I have a TTS (text-to-speech) system that produces audio in numpy-array form whose data type is np.float32
. This system is running in the backend and I want to transfer the data from the backend to the frontend to be played when a certain event happens.
The obvious solution for this problem is to write the audio data on disk as a wav file and then pass the path to the frontend to be played. This worked fine, but I don’t want to do that for administrative reasons. I just want to transfer only the audio data (numpy array) to the frontend.
What I have done till now is the following:
backend
text = "Hello"
wav, sr = tts_model.synthesize(text)
data = {"snd", wav.tolist()}
flask_response = app.response_class(response=flask.json.dumps(data),
status=200,
mimetype='application/json' )
# then return flask_response
frontend
// gets wav from backend
let arrayData = new Float32Array(wav);
let blob = new Blob([ arrayData ]);
let url = URL.createObjectURL(blob);
let snd = new Audio(url);
snd.play()
That what I have done till now, but the JavaScript throws the following error:
Uncaught (in promise) DOMException: Failed to load because no supported source was found.
This is the gist of what I’m trying to do. I’m so sorry, you can’t repreduce the error as you don’t have the TTS system, so this is an audio file generated by it which you can use to see what I’m doing wrong.
Other things I tried:
- Change the audio datatype to
np.int8
,np.int16
to be casted in the JavaScript byInt8Array()
andint16Array()
respectively. - tried different types when creating the
blob
such as{"type": "application/text;charset=utf-8;"}
and{"type": "audio/ogg; codecs=opus;"}
.
I have been struggling in this issue for so long, so any help is appriciated !!
Convert wav array of values to bytes
Right after synthesis you can convert numpy array of wav to byte object then encode via base64.
This can be used directly to create html audio tag as source (with flask):
So, all you need is to convert
wav
,sr
toaudio_data
representing raw.wav
file. And use as parameter ofrender_template
for your flask app. (Solution without sending)Or if you send
audio_data
, in.js
file where you accept response, useaudio_data
to construct url (would be placed assrc
attribute like in html):because:
Your sample as is does not work out of the box. (Does not play)
However with:
Flask
js
Original Poster Edit
So, what I ended up doing before (using this solution) that solved my problem is to:
np.float32
tonp.int16
:scipy.io.wavfile
: