drwanghan
diff --git a/‎ffmpeg/_ffmpeg.py
Lines changed: 0 additions & 11 deletions b/‎ffmpeg/_ffmpeg.py
Lines changed: 0 additions & 11 deletions
diff --git a/‎ffmpeg/_run.py
Lines changed: 6 additions & 8 deletions b/‎ffmpeg/_run.py
Lines changed: 6 additions & 8 deletions
diff --git a/‎ffmpeg/tests/test_ffmpeg.py
Lines changed: 16 additions & 12 deletions b/‎ffmpeg/tests/test_ffmpeg.py
Lines changed: 16 additions & 12 deletions
@@ -2,7 +2,6 @@
 
 from .nodes import (
     filter_operator,
-    GlobalNode,
     InputNode,
     MergeOutputsNode,
     OutputNode,
@@ -24,15 +23,6 @@ def input(filename, **kwargs):
     return InputNode(input.__name__, kwargs=kwargs).stream()
 
 
-@output_operator()
-def overwrite_output(stream):
-    """Overwrite output files without asking (ffmpeg ``-y`` option)
-
-    Official documentation: `Main options <https://ffmpeg.org/ffmpeg.html#Main-options>`__
-    """
-    return GlobalNode(stream, overwrite_output.__name__).stream()
-
-
 @output_operator()
 def merge_outputs(*streams):
     """Include all given outputs in one ffmpeg command line
@@ -60,5 +50,4 @@ def output(stream, filename, **kwargs):
     'input',
     'merge_outputs',
     'output',
-    'overwrite_output',
 ]
@@ -10,7 +10,6 @@
 from ._ffmpeg import (
     input,
     output,
-    overwrite_output,
 )
 from .nodes import (
     get_stream_spec_nodes,
@@ -83,10 +82,7 @@ def _get_filter_arg(filter_nodes, outgoing_edge_maps, stream_name_map):
 
 
 def _get_global_args(node):
-    if node.name == overwrite_output.__name__:
-        return ['-y']
-    else:
-        raise ValueError('Unsupported global node: {}'.format(node))
+    raise ValueError('Unsupported global node: {}'.format(node))
 
 
 def _get_output_args(node, stream_name_map):
@@ -109,7 +105,7 @@ def _get_output_args(node, stream_name_map):
 
 
 @output_operator()
-def get_args(stream_spec, overwrite_output=False):
+def get_args(stream_spec, overwrite_output=True):
     """Get command-line arguments for ffmpeg."""
     nodes = get_stream_spec_nodes(stream_spec)
     args = []
@@ -126,7 +122,9 @@ def get_args(stream_spec, overwrite_output=False):
         args += ['-filter_complex', filter_arg]
     args += reduce(operator.add, [_get_output_args(node, stream_name_map) for node in output_nodes])
     args += reduce(operator.add, [_get_global_args(node) for node in global_nodes], [])
-    if overwrite_output:
+    if overwrite_output is False:
+        args += ['-n']
+    elif overwrite_output is not None:
         args += ['-y']
     return args
 
@@ -136,7 +134,7 @@ def run(stream_spec, cmd='ffmpeg', **kwargs):
     """Run ffmpeg on node graph.
 
-        **kwargs: keyword-arguments passed to ``get_args()`` (e.g. ``overwrite_output=True``).
+        **kwargs: keyword-arguments passed to ``get_args()`` (e.g. ``overwrite_output=False``).
     """
     if isinstance(cmd, basestring):
         cmd = [cmd]
 
@@ -101,7 +101,7 @@ def test_stream_repr():
 
 def test_get_args_simple():
     out_file = ffmpeg.input('dummy.mp4').output('dummy2.mp4')
-    assert out_file.get_args() == ['-i', 'dummy.mp4', 'dummy2.mp4']
+    assert out_file.get_args() == ['-i', 'dummy.mp4', 'dummy2.mp4', '-y']
 
 
 def _get_complex_filter_example():
@@ -122,7 +122,6 @@ def _get_complex_filter_example():
         .overlay(overlay_file.hflip())
         .drawbox(50, 50, 120, 120, color='red', thickness=5)
         .output(TEST_OUTPUT_FILE1)
-        .overwrite_output()
     )
 
