audio gain, the best update since the rds upgrade

src/Makefile

@@ -62,7 +62,7 @@ LDFLAGS_Pissb	= $(LDFLAGS) -lsndfile -lliquid
 	$(CC) $(CFLAGS) -c -o pifmrds/waveforms.o pifmrds/waveforms.c
 #	$(CC) $(CFLAGS) -c -o pifmrds/rds_wav.o pifmrds/rds_wav.c
 	$(CC) $(CFLAGS) -c -o pifmrds/fm_mpx.o pifmrds/fm_mpx.c
-	$(CC) -o pifmrds/rds_wav pifmrds/rds_wav.o pifmrds/rds.o pifmrds/waveforms.o pifmrds/fm_mpx.o -lm -lsndfile
+	#$(CC) -o pifmrds/rds_wav pifmrds/rds_wav.o pifmrds/rds.o pifmrds/waveforms.o pifmrds/fm_mpx.o -lm -lsndfile
 	$(CXX) $(CXXFLAGS) -Wno-write-strings -o ../pifmrds pifmrds/rds.o pifmrds/waveforms.o pifmrds/pi_fm_rds.cpp pifmrds/fm_mpx.o pifmrds/control_pipe.o -lm -lsndfile -lrt -lpthread -L/opt/vc/lib -lrpitx
 
 ../rpitx: rpitxv1/rpitx.cpp 

src/pifmrds/fm_mpx.c

@@ -81,7 +81,7 @@ float *alloc_empty_buffer(size_t length) {
 }
 
 
-int fm_mpx_open(char *filename, size_t len, int raw, double preemphasis, int rawSampleRate, int rawChannels, float cutoff_freq) {
+int fm_mpx_open(char *filename, size_t len, int raw, double preemphasis, int rawSampleRate, int rawChannels, float cutoff_freq, float gain) {
     length = len;
     raw_ = raw;
 
@@ -131,7 +131,6 @@ int fm_mpx_open(char *filename, size_t len, int raw, double preemphasis, int raw
 
         // Create the low-pass FIR filter, with pre-emphasis
         double window, firlowpass, firpreemph , sincpos;
-        double gain=FIR_PHASES/25.0; // Why??? Maybe gain adjustment for preemphais
 
         // IIR pre-emphasis filter
         // Reference material:    http://jontio.zapto.org/hda1/preempiir.pdf
@@ -166,7 +165,7 @@ int fm_mpx_open(char *filename, size_t len, int raw, double preemphasis, int raw
           }
         }
     
-        printf("Created low-pass FIR filter for audio channels, with cutoff at %.1f Hz\n", cutoff_freq);
+        printf("Created low-pass FIR filter for audio channels, with cutoff at %.1f Hz (gain: %.f\n", cutoff_freq, gain);
     
         if( 0 )
         {

src/pifmrds/fm_mpx.h

@@ -21,6 +21,6 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-extern int fm_mpx_open(char *filename, size_t len, int raw, double preemphasis, int rawSampleRate, int rawChannels, float cutoff_freq);
+extern int fm_mpx_open(char *filename, size_t len, int raw, double preemphasis, int rawSampleRate, int rawChannels, float cutoff_freq, float gain);
 extern int fm_mpx_get_samples(float *mpx_buffer, int drds);
 extern int fm_mpx_close();

src/pifmrds/pi_fm_rds.cpp

@@ -87,7 +87,7 @@ static volatile void *map_peripheral(uint32_t base, uint32_t len)
     return vaddr;
 }
 
-int tx(uint32_t carrier_freq, char *audio_file, uint16_t pi, char *ps, char *rt, float ppm, char *control_pipe, int pty, int *af_array, int raw, int drds, double preemp, int power, int rawSampleRate, int rawChannels, int deviation, int ta, int tp, float cutoff_freq) {
+int tx(uint32_t carrier_freq, char *audio_file, uint16_t pi, char *ps, char *rt, float ppm, char *control_pipe, int pty, int *af_array, int raw, int drds, double preemp, int power, int rawSampleRate, int rawChannels, int deviation, int ta, int tp, float cutoff_freq, float gaim) {
     // Catch all signals possible - it is vital we kill the DMA engine
     // on process exit!
     for (int i = 0; i < 64; i++) {
@@ -110,7 +110,7 @@ int tx(uint32_t carrier_freq, char *audio_file, uint16_t pi, char *ps, char *rt,
     int data_index = 0;
 
     // Initialize the baseband generator
-    if(fm_mpx_open(audio_file, DATA_SIZE, raw, preemp, rawSampleRate, rawChannels, cutoff_freq) < 0) return 1;
+    if(fm_mpx_open(audio_file, DATA_SIZE, raw, preemp, rawSampleRate, rawChannels, cutoff_freq, gaim) < 0) return 1;
 
     // Initialize the RDS modulator
     char myps[9] = {0};
@@ -222,6 +222,7 @@ int main(int argc, char **argv) {
     int raw = 0;
     int drds = 0;
     int power = 7;
+    float gain = 1;
     int rawSampleRate = 44100;
     int rawChannels = 2;
     double preemp = 50e-6; //eu
@@ -298,9 +299,12 @@ int main(int argc, char **argv) {
         } else if(strcmp("-rawsamplerate", arg)==0 && param != NULL) {
             i++;
             rawSampleRate = atoi(param);
-	} else if(strcmp("-cutofffreq", arg)==0 && param != NULL) {
+        } else if(strcmp("-cutofffreq", arg)==0 && param != NULL) {
+                i++;
+                cutofffreq = atoi(param);
+        } else if(strcmp("-audiogain", arg)==0 && param != NULL) {
             i++;
-            cutofffreq = atoi(param);
+            gain = atoi(param);
         } else if(strcmp("-power", arg)==0 && param != NULL) {
             i++;
             int tpower = atoi(param);
@@ -343,6 +347,6 @@ int main(int argc, char **argv) {
     alternative_freq[0] = af_size;
     int FifoSize=DATA_SIZE*2;
     fmmod=new ngfmdmasync(carrier_freq,228000,14,FifoSize, false, gpiopin);
-    int errcode = tx(carrier_freq,  audio_file, pi, ps, rt, ppm, control_pipe, pty, alternative_freq, raw, drds, preemp, power, rawSampleRate, rawChannels, deviation, ta, tp, cutofffreq);
+    int errcode = tx(carrier_freq,  audio_file, pi, ps, rt, ppm, control_pipe, pty, alternative_freq, raw, drds, preemp, power, rawSampleRate, rawChannels, deviation, ta, tp, cutofffreq, gain);
     terminate(errcode);
 }