split out for_duration as for_stream(s) and for_format

marm/ffmpeg.py

@@ -252,11 +252,25 @@ def for_first_frame(cls, *args, **kwargs):
         return n
 
     @classmethod
-    def for_duration(cls, *args, **kwargs):
+    def for_format_duration(cls, *args, **kwargs):
         probe = cls(['-show_format'] + list(args), **kwargs)
         probe()
         return timedelta(seconds=probe.result['format']['duration'])
 
+    @classmethod
+    def for_stream_durations(cls, *args, **kwargs):
+        probe = cls(['-show_streams'] + list(args), **kwargs)
+        probe()
+        return [
+            timedelta(seconds=s['duration']) for s in probe.result['streams']
+        ]
+
+    @classmethod
+    def for_stream_duration(cls, *args, **kwargs):
+        probe = cls(['-show_streams'] + list(args), **kwargs)
+        probe()
+        return max(cls.for_stream_durations(*args, **kwargs) + [timedelta()])
+
     @classmethod
     def for_streams(cls, *args, **kwargs):
         probe = cls(['-show_streams'] + list(args), **kwargs)

test/test_ff_wrapper.py

@@ -1,3 +1,5 @@
+from datetime import timedelta
+
 import pytest
 
 import marm
@@ -41,3 +43,20 @@ def test_ffprobe_last_packet(fixtures, file_name, args, as_fo, expected):
     else:
         r = marm.FFProbe.for_last_packet(*(args + [p.strpath]))
     assert r == expected
+
+
+@pytest.mark.parametrize(
+    'file_name,expected_stream,expected_format', [
+        ('sonic.ts',
+         timedelta(seconds=120.033333),
+         timedelta(seconds=120.054667)),
+    ]
+)
+def test_ffprobe_duration(
+        fixtures,
+        file_name,
+        expected_stream,
+        expected_format):
+    p = fixtures.join(file_name)
+    assert marm.FFProbe.for_stream_duration(p.strpath) == expected_stream
+    assert marm.FFProbe.for_format_duration(p.strpath) == expected_format