Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc>
---
libavradio/sdrdemux.c | 35 ++++++++++++++++++++++++++++++++---
1 file changed, 32 insertions(+), 3 deletions(-)
diff --git a/libavradio/sdrdemux.c b/libavradio/sdrdemux.c
index fea4202709..fd3f5dd52d 100644
--- a/libavradio/sdrdemux.c
+++ b/libavradio/sdrdemux.c
@@ -383,6 +383,7 @@ static int create_candidate_station(SDRContext *sdr, enum
Modulation modulation,
Station *station_list[1000];
double snapdistance = modulation == AM ? AM_FREQ_TOLERANCE :
FM_FREQ_TOLERANCE;
int nb_stations = ff_sdr_find_stations(sdr, freq, snapdistance,
station_list, FF_ARRAY_ELEMS(station_list));
+ int update_freq = 1;
if (nb_stations) {
for(int i = 1; i<nb_stations; i++)
@@ -409,12 +410,18 @@ static int create_candidate_station(SDRContext *sdr, enum
Modulation modulation,
goto fail;
} else {
station = station_list[0];
+
+ //demodulated FM stations have their frequency computed exactly, so
dont mess them up
+ update_freq = station->modulation != FM || !station->in_station_list
|| !sdr->demodulate_all_fm;
+
// We will update the frequency so we need to reinsert
tree_remove(&sdr->station_root, station, station_cmp, &next);
- station->frequency = station->nb_frequency * station->frequency + freq;
+ if (update_freq)
+ station->frequency = station->nb_frequency * station->frequency +
freq;
station->timeout = 0;
}
- station->frequency /= ++station->nb_frequency;
+ if(update_freq)
+ station->frequency /= ++station->nb_frequency;
station->detection_per_mix_frequency[histogram_index(sdr, freq)] ++;
station->modulation = modulation;
@@ -934,6 +941,22 @@ static int probe_fm(SDRContext *sdr)
return 0;
}
+static void station_update_freq(SDRContext *sdr, Station *station, double freq)
+{
+ struct AVTreeNode *next = NULL;
+ void *tmp;
+
+ //We must reinsert the station if we change the key (frequency)
+ tree_remove(&sdr->station_root, station, station_cmp, &next);
+
+ station->frequency = station->nb_frequency * station->frequency + freq;
+ station->frequency /= ++station->nb_frequency;
+
+ tmp = tree_insert(&sdr->station_root, station, station_cmp, &next);
+ av_assert0(!tmp || tmp == station);
+ av_freep(&next);
+}
+
static int demodulate_fm(SDRContext *sdr, Station *station, AVStream *st,
AVPacket *pkt)
{
SDRStream *sst = st ? st->priv_data : NULL;
@@ -953,11 +976,12 @@ static int demodulate_fm(SDRContext *sdr, Station
*station, AVStream *st, AVPack
int len2_4_i = 2L*sdr->fm_block_size* 2400 / sample_rate;
double carrier19_i_exact;
int W= 5;
+ double dc = 0, dcw = 0;
+ int len2 = FFMIN(index, 2*sdr->block_size - index);
av_assert0(!st || (sst == station->stream && sst->station == station));
//If only some of the bandwidth is available, just try with less
- int len2 = FFMIN(index, 2*sdr->block_size - index);
if (len2 < len && len2 > len/2)
len = len2;
@@ -979,9 +1003,14 @@ static int demodulate_fm(SDRContext *sdr, Station
*station, AVStream *st, AVPack
sdr->fm_iblock[i].re = atan2(x.im * y.re - x.re * y.im,
x.re * y.re + x.im * y.im) *
sdr->fm_window[i];
sdr->fm_iblock[i].im = 0;
+ dc += sdr->fm_iblock[i].re;
+ dcw+= sdr->fm_window[i] * sdr->fm_window[i];
}
sdr->fm_iblock[i].re = 0;
sdr->fm_iblock[i].im = 0;
+ dc *= M_PI/2 * sqrt((2*sdr->fm_block_size - 1) / dcw);
+
+ station_update_freq(sdr, station, freq-dc);
av_assert0(sdr->fm_block_size_p2 * 2 < sdr->fm_block_size);
//FIXME this only needs to be a RDFT
--
2.31.1
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