CODEWITHSUNDEEP
pcmaudiokitlame
George L
George L

Reputation: 1738

Crash trying to convert PCM to MP3 using AudioKit

I am trying to convert in real time the audio from my iPhone mic to MP3.

I have it setup as such:

        let format = AVAudioFormat(commonFormat: AVAudioCommonFormat.pcmFormatInt16,
                               sampleRate: 44100.0,
                               channels: 1,
                               interleaved: true)

    mic.avAudioUnitOrNode.installTap(onBus: 0, bufferSize: AVAudioFrameCount((format?.sampleRate)!), format: format, block: { (buffer: AVAudioPCMBuffer!, time: AVAudioTime!) -> Void in

        let audioBuffer : AVAudioBuffer = buffer
        self.audioProcessor?.processBuffer( audioBuffer.mutableAudioBufferList)
    })


-(void)processBuffer: (AudioBufferList*) audioBufferList;
{
    const int PCM_SIZE = 8192;
    const int MP3_SIZE = 8192;
    short int pcm_buffer[PCM_SIZE*2];
    unsigned char mp3_buffer[MP3_SIZE];
    int write = lame_encode_buffer_interleaved(mLame, pcm_buffer,(int*) audioBufferList->mBuffers[0].mData, mp3_buffer, MP3_SIZE);

   //some other stuff
}

but I am getting a crash as soon as I get to the encoding portion.

EDIT:

I got it to stop crashing, but the audio quality is pretty harsh:

    int size = audioBufferList->mBuffers[0].mDataByteSize / 2;
    unsigned char mp3_buffer[size * 4];
    int write = lame_encode_buffer(mLame, audioBufferList->mBuffers[0].mData, audioBufferList->mBuffers[0].mData, size, mp3_buffer, size*4);

Upvotes: 1

Views: 335

Answers (1)

George L
George L

Reputation: 1738

There was a mismatch on the sampling rates between the source audio and the encoder.

Upvotes: 2

Related Questions