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Attempt to account for make-up-gain. Still not good ...

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Themaister 2012-02-25 04:51:01 +01:00
parent 5f330cbfa5
commit 2fba62867f
1 changed files with 19 additions and 5 deletions
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24
audio/test/snr.c
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@ -31,26 +31,40 @@ static void gen_signal(float *out, double freq, double sample_rate, double bias_
}
}
static double calculate_gain(const float *orig, const float *resamp, size_t samples)
{
double orig_power = 0.0;
double resamp_power = 0.0;
for (size_t i = 0; i < samples; i += 2)
orig_power += orig[i] * orig[i];
for (size_t i = 0; i < samples; i += 2)
resamp_power += resamp[i] * resamp[i];
return resamp_power / orig_power;
}
static double calculate_snr(const float *orig, const float *resamp, size_t samples)
{
double noise = 0.0;
double signal = 0.0;
double make_up_gain = 1.0 / calculate_gain(orig, resamp, samples);
for (size_t i = 0; i < samples; i += 2)
signal += orig[i] * orig[i];
for (size_t i = 0; i < samples; i += 2)
{
double diff = resamp[i] - orig[i];
double diff = make_up_gain * resamp[i] - orig[i];
noise += diff * diff;
}
double snr = 10 * log10(signal / noise);
return snr;
return 10.0 * log10(signal / noise);
}
#define SAMPLES 0x100000
#define SAMPLES 0x40000
// This approach is kinda stupid.
// There should be a good way to directly (and accurately) determine phase after correlating