'Gives a guess about the encoder settings used. Returns an empty
string if unknown.
The guess is mostly correct in case the file was encoded with
the default options (-V --preset --alt-preset --abr -b etc) and no
other fancy options.
Args:
major (int)
minor (int)
Returns:
text'

def guess_settings(self, major, minor):

    version = (major, minor)
    if (self.vbr_method == 2):
        if ((version in ((3, 90), (3, 91), (3, 92))) and self.encoding_flags):
            if (self.bitrate < 255):
                return (u'--alt-preset    %d' % self.bitrate)
            else:
                return (u'--alt-preset    %d+' % self.bitrate)
        if (self.preset_used != 0):
            return (u'--preset    %d' % self.preset_used)
        elif (self.bitrate < 255):
            return (u'--abr    %d' % self.bitrate)
        else:
            return (u'--abr    %d+' % self.bitrate)
    elif (self.vbr_method == 1):
        if (self.preset_used == 0):
            if (self.bitrate < 255):
                return (u'-b    %d' % self.bitrate)
            else:
                return u'-b    255+'
        elif (self.preset_used == 1003):
            return u'--preset    insane'
        return (u'-b    %d' % self.preset_used)
    elif (version in ((3, 90), (3, 91), (3, 92))):
        preset_key = (self.vbr_quality, self.quality, self.vbr_method, self.lowpass_filter, self.ath_type)
        if (preset_key == (1, 2, 4, 19500, 3)):
            return u'--preset    r3mix'
        if (preset_key == (2, 2, 3, 19000, 4)):
            return u'--alt-preset    standard'
        if (preset_key == (2, 2, 3, 19500, 2)):
            return u'--alt-preset    extreme'
        if (self.vbr_method == 3):
            return (u'-V    %s' % self.vbr_quality)
        elif (self.vbr_method in (4, 5)):
            return (u'-V    %s    --vbr-new' % self.vbr_quality)
    elif (version in ((3, 93), (3, 94), (3, 95), (3, 96), (3, 97))):
        if (self.preset_used == 1001):
            return u'--preset    standard'
        elif (self.preset_used == 1002):
            return u'--preset    extreme'
        elif (self.preset_used == 1004):
            return u'--preset    fast    standard'
        elif (self.preset_used == 1005):
            return u'--preset    fast    extreme'
        elif (self.preset_used == 1006):
            return u'--preset    medium'
        elif (self.preset_used == 1007):
            return u'--preset    fast    medium'
        if (self.vbr_method == 3):
            return (u'-V    %s' % self.vbr_quality)
        elif (self.vbr_method in (4, 5)):
            return (u'-V    %s    --vbr-new' % self.vbr_quality)
    elif (version == (3, 98)):
        if (self.vbr_method == 3):
            return (u'-V    %s    --vbr-old' % self.vbr_quality)
        elif (self.vbr_method in (4, 5)):
            return (u'-V    %s' % self.vbr_quality)
    elif (version >= (3, 99)):
        if (self.vbr_method == 3):
            return (u'-V    %s    --vbr-old' % self.vbr_quality)
        elif (self.vbr_method in (4, 5)):
            p = self.vbr_quality
            adjust_key = (p, self.bitrate, self.lowpass_filter)
            p = {(5, 32, 0): 7, (5, 8, 0): 8, (6, 8, 0): 9}.get(adjust_key, p)
            return (u'-V    %s' % p)
    return u''