 
@@ -156,7 +155,7 @@ def _get_drawtext_font_repr(font):
             .get_args()
         )
         assert args[:3] == ['-i', 'in', '-filter_complex']
-        assert args[4:] == ['-map', '[s0]', 'out']
+        assert args[4:] == ['-map', '[s0]', 'out', '-y']
         match = re.match(r'\[0\]drawtext=font=a((.|\n)*)b:text=test\[s0\]', args[3], re.MULTILINE)
         assert match is not None, 'Invalid -filter_complex arg: {!r}'.format(args[3])
         return match.group(1)
@@ -190,7 +189,7 @@ def _get_drawtext_text_repr(text):
             .get_args()
         )
-        assert args[4:] == ['-map', '[s0]', 'out']
+        assert args[4:] == ['-map', '[s0]', 'out', '-y']
         match = re.match(r'\[0\]drawtext=text=a((.|\n)*)b\[s0\]', args[3], re.MULTILINE)
         assert match is not None, 'Invalid -filter_complex arg: {!r}'.format(args[3])
         return match.group(1)
@@ -226,7 +225,7 @@ def test_run_multi_output():
     in_ = ffmpeg.input(TEST_INPUT_FILE1)
     out1 = in_.output(TEST_OUTPUT_FILE1)
     out2 = in_.output(TEST_OUTPUT_FILE2)
-    ffmpeg.run([out1, out2], overwrite_output=True)
+    ffmpeg.run([out1, out2])
 
 
 def test_run_dummy_cmd():
@@ -253,7 +252,8 @@ def test_custom_filter():
         '-i', 'dummy.mp4',
         '-filter_complex', '[0]custom_filter=a:b:kwarg1=c[s0]',
         '-map', '[s0]',
-        'dummy2.mp4'
+        'dummy2.mp4',
+        '-y',
     ]
 
 
@@ -267,7 +267,8 @@ def test_custom_filter_fluent():
         '-i', 'dummy.mp4',
         '-filter_complex', '[0]custom_filter=a:b:kwarg1=c[s0]',
         '-map', '[s0]',
-        'dummy2.mp4'
+        'dummy2.mp4',
+        '-y',
     ]
 
 
@@ -276,10 +277,10 @@ def test_merge_outputs():
     out1 = in_.output('out1.mp4')
     out2 = in_.output('out2.mp4')
     assert ffmpeg.merge_outputs(out1, out2).get_args() == [
-        '-i', 'in.mp4', 'out1.mp4', 'out2.mp4'
+        '-i', 'in.mp4', 'out1.mp4', 'out2.mp4', '-y'
     ]
     assert ffmpeg.get_args([out1, out2]) == [
-        '-i', 'in.mp4', 'out2.mp4', 'out1.mp4'
+        '-i', 'in.mp4', 'out2.mp4', 'out1.mp4', '-y'
     ]
 
 
@@ -292,14 +293,16 @@ def test_multi_passthrough():
         '-i', 'in2.mp4',
         'out1.mp4',
         '-map', '[1]',  # FIXME: this should not be here (see #23)
-        'out2.mp4'
+        'out2.mp4',
+        '-y',
     ]
     assert ffmpeg.get_args([out1, out2]) == [
         '-i', 'in2.mp4',
         '-i', 'in1.mp4',
         'out2.mp4',
         '-map', '[1]',  # FIXME: this should not be here (see #23)
-        'out1.mp4'
+        'out1.mp4',
+        '-y',
     ]
 
 
@@ -327,7 +330,8 @@ def test_pipe():
             '[0]trim=start_frame=2[s0]',
         '-map', '[s0]',
         '-f', 'rawvideo',
-        'pipe:1'
+        'pipe:1',
+        '-y',
     ]
 
     cmd = ['ffmpeg'] + args