Set bitrate of ogg file generated by libsndfile libraries

Question

I used the code below to convert sound files to ogg vorbis, but i don't found on the documentation of libsndfile how to set the bitrate of the output file, which is always set to 128 kb/s. Is possible to change the bitrate of the output file generated by libsndfile?

#include <sndfile.hh>

#define BUFFER_LEN 4096

void convert(char *infilename, char *outfilename)
{
    static double data[BUFFER_LEN];
    SNDFILE *infile, *outfile;
    SF_INFO sfinfo;
    int readcount;

    infile = sf_open(infilename, SFM_READ, &sfinfo);
    sfinfo.format = SF_FORMAT_OGG | SF_FORMAT_VORBIS;
    outfile = sf_open(outfilename, SFM_WRITE, &sfinfo);

    while ((readcount = sf_read_double(infile, data, BUFFER_LEN)))
    {
        sf_write_double(outfile, data, readcount);
    }

    sf_close(infile);
    sf_close(outfile);
}

Answer 1

With libsndfile there is no way to set a specific bitrate. Setting a specific constant bit rate it usually a bad idea anyway as the constant bitrate is likely to be too low for some parts of the sonf and too high for other parts.

With libsndfile you can however set various compression levels which always use variable bitrate. See : http://www.mega-nerd.com/libsndfile/command.html#SFC_SET_VBR_ENCODING_QUALITY