Issue while converting audio file from .wav to MP3 using LAME

Question

I am trying to convert Linear PCM audio file (.wav) to MP3 using LAME for my iOS app. I am successfully able to do it except for one issue , the created MP3 file turns out to be smaller than the orignal .wav file. For 30 seconds wav file , created MP3 file was of 27 seconds and audio of last 3 seconds was chopped off. For 5 mins audio about 30 seconds of audio was chopped off in resulting MP3.

I am not really sure what is causing the issue , i have tried changing around few things but nothing worked. Can somebody help me out and push me towards the right direction?

Here is the code I am using for this.

    int read, write;
    FILE *pcm = fopen([mergeFile cStringUsingEncoding:1], "rb");  //source
    fseek(pcm, 4*1024, SEEK_CUR);                                   //skip file header
    FILE *mp3 = fopen([mp3FilePath cStringUsingEncoding:1], "wb");  //output

    const int PCM_SIZE = 8192;
    const int MP3_SIZE = 8192;
    short int pcm_buffer[PCM_SIZE*2];
    unsigned char mp3_buffer[MP3_SIZE];

    lame_t lame = lame_init();
    lame_set_in_samplerate(lame, 44100);
    lame_set_VBR(lame, vbr_default);
    lame_init_params(lame);

    do {
        read = fread(pcm_buffer, 2*sizeof(short int), PCM_SIZE, pcm);
        NSLog(@"");
        if (read == 0)
            write = lame_encode_flush(lame, mp3_buffer, MP3_SIZE);
        else
            write = lame_encode_buffer_interleaved(lame, pcm_buffer, read, mp3_buffer, MP3_SIZE);



    } while (read != 0);




    lame_close(lame);
    fclose(mp3);
    fclose(pcm);

Answer 1

I did same task and It's working fine for me.. The only differance I am seeing in above code is You have to replace lame_set_VBR(lame, vbr_default); this statement with lame_set_VBR(lame, vbr_off);

This should work fine. Please check with this change.