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Hi,

I was using Echoprint before so I already implemented a recording using the mic of the iphone. So i wanted to replace the Echorpting fingerprint generation and Server lookup with gracenote as i am pretty sure it's more reliable :) 

 

It kind of works but I am wondering why I do always get a fingerprint mentioning a "very_low" quality of the audio when I use [GNOperations fingerprintMIDStreamFromPcmconfigsampleBuffer: ]. 

 

The audio recording does have following settings and stores the recording into a caf file:

[recordSettings setObject:[NSNumber numberWithInt:kAudioFormatLinearPCM] forKey:AVFormatIDKey];

[recordSettings setObject:[NSNumber numberWithFloat:11025.0] forKey: AVSampleRateKey];

[recordSettings setObject:[NSNumber numberWithInt:1] forKey:AVNumberOfChannelsKey];

[recordSettings setObject:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];

 

After recording i use [GNSampleBuffer gNSampleBuffer:[...] numChannels:1 sampleRate:11025.0] to create a sample buffer to use with the GNOperations class. 

 

As I mentioned, this always returns a Fingerprint containing "low quality":

<ALGORITHM>

    <NAME>Philips</NAME>

    <VERSION>1.1</VERSION>

    <QUERY>Philips&quot;1.1</QUERY>

    <BLOCK_LENGTH>3</BLOCK_LENGTH>

    <FORMAT>COMPRESSED</FORMAT>

  </ALGORITHM>

  <AUDIO>

    <QUALITY>VERY_LOW</QUALITY>

  </AUDIO>

<CLASSIFIER VERSION="1.2">

<CLASSIFICATION TYPE="2001" APPLY="True">503</CLASSIFICATION>

<CLASSIFICATION TYPE="1001" APPLY="True">1041</CLASSIFICATION>

</CLASSIFIER>  

...

 

 

As I am not that much into audio programming I do not know how to improve the quality of the audio. 

Do you have any suggestions? I still do not want to use the gracenote implementation of the recording as i want to display meter updates.

 

 

Hope you have some interesting insights :)

 

Thank you very much,

Marco

 

 

 

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