From ef13343925db655cea7284c7f33df1da9e0187d1 Mon Sep 17 00:00:00 2001
From: lwvmobile <lwvmobile@gmail.com>
Date: Tue, 19 Mar 2024 12:46:27 -0400
Subject: [PATCH] RTL_FM Input for Analog/M17 Encoder;

---
 src/m17.c          |  4 ++--
 src/rtl_sdr_fm.cpp | 30 ++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/src/m17.c b/src/m17.c
index b709b44..cb3f102 100644
--- a/src/m17.c
+++ b/src/m17.c
@@ -1855,8 +1855,8 @@ void encodeM17STR(dsd_opts * opts, dsd_state * state)
     //run lpf and hpf
     // lpf8 (state, voice1, 160);
     // lpf8 (state, voice2, 160);
-    hpf8 (state, voice1, 160);
-    hpf8 (state, voice2, 160);
+    // hpf (state, voice1, 160);
+    // hpf (state, voice2, 160);
 
     //convert out audio input into CODEC2 (3200bps) 8 byte data stream
     uint8_t vc1_bytes[8]; memset (vc1_bytes, 0, sizeof(vc1_bytes));
diff --git a/src/rtl_sdr_fm.cpp b/src/rtl_sdr_fm.cpp
index e571503..2762d47 100644
--- a/src/rtl_sdr_fm.cpp
+++ b/src/rtl_sdr_fm.cpp
@@ -815,6 +815,34 @@ void dongle_init(struct dongle_state *s)
 	s->demod_target = &demod;
 }
 
+void demod_init_analog(struct demod_state *s)
+{
+	s->rate_in = rtl_bandwidth;
+	s->rate_out = rtl_bandwidth;
+	s->squelch_level = 0;
+	s->conseq_squelch = 10;
+	s->terminate_on_squelch = 0;
+	s->squelch_hits = 11;
+	s->downsample_passes = 1; //
+	s->comp_fir_size = 0;
+	s->prev_index = 0;
+	s->post_downsample = 1;  //1 -- once this works, default = 4 -- doesn't work on the official rtl-sdr source code either
+	s->custom_atan = 0;
+	s->deemph = 1; //
+	s->rate_out2 = rtl_bandwidth;  // -1 flag for disabled -- this enables low_pass_real, seems to work okay
+	s->mode_demod = &fm_demod;
+	s->pre_j = s->pre_r = s->now_r = s->now_j = 0;
+	s->prev_lpr_index = 0;
+	s->deemph_a = 0; //
+	s->now_lpr = 0;
+	s->dc_block = 1; //
+	s->dc_avg = 0;
+	pthread_rwlock_init(&s->rw, NULL);
+	pthread_cond_init(&s->ready, NULL);
+	pthread_mutex_init(&s->ready_m, NULL);
+	s->output_target = &output;
+}
+
 void demod_init_ro2(struct demod_state *s)
 {
 	s->rate_in = rtl_bandwidth;
@@ -1005,6 +1033,8 @@ void open_rtlsdr_stream(dsd_opts *opts)
 	//init with low pass if decoding P25 or EDACS/Provoice
 	if (opts->frame_p25p1 == 1 || opts->frame_p25p2 == 1 || opts->frame_provoice == 1)
   	demod_init_ro2(&demod);
+	else if (opts->analog_only == 1 || opts->m17encoder == 1)
+		demod_init_analog(&demod);
 	else demod_init(&demod);
   output_init(&output);
   controller_init(&controller);