Is there any LAME C++ wrapper\simplifier (working on Linux Mac and Win from pure code)?

Lame really isn't difficult to use, although there are a lot of optional configuration functions if you need them. It takes slightly more than 4-5 lines to encode a file, but not much more. Here is a working example I knocked together (just the basic functionality, no error checking):

#include <stdio.h>
#include <lame/lame.h>

int main(void)
{
    int read, write;

    FILE *pcm = fopen("file.pcm", "rb");
    FILE *mp3 = fopen("file.mp3", "wb");

    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);
        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);
        fwrite(mp3_buffer, write, 1, mp3);
    } while (read != 0);

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

    return 0;
}

inspired by Mike Seymour's answer I created a pure C++ wrapper which allows to encode / decode WAV and MP3 files in just 2 lines of code

convimp3::Codec::encode( "test.wav", "test.mp3" );
convimp3::Codec::decode( "test.mp3", "test_decoded.wav" );

no need to bother about sample rate, byte rate and number of channels - this info is obtained from WAV or MP3 file during encoding / decoding.

The library doesn't use old C i/o functions, but C++ streams only. I find it more elegant.

For convinience I created a very thin C++ wrapper over LAME and called it lameplus and a small library for extraction of sampling information from WAV files.

All files can be found here:

encoding/decoding: https://github.com/trodevel/convimp3

lameplus: https://github.com/trodevel/lameplus

wav handling: also on github, repository is wave