add header Node

.gitignore

@@ -6,3 +6,4 @@ ffmpeg/tests/sample_data/out*.mp4
 ffmpeg_python.egg-info/
 venv*
 build/
+*pyc

.vscode/settings.json

@@ -0,0 +1,5 @@
+{
+    "python.linting.pylintEnabled": false,
+    "python.linting.pep8Enabled": true,
+    "python.linting.enabled": true
+}

ffmpeg/_ffmpeg.py

@@ -6,6 +6,7 @@ from ._utils import basestring
 from .nodes import (
     filter_operator,
     GlobalNode,
+    HeaderNode,
     InputNode,
     MergeOutputsNode,
     OutputNode,
@@ -13,7 +14,7 @@ from .nodes import (
 )
 
 
-def input(filename, **kwargs):
+def input(filename, *stream, **kwargs):
     """Input file URL (ffmpeg ``-i`` option)
 
     Any supplied kwargs are passed to ffmpeg verbatim (e.g. ``t=20``,
@@ -29,7 +30,13 @@ def input(filename, **kwargs):
         if 'format' in kwargs:
             raise ValueError("Can't specify both `format` and `f` kwargs")
         kwargs['format'] = fmt
-    return InputNode(input.__name__, kwargs=kwargs).stream()
+    return InputNode(input.__name__, stream=stream, kwargs=kwargs).stream()
+
+
+def header(**kwargs):
+    """Add extra header command-line argument(s), e.g. ``-re``.
+    """
+    return HeaderNode(header.__name__, kwargs=kwargs).stream()
 
 
 @output_operator()
@@ -94,4 +101,4 @@ def output(*streams_and_filename, **kwargs):
     return OutputNode(streams, output.__name__, kwargs=kwargs).stream()
 
 
-__all__ = ['input', 'merge_outputs', 'output', 'overwrite_output']
+__all__ = ['header', 'input', 'merge_outputs', 'output', 'overwrite_output']

ffmpeg/_run.py

@@ -13,6 +13,7 @@ from .nodes import (
     get_stream_spec_nodes,
     FilterNode,
     GlobalNode,
+    HeaderNode,
     InputNode,
     OutputNode,
     output_operator,
@@ -53,8 +54,8 @@ def _format_input_stream_name(stream_name_map, edge, is_final_arg=False):
     else:
         suffix = ':{}'.format(edge.upstream_selector)
     if is_final_arg and isinstance(edge.upstream_node, InputNode):
-        ## Special case: `-map` args should not have brackets for input
+        # Special case: `-map` args should not have brackets for input
-        ## nodes.
+        # nodes.
         fmt = '{}{}'
     else:
         fmt = '[{}{}]'
@@ -153,12 +154,14 @@ def get_args(stream_spec, overwrite_output=False):
     args = []
     # TODO: group nodes together, e.g. `-i somefile -r somerate`.
     sorted_nodes, outgoing_edge_maps = topo_sort(nodes)
+    header_nodes = [node for node in sorted_nodes if isinstance(node, HeaderNode)]
     input_nodes = [node for node in sorted_nodes if isinstance(node, InputNode)]
     output_nodes = [node for node in sorted_nodes if isinstance(node, OutputNode)]
     global_nodes = [node for node in sorted_nodes if isinstance(node, GlobalNode)]
     filter_nodes = [node for node in sorted_nodes if isinstance(node, FilterNode)]
     stream_name_map = {(node, None): str(i) for i, node in enumerate(input_nodes)}
     filter_arg = _get_filter_arg(filter_nodes, outgoing_edge_maps, stream_name_map)
+    args += reduce(operator.add, [_get_global_args(node) for node in header_nodes], [])
     args += reduce(operator.add, [_get_input_args(node) for node in input_nodes])
     if filter_arg:
         args += ['-filter_complex', filter_arg]

ffmpeg/nodes.py

@@ -235,7 +235,7 @@ class Node(KwargReprNode):
 class FilterableStream(Stream):
     def __init__(self, upstream_node, upstream_label, upstream_selector=None):
         super(FilterableStream, self).__init__(
-            upstream_node, upstream_label, {InputNode, FilterNode}, upstream_selector
+            upstream_node, upstream_label, {HeaderNode, InputNode, FilterNode}, upstream_selector
         )
 
 
@@ -243,11 +243,11 @@ class FilterableStream(Stream):
 class InputNode(Node):
     """InputNode type"""
 
-    def __init__(self, name, args=[], kwargs={}):
+    def __init__(self, name, stream: Stream = None, args=[], kwargs={}):
         super(InputNode, self).__init__(
-            stream_spec=None,
+            stream_spec=stream,
             name=name,
-            incoming_stream_types={},
+            incoming_stream_types={FilterableStream},
             outgoing_stream_type=FilterableStream,
             min_inputs=0,
             max_inputs=0,
@@ -343,6 +343,23 @@ class MergeOutputsNode(Node):
 
 
 # noinspection PyMethodOverriding
+class HeaderNode (Node):
+
+    def __init__(self, name: str = None, args=[], kwargs={}):
+        super(HeaderNode, self).__init__(
+            stream_spec=None,
+            name=name,
+            incoming_stream_types={},
+            outgoing_stream_type=FilterableStream,
+            min_inputs=0,
+            max_inputs=0,
+            args=args,
+            kwargs=kwargs,
+        )
+
+# noinspection PyMethodOverriding
+
+
 class GlobalNode(Node):
     def __init__(self, stream, name, args=[], kwargs={}):
         super(GlobalNode, self).__init__(

ffmpeg/tests/test_ffmpeg.py

@@ -135,6 +135,20 @@ def test_global_args():
     ]
 
 
+def test_header_args():
+    out_file = (
+        ffmpeg.header(thread_queue_size='512')
+        .input("input.mp4")
+        .output("output.mp4")
+    )
+    assert out_file.get_args() == [
+        '-thread_queue_size=512',
+        '-i',
+        'input.mp4',
+        'output.mp4',
+    ]
+
+
 def _get_simple_example():
     return ffmpeg.input(TEST_INPUT_FILE1).output(TEST_OUTPUT_FILE1)
 

requirements.txt

@@ -1,6 +1,7 @@
 alabaster==0.7.12
 atomicwrites==1.3.0
 attrs==19.1.0
+autopep8==1.4.4
 Babel==2.7.0
 certifi==2019.3.9
 chardet==3.0.4