I'm creating an ios app using your amazing fingerprint api.

I have just a question: i have create in my app a section with mp3 files.

I have seen that if i play an mp3 and then i stop it, if i try to make a search using your fingerprint function it gives this problem: GNFPX Fingerprint Creation (OSStatus) -50

So i think the problem is if i play a music mp3, also if i stop it, the fingerprint doesn't start like if microphone will be closed.

So how can i do to solve this problem? I would like to create an app with a section with mp3 and a section with your recognizing fingerprint function.
Is there the possibility to ask to open mic everytime i click on mic search using your api key?

Let me know.

Thank you.


Hi Alberto,Thanks for the question. Can you please clarify which SDK you are using (GNSDK or Mobile Client?) and which fingerprinting function you are getting the error from? In general our fingerprinting requires a specific duration of audio to be recorded (between 3 and 15 seconds, depending on which function and mode), it is possible that by pausing the song you are not feeding in enough audio for the SDK to generate a fingerprint. Also, you may wish to post this question on Stack Overflow (, and tag it with "Gracenote".