python 2/3 agnosticism sockaudio.py

op25/gr-op25_repeater/apps/sockaudio.py

@@ -29,6 +29,7 @@ import select
 import socket
 import errno
 import struct
+import numpy as np
 
 # OP25 defaults
 PCM_RATE = 8000			# audio sample rate (Hz)
@@ -169,7 +170,7 @@ class alsasound(object):
 
 		self.libasound.snd_pcm_hw_params_current(self.c_pcm, c_pars)
 		c_bits =  self.libasound.snd_pcm_hw_params_get_sbits(c_pars)
-		self.framesize = self.channels * c_bits/8
+		self.framesize = self.channels * c_bits//8
 
 		c_sw_pars = (c_void_p * int(self.libasound.snd_pcm_sw_params_sizeof() / sizeof(c_void_p)))()
 		err = self.libasound.snd_pcm_sw_params_current(self.c_pcm, c_sw_pars)
@@ -192,7 +193,7 @@ class alsasound(object):
 
 	def write(self, pcm_data):
 		datalen = len(pcm_data)
-		n_frames = c_ulong(datalen / self.framesize)
+		n_frames = c_ulong(datalen // self.framesize)
 		c_data = c_char_p(pcm_data)
 		ret = 0
 
@@ -293,14 +294,14 @@ class socket_audio(threading.Thread):
 			if in_a is not None:
 				len_a = len(in_a[0])
 				if len_a == 2:
-					flag_a = ord(in_a[0][0]) + (ord(in_a[0][1]) << 8)	# 16 bit little endian
+					flag_a = np.frombuffer(in_a[0], dtype=np.int16)[0]
 				elif len_a > 0:
 					data_a = in_a[0]
 
 			if in_b is not None:
 				len_b = len(in_b[0])
 				if len_b == 2:
-					flag_b = ord(in_b[0][0]) + (ord(in_b[0][1]) << 8)	# 16 bit little endian
+					flag_b = np.frombuffer(in_b[0], dtype=np.int16)[0]
 				elif len_b > 0:
 					data_b = in_b[0]
 
@@ -328,31 +329,24 @@ class socket_audio(threading.Thread):
 		self.close_pcm()
 		return
 
-	def scale(self, data):	# crude amplitude scaler (volume) for S16_LE samples
-		scaled_data = ""
-		d_len = len(data) / 2
-		iter_d = iter(data)
-		i = 0;
-		while i < d_len:
-			i += 1
-			pcm_r = struct.unpack('<h', next(iter_d, chr(0)) + next(iter_d, chr(0)))[0]
-			pcm_s = min(max((int)(pcm_r * self.audio_gain), -32768), 32767)
-			scaled_data += struct.pack('<h', pcm_s)
-		return scaled_data
+	def scale(self, data):
+		arr = np.array(np.frombuffer(data, dtype=np.int16), dtype=np.float32)
+		result = np.zeros(len(arr), dtype=np.int16)
+		arr = np.clip(arr*self.audio_gain, -32767, 32766, out=result)
+		return result.tobytes('C')
 
 	def interleave(self, data_a, data_b):
-		combi_data = ""
-		d_len = max(len(data_a), len(data_b))
-		iter_a = iter(data_a)
-		iter_b = iter(data_b)
-		i = 0
-		while i < d_len:
-			i += 2
-			combi_data += next(iter_a, chr(0))
-			combi_data += next(iter_a, chr(0))
-			combi_data += next(iter_b, chr(0))
-			combi_data += next(iter_b, chr(0))
-		return combi_data
+		arr_a = np.frombuffer(data_a, dtype=np.int16)
+		arr_b = np.frombuffer(data_b, dtype=np.int16)
+		d_len = max(len(arr_a), len(arr_b))
+		result = np.zeros(d_len*2, dtype=np.int16)
+		if len(arr_a):
+			# copy arr_a to result[0,2,4, ...]
+			result[ range(0, len(arr_a)*2, 2) ] = arr_a
+		if len(arr_b):
+			# copy arr_b to result[1,3,5, ...]
+			result[ range(1, len(arr_b)*2, 2) ] = arr_b
+		return result.tobytes('C')
 
 	def stop(self):
 		self.keep_running = False