Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc>
---
libavradio/sdrdemux.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/libavradio/sdrdemux.c b/libavradio/sdrdemux.c
index 54d7622809..b69b13d075 100644
--- a/libavradio/sdrdemux.c
+++ b/libavradio/sdrdemux.c
@@ -67,7 +67,7 @@
#define AM_MAX4 0.02
//Least squares fit at 1khz points of frequency response shown by Frank
McClatchie, FM SYSTEMS, INC. 800-235-6960
-static double emphasis75us(int f)
+static double emphasis75us(double f)
{
return ((((((((- 4.79546E-9 * f + 5.32101E-7) * f - 0.0000254577) * f +
0.000687225) * f
- 0.0114925) * f + 0.122781 ) * f - 0.827885 ) * f +
3.25025 ) * f - 4.6049) * f + 2.06937;
@@ -76,15 +76,16 @@ static double emphasis75us(int f)
/**
* Apply emphasis filter in frequency domain
*/
-static void apply_deemphasis(SDRContext *sdr, AVComplexFloat *data, int len,
int sample_rate, int dir)
+static void apply_deemphasis(SDRContext *sdr, AVComplexFloat *data, int len,
int block_size, int sample_rate, int dir)
{
+ double factor = sample_rate / (2000.0*block_size);
if (sdr->emphasis_mode == EMPHASIS_NONE)
return;
- len = FFMIN(len, len * 19000 / sample_rate);
+ len = FFMIN(len, len * 2 * 19000 / sample_rate);
for (int i = 1; i < len; i++) {
- double index = 1.0 + i / 1000;
+ double index = 1.0 + i * factor;
double scale;
if (sdr->emphasis_mode == EMPHASIS_50us)
@@ -1051,8 +1052,8 @@ static int demodulate_fm(SDRContext *sdr, Station
*station, AVStream *st, AVPack
if (st) {
memcpy(sdr->fm_block + i, sdr->fm_block + 2*carrier19_i,
sizeof(AVComplexFloat)*len17_i);
memcpy(sdr->fm_block + i + 2*sdr->fm_block_size_p2 - len17_i,
sdr->fm_block + 2*carrier19_i - len17_i, sizeof(AVComplexFloat)*len17_i);
- apply_deemphasis(sdr, sdr->fm_block + i, sdr->fm_block_size_p2,
sample_rate_p2, + 1);
- apply_deemphasis(sdr, sdr->fm_block + i + 2*sdr->fm_block_size_p2,
sdr->fm_block_size_p2, sample_rate_p2, - 1);
+ apply_deemphasis(sdr, sdr->fm_block + i, sdr->fm_block_size_p2,
sdr->fm_block_size_p2, sample_rate_p2, + 1);
+ apply_deemphasis(sdr, sdr->fm_block + i + 2*sdr->fm_block_size_p2,
sdr->fm_block_size_p2, sdr->fm_block_size_p2, sample_rate_p2, - 1);
sdr->fm_ifft_p2(sdr->fm_ifft_p2_ctx, sdr->fm_iside ,
sdr->fm_block + i, sizeof(AVComplexFloat));
synchronous_am_demodulationN(sdr->fm_iside, sdr->fm_icarrier,
sdr->fm_window_p2, 2*sdr->fm_block_size_p2, 2);
}
@@ -1061,7 +1062,7 @@ static int demodulate_fm(SDRContext *sdr, Station
*station, AVStream *st, AVPack
return 0;
memset(sdr->fm_block + len17_i, 0, (2*sdr->fm_block_size_p2 - len17_i) *
sizeof(AVComplexFloat));
- apply_deemphasis(sdr, sdr->fm_block, 2*sdr->fm_block_size_p2,
sample_rate_p2, + 1);
+ apply_deemphasis(sdr, sdr->fm_block, sdr->fm_block_size_p2,
sdr->fm_block_size_p2, sample_rate_p2, + 1);
sdr->fm_ifft_p2(sdr->fm_ifft_p2_ctx, sdr->fm_iblock , sdr->fm_block,
sizeof(AVComplexFloat));
memset(sdr->fm_iblock + 2*sdr->fm_block_size_p2, 0 ,(2*sdr->fm_block_size
-2*sdr->fm_block_size_p2) * sizeof(AVComplexFloat));
--
2.31.1
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