Detect station if both lie within 1kHz of each other
This eliminates some artifacts being detected
Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc>
---
libavradio/sdrdemux.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/libavradio/sdrdemux.c b/libavradio/sdrdemux.c
index 4c1ec7b51c..bed74ebd26 100644
--- a/libavradio/sdrdemux.c
+++ b/libavradio/sdrdemux.c
@@ -855,13 +855,17 @@ static int probe_fm(SDRContext *sdr)
for (int pass = 0; pass < 2; pass ++) {
double avg[2] = {0}, tri = 0;
+ double mean = 0;
+ double center = 0;
for (i = 0; i<half_bw_i; i++) {
avg[0] += sdr->len2block[i];
tri += i*sdr->len2block[i];
}
+ mean = tri;
for (; i<2*half_bw_i; i++) {
avg[1] += sdr->len2block[i];
tri += (2*half_bw_i-i)*sdr->len2block[i];
+ mean += i*sdr->len2block[i];
}
for(i = half_bw_i; i<2*sdr->block_size - half_bw_i; i++) {
@@ -871,6 +875,10 @@ static int probe_fm(SDRContext *sdr)
b += avg[1];
tri += avg[1] - avg[0];
+ mean += (i+half_bw_i)*sdr->len2block[i+half_bw_i];
+ center = mean / b;
+ mean -= (i-half_bw_i)*sdr->len2block[i-half_bw_i];
+
if (i < border_i || i > 2*sdr->block_size - border_i)
continue;
@@ -884,6 +892,7 @@ static int probe_fm(SDRContext *sdr)
if (last_score[1] >= last_score[0] &&
last_score[1] > last_score[2] &&
last_score[1] > sdr->fm_threshold) {
+ double score = last_score[1];
float rmax = max_in_range(sdr, i-half_bw_i/4,
i+half_bw_i/4);
int lowcount = countbelow(sdr, i-half_bw_i/4,
i+half_bw_i/4, rmax / 100);
@@ -898,7 +907,12 @@ static int probe_fm(SDRContext *sdr)
if (peak_i < 0)
continue;
av_assert0(fabs(peak_i-i) < 2);
- create_candidate_station(sdr, FM, peak_i * 0.5 *
sdr->sdr_sample_rate / sdr->block_size + sdr->block_center_freq -
sdr->sdr_sample_rate/2, bandwidth_f, bandwidth_p2, last_score[1]);
+ double f = peak_i * 0.5 * sdr->sdr_sample_rate /
sdr->block_size + sdr->block_center_freq - sdr->sdr_sample_rate/2;
+ double f2 = center * 0.5 * sdr->sdr_sample_rate /
sdr->block_size + sdr->block_center_freq - sdr->sdr_sample_rate/2;
+
+ if (fabs(f2 - f) > 1000)
+ continue;
+ create_candidate_station(sdr, FM, f2, bandwidth_f,
bandwidth_p2, score);
}
}
}
--
2.31.1
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