Android TTS text longer than 4k chars not playing

Question

I am using TextToSpeech to play some long texts sometimes, and I have noticed that since Android 4.1.2 if the text is longer than 4000 chars, it does not play.

I do not get any errors, but the text won't be played. Until now I was able to reproduce this just on Android 4.1.2(Samsung Galaxy Nexus, Nexus7).

Is this a bug just in 4.1.2 or is this normal (although I did not find any documentation regarding this behaviour)?

Also I have found a post : onUtteranceCompleted() lost if TTS received is too long which indicates different problems with texts longer than 4000 chars.

EDIT: I tried to split my string in 4k length chunks, and send it to TTS using QUEUE_ADD and I came across another bug: QUEUE_ADD does not work, instead it flushes the existing queue, and only the last chunk gets played.

EDIT2 : this is my call to TTS

mTTS.speak(longText, TextToSpeech.QUEUE_FLUSH, null);

Answer 1

MAX_SPEECH_ITEM_CHAR_LENGTH = 4000 in TtsService.java, on 4.1 I see a warn in the code:

    @Override
    public boolean isValid() {
        if (mText == null) {
            Log.wtf(TAG, "Got null text");
            return false;
        }
        if (mText.length() >= MAX_SPEECH_ITEM_CHAR_LENGTH) {
            Log.w(TAG, "Text too long: " + mText.length() + " chars");
            return false;
        }
        return true;
    }

looks like 2.3 splits the text instead, so teorically your code should work on android < 4.1 and not on newer (I don't known when the split was removed), instead you have the opposite :) that is a bit strange