Merge pull request #501 from happycube/i492a

add deemp adjustment

ld-decode

@@ -39,6 +39,7 @@ parser.add_argument('--verboseVITS', dest='verboseVITS', action='store_true', de
 
 parser.add_argument('--lowband', dest='lowband', action='store_true', default=False, help='Use more restricted RF settings for noisier disks')
 parser.add_argument('--WibbleRemover', dest='WibbleRemover', action='store_true', default=False, help='PAL/digital sound: (try to) remove spurious ~8.5mhz signal. Mitigate interference from analog audio in reds on NTSC')
+parser.add_argument('-d', '--deemp_adjust', metavar='deemp_adjust', type=float, default=1.0, help='mtf compensation multiplier')
 
 parser.add_argument('-t', '--threads', metavar='threads', type=int, default=5, help='number of CPU threads to use')
 
@@ -59,7 +60,7 @@ if args.pal and args.ntsc:
     print("ERROR: Can only be PAL or NTSC")
     exit(1)
 
-extra_options = {'useAGC': not args.noAGC}
+extra_options = {'useAGC': not args.noAGC, 'deemp_level': (args.deemp_adjust, args.deemp_adjust)}
 
 if args.WibbleRemover:
     extra_options['WibbleRemover'] = True

lddecode/core.py

@@ -329,6 +329,10 @@ def __init__(self, inputfreq = 40, system = 'NTSC', blocklen = 32*1024, decode_d
 
         self.SysParams['analog_audio'] = has_analog_audio
 
+        self.deemp_level = extra_options.get('deemp_level')
+        if self.deemp_level is None:
+            self.deemp_level = (1.0, 1.0)
+
         linelen = self.freq_hz/(1000000.0/self.SysParams['line_period'])
         self.linelen = int(np.round(linelen))
         # How much horizontal sync position can deviate from previous/expected position 
@@ -454,6 +458,8 @@ def computevideofilters(self):
 
         # The deemphasis filter
         deemp1, deemp2 = DP['video_deemp']
+        deemp1 *= self.deemp_level[0]
+        deemp2 *= self.deemp_level[1]
         SF['Fdeemp'] = filtfft(emphasis_iir(deemp1, deemp2, self.freq_hz), self.blocklen)
 
         # The direct opposite of the above, used in test signal generation

lddecode/plot_utils.py

@@ -168,6 +168,10 @@ def draw_raw_bwimage(bm, x = 2800, y = 525, hscale = 1, vscale = 2, outsize = No
 def draw_field(field):
     return draw_raw_bwimage(field.dspicture, field.outlinelen, field.outlinecount)
 
+def plotline(field, line):
+	ls = field.lineslice(line, 0, 63.5)
+	plt.plot(field.data['video']['demod'][ls])
+
 class RGBoutput:
     def __init__(self, outname):
         try:

notebooks/devbook_base.ipynb

@@ -90,7 +90,7 @@
    "source": [
     "# Would move this to uitls, but needs to run core.LDdecode\n",
     "\n",
-    "def rundecode(filename, outname, firstframe, numframes, system='NTSC'):\n",
+    "def rundecode(filename, outname, firstframe, numframes, system='NTSC', extra_options = {}):\n",
     "    \"\"\" Helper function for notebooks, returns main ldd object and all fields \"\"\"\n",
     "    loader = make_loader(filename)\n",
     "\n",