Lookahead limiter (fixed latency)
A lookahead limiter - similar to the original Lookahead Limiter, but
with a constant latency of around 150ms and a reduacued maximum lookahead
time.
b ? a : b;
/* XXX
sig = fabs(in_1[pos]) > fabs(in_2[pos]) ? fabs(in_1[pos]) :
fabs(in_2[pos]);
*/
if (sig > max) {
const float rel = lin2db(sig) - limit;
if (rel / delay > peak / (float)peak_dist) {
peak_dist = delay;
peak = rel;
}
}
/* Incremenatlly approach the correct attenuation for the next peak */
atten -= (atten - peak) / (float)(peak_dist + 1);
if (peak_dist-- == 0) {
peak_dist = f_round(delay);
peak = 0.0f;
}
/* Cacluate the apropriate gain reduction and write it back into the
* buffer */
gain = amp_buffer[(buffer_pos - f_round(delay)) & (buffer_len - 1)];
amp_buffer[(buffer_pos - f_round(delay)) & (buffer_len - 1)] =
1.0f / db2lin(atten);
gain=1.0f / db2lin(atten);
buffer_write(out_1[pos], buffer[(2 * (buffer_pos + 1)) &
buffer_mask] * gain);
buffer_write(out_2[pos], buffer[(2 * (buffer_pos + 1)+1) &
buffer_mask] * gain);
/* Ensure that the signal really can't be over the limit */
#if 0
XXX FIXME XXX
if (out_1[pos] < -max) {
buffer_write(out_1[pos], -max);
} else if (out_1[pos] > max) {
buffer_write(out_1[pos], max);
}
if (out_2[pos] < -max) {
buffer_write(out_2[pos], -max);
} else if (out_2[pos] > max) {
buffer_write(out_2[pos], max);
}
#endif
buffer_pos++;
}
plugin_data->buffer_pos = buffer_pos;
plugin_data->peak = peak;
plugin_data->peak_dist = peak_dist;
plugin_data->atten = atten;
plugin_data->last_delay = delay;
*(plugin_data->attenuation) = atten;
*(plugin_data->latency) = buffer_len - 1;
]]>
buffer);
free(plugin_data->amp_buffer);
]]>
Limit (dB)
The maximum output amplitude. Peaks over this level will be attenuated as smoothly as possible to bring them as close as possible to this level.
Lookahead time (s)
The lookahead time used by the lookahead predictor. The longer the time the smoother the limiting will be, but will tend to make the changes in dynamic range more obvious.
Attenuation (dB)
The current limiting attenuation of the signal coming out of the delay
buffer.
Input 1
Input 2
Output 1
Output 2
latency