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Make Analog Auto Gain Control Mostly Tolerable;

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lwvmobile
2024-03-22 20:11:34 -04:00
parent 2f9e0525fe
commit e549b21497
4 changed files with 31 additions and 36 deletions
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61
src/dsd_audio2.c
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@@ -1352,58 +1352,47 @@ void agf (dsd_opts * opts, dsd_state * state, float samp[160], int slot)
//automatic gain short mono for analog audio and some digital mono (WIP)
void agsm (dsd_opts * opts, dsd_state * state, short * input, int len)
{
int i, j;
int i;
UNUSED(state);
UNUSED(opts);
//NOTE: This seems to be doing better now that I got it worked out properly
//This may produce a mild buzz sound though on the low end
float avg = 0.0f; //average of 20 samples
float coeff = 0.0f; //gain coeffiecient
float max = 0.0f; //the highest sample value
float nom = 1500.0f; //nominator value
float gain = (25.0f / opts->audio_gain); UNUSED(gain);
float nom = 4800.0f; //nominator value for 48k
float samp[960]; memset (samp, 0.0f, 960*sizeof(float));
//assign internal float from short input
for (i = 0; i < len; i++)
samp[i] = (float)input[i];
// gain = 2.5f;
// for (i = 0; i < len; i++)
// samp[i] *= gain;
for (j = 0; j < len/20; j++)
for (i = 0; i < len; i++)
{
for (i = 0; i < 20; i++)
if ( fabsf (samp[i]) > max)
{
if ( fabsf (samp[(j*20)+i]) > max)
{
max = fabsf (samp[(j*20)+i]);
}
max = fabsf (samp[i]);
}
}
for (i = 0; i < 20; i++)
avg += (float)samp[(j*20)+i];
for (i = 0; i < len; i++)
avg += (float)samp[i];
avg /= 20;
avg /= (float)len;
coeff = fabsf (nom / max);
//keep coefficient with tolerable range when silence to prevent crackle/buzz
if (coeff > 3.0f) coeff = 3.0f;
//apply the coefficient to bring the max value to our desired maximum value
for (i = 0; i < 20; i++)
samp[i] *= coeff;
coeff = fabsf (nom / max);
//apply the coefficient to bring the max value to our desired maximum value
for (i = 0; i < 20; i++)
{
if ( fabsf (samp[(j*20)+i]) > 110.0f) //try not to apply to near zero values
samp[(j*20)+i] *= coeff;
}
//debug
// fprintf (stderr, "\n M: %f; C: %f; A: %f; ", max, coeff, avg);
max = 0; //reset
avg = 0; //reset
} //end j loop
//debug
// fprintf (stderr, "\n M: %f; C: %f; A: %f; ", max, coeff, avg);
// debug
// for (i = 0; i < len; i++)
@@ -1416,6 +1405,8 @@ void agsm (dsd_opts * opts, dsd_state * state, short * input, int len)
for (i = 0; i < len; i++)
input[i] = (short)samp[i];
state->aout_gainA = coeff; //store for internal use
}
//until analog agc is fixed, going to use a manual gain control on this