activate sstv for background decoding

csdr/chain/sstv.py

@@ -1,5 +1,5 @@
 from owrx.sstv import SstvParser
-from csdr.chain.demodulator import SecondaryDemodulator, FixedAudioRateChain
+from csdr.chain.demodulator import ServiceDemodulator
 from pycsdr.modules import FmDemod, Buffer
 from pycsdr.types import Format
 from csdrsstv.modules import SstvDecoder
@@ -7,7 +7,7 @@ from owrx.feature import FeatureDetector
 from typing import Optional
 
 
-class Sstv(SecondaryDemodulator, FixedAudioRateChain):
+class Sstv(ServiceDemodulator):
     def __init__(self):
         self.imageBuffer = Buffer(Format.CHAR)
         super().__init__([

owrx/modes.py

@@ -140,7 +140,14 @@ class Modes(object):
         DigitalMode("rtty170", "RTTY 45/170", underlying=["usb", "lsb"]),
         DigitalMode("rtty450", "RTTY 50N/450", underlying=["lsb", "usb"]),
         DigitalMode("rtty85", "RTTY 50N/85", underlying=["lsb", "usb"]),
-        DigitalMode("sstv", "SSTV", underlying=["usb", "lsb"], bandpass=Bandpass(1100, 2400)),
+        DigitalMode(
+            "sstv",
+            "SSTV",
+            underlying=["usb", "lsb"],
+            bandpass=Bandpass(1100, 2400),
+            requirements=["sstv"],
+            service=True
+        ),
         WsjtMode("ft8", "FT8"),
         WsjtMode("ft4", "FT4"),
         WsjtMode("jt65", "JT65"),

owrx/service/__init__.py

@@ -327,6 +327,9 @@ class ServiceHandler(SdrSourceEventClient):
         elif mod == "ism":
             from csdr.chain.rtl433 import Rtl433
             return Rtl433()
+        elif mod == "sstv":
+            from csdr.chain.sstv import Sstv
+            return Sstv()
 
         raise ValueError("unsupported service modulation: {}".format(mod))