Question

For everyone using Android’s voice recognition API, there used to be a handy RecognitionListener you could register that would push various events to your callbacks. In particular, there was the following onBufferReceived(byte[]) method:

public abstract void onBufferReceived (byte[] buffer)

Since: API Level 8 More sound has been received. The purpose of this
function is to allow giving feedback to the user regarding the
captured audio. There is no guarantee that this method will be called.

Parameters buffer a buffer containing a sequence of big-endian 16-bit
integers representing a single channel audio stream. The sample rate
is implementation dependent.

Although the method explicitly states that there is no guarantee it will be called, in ICS and prior it would effectively be called 100% of the time: regularly enough, at least, that by concatenating all the bytes received this way, you could reconstruct the entire audio stream and play it back.

For some reason, however, in the Jellybean SDK, this magically stopped working. There’s no notice of deprecation and the code still compiles, but the onBufferReceived is now never called. Technically this isn’t breaking their API (since it says there’s “no guarantee” the method will be called), but clearly this is a breaking change for a lot of things that depended on this behaviour.

Does anybody know why this functionality was disabled, and if there’s a way to replicate its behaviour on Jellybean?

Clarification: I realize that the whole RecognizerIntent thing is an interface with multiple implementations (including some available on the Play Store), and that they can each choose what to do with RecognitionListener. I am specifically referring to the default Google implementation that the vast majority of Jellybean phones use.

Answer 1

Google does not call this method their Jelly Bean speech app (QuickSearchBox). Its simply not in the code. Unless there is an official comment from a Google Engineer I cannot give a definite answer “why” they did this. I did search the developer forums but did not see any commentary about this decision.

The ics default for speech recognition comes from Google’s VoiceSearch.apk. You can decompile this apk and see and find see there is an Activity to handle an intent of action *android.speech.action.RECOGNIZE_SPEECH*. In this apk I searched for “onBufferReceived” and found a reference to it in com.google.android.voicesearch.GoogleRecognitionService$RecognitionCallback.

With Jelly Bean, Google renamed VoiceSearch.apk to QuickSearch.apk and made a lot of new additions to the app (ex. offline dictation). You would expect to still find an onBufferReceived call, but for some reason it is completely gone.