iridium-extractor: add generate-sigmf-meta feature (#207)

.github/workflows/ci.yml

@@ -85,6 +85,15 @@ jobs:
          ln -s prbs15-2M-20dB.sigmf-data test-data/prbs15-2M-20dB.fc32
          iridium-extractor --offline -c 1622000000 -r 2000000 -f float test-data/prbs15-2M-20dB.fc32 |grep ^RAW > prbs15-2M-20dB.bits.raw
          grep "RAW: prbs15-2M-20dB 0000599.9996 1622000000 N:32.12-80.05 I:00000000000 100% 0.13551 179 0011000000110000111100111000000000000011000000000000101000000000001111000000000010001000000000110011000000001010101000000011111111000000100000001000001100000011000010100000101000111100001111001000100010001011001100110011101010101010100111111111111101000000000000111000000000001001000000000011011000000000101101000000001110111000000010011001000000110101011000001011111101000011100000" prbs15-2M-20dB.bits.raw
+      - name: Test osmocom_fft names
+        run: |
+         ln -s prbs15-2M-20dB.sigmf-data test-data/prbs-f1.622000e+09-s2.000000e+06-t20240524014205+0200.cfile
+         iridium-extractor --offline test-data/prbs-f1.622000e+09-s2.000000e+06-t20240524014205+0200.cfile |grep ^RAW > prbs15-2M-20dB.bits.offt
+         grep "RAW: i-1716507725-t1 0000599.9996 1622000000 N:32.12-80.05 I:00000000000 100% 0.13551 179 0011000000110000111100111000000000000011000000000000101000000000001111000000000010001000000000110011000000001010101000000011111111000000100000001000001100000011000010100000101000111100001111001000100010001011001100110011101010101010100111111111111101000000000000111000000000001001000000000011011000000000101101000000001110111000000010011001000000110101011000001011111101000011100000" prbs15-2M-20dB.bits.offt
+      - name: Test sigmf-meta generation
+        run: |
+         iridium-extractor --offline --generate-sigmf-meta prbs.sigmf-meta test-data/prbs-f1.622000e+09-s2.000000e+06-t20240524014205+0200.cfile > /dev/null
+         cmp prbs.sigmf-meta test-data/generated.sigmf-meta
       - name: Test SigMF Archive support
         run: |
          tar cf test-data/prbs15-2M-20dB.sigmf test-data/prbs15-2M-20dB.sigmf-*

README.md

@@ -283,6 +283,11 @@ This is mostly useful for debugging when using SDR mode to process live data.
 
 The samples will be written in `ci16_le` format.
 
+#### `--generate-sigmf-meta`: Create a sigm-meta file based on the input format
+additionally write a file in sigmf-meta format describing the processed input.
+
+To convert a standard recording to a sigmf dataset, specify "--generate-sigmf-meta NEWNAME.sigmf-meta" and then after the extractor ends, manually rename your recording to "NEWNAME.sigmf-data"
+
 ### Interactive Output
 During normal operation `iridium-extractor` will output a status line once per second on `stderr`.
 #### SDR / live mode

apps/iridium-extractor

@@ -149,6 +149,8 @@ if __name__ == "__main__":
                         help='Sample rate of the source or the file in Hz. Must be divisible by 100000.')
     parser.add_argument('--raw-capture', dest='raw_capture_filename', action="store",
                         help='Write a copy of the samples to a SigMF recording.')
+    parser.add_argument('--generate-sigmf-meta', dest='sigmf_meta_filename', action="store",
+                        help='Create a sigm-meta file based on the input format.')
     parser.add_argument('-v', '--verbose', dest='verbose', action='store_true',
                         help='Enable verbose output.')
 
@@ -337,6 +339,39 @@ if __name__ == "__main__":
             print("/tmp/signals directory missing!", file=sys.stderr)
             exit(1)
 
+    if args.sigmf_meta_filename is not None:
+        import json
+        import datetime
+        dt = None
+        if args.file_info is not None and (g := re.search(r"i-(\d+(\.\d+)?)-", args.file_info)):
+            try:
+                dt = datetime.datetime.fromtimestamp(float(g.group(1)), datetime.timezone.utc)
+            except ValueError:
+                pass
+        if dt is None:
+            dt = datetime.datetime.fromtimestamp(os.path.getctime(filename), datetime.timezone.utc)
+
+        data = {
+            'global': {
+                'core:datatype': fmt,
+                'core:description': 'autogenerated for ' + os.path.basename(filename),
+                'core:recorder': 'iridium-extractor',
+                "core:num_channels": 1,
+                'core:sample_rate': sample_rate,
+                'core:version': '1.0.0'
+            },
+            'captures': [
+                {
+                    'core:datetime': dt.astimezone(datetime.timezone.utc).replace(microsecond=0, tzinfo=None).isoformat() + 'Z',
+                    'core:frequency': center,
+                    'core:sample_start': 0
+                }
+            ]
+        }
+
+        with open(args.sigmf_meta_filename, 'w') as outfile:
+            json.dump(data, outfile, indent=4)
+
     if args.raw_capture_filename is not None:
         import json
         import datetime

test-data/generated.sigmf-meta

@@ -0,0 +1,17 @@
+{
+    "global": {
+        "core:datatype": "cf32_le",
+        "core:description": "autogenerated for prbs-f1.622000e+09-s2.000000e+06-t20240524014205+0200.cfile",
+        "core:recorder": "iridium-extractor",
+        "core:num_channels": 1,
+        "core:sample_rate": 2000000,
+        "core:version": "1.0.0"
+    },
+    "captures": [
+        {
+            "core:datetime": "2024-05-23T23:42:05Z",
+            "core:frequency": 1622000000,
+            "core:sample_start": 0
+        }
+    ]
+}