do that? For example, from THREE_GPP or MPEG_4 to WAV or PCM.
I've googled searching infos and ideas, but I've found only few and long-time methods, not well understood. I'm looking for a fast method, because I would make the latency of conversion and elaboration by the service as short as possible.
Is there an available library that does this? Or a simple code snippet?
2) One last thing:
SpeechResults transcript = service.recognize(audio, HttpMediaType.AUDIO_WAV);
System.out.println(transcript);
"transcript" is a json response. Is there a method to directly extract only the text, or should I parse the json?
Any suggestion will be appreciated! Thanks!
To convert the audio records in different formats/encodings you could: - find an audio encoder lib to include into your app which supports the required libs but it could very heavy to run on a mobile device (if you find the right lib) - develop an external web application used to send your record, make it encoded and returned as a file or a stream - develop a simple web application working like a live proxy that gets the record file, makes a live conversion of the file and send to Watson
Both the 2nd option and the 3rd one expects to use an encoding tool like ffmpeg. The 3rd one is lighter to develop but a little bit more complex but could allow you to save 2 http request from you android device