From 63d660f1297ea0eec6b822f6f6552515f508cd24 Mon Sep 17 00:00:00 2001
From: Davide Depau <davide@depau.eu>
Date: Thu, 25 Jan 2018 12:25:20 +0100
Subject: [PATCH] Implement SourceNode

---
 ffmpeg/_ffmpeg.py | 35 ++++++++++++++++++++++++++++++--
 ffmpeg/_run.py    |  7 ++++---
 ffmpeg/nodes.py   | 51 +++++++++++++++++++++++++++++++----------------
 3 files changed, 71 insertions(+), 22 deletions(-)

diff --git a/ffmpeg/_ffmpeg.py b/ffmpeg/_ffmpeg.py
index 31e2b90..a7b038d 100644
--- a/ffmpeg/_ffmpeg.py
+++ b/ffmpeg/_ffmpeg.py
@@ -10,7 +10,7 @@ from .nodes import (
     MergeOutputsNode,
     OutputNode,
     output_operator,
-)
+    SourceNode)
 
 
 def input(filename, **kwargs):
@@ -32,6 +32,30 @@ def input(filename, **kwargs):
     return InputNode(input.__name__, kwargs=kwargs).stream()
 
 
+
+def source_multi_output(filter_name, *args, **kwargs):
+    """Apply custom filter with one or more outputs.
+
+    This is the same as ``filter_`` except that the filter can produce more than one output.
+
+    To reference an output stream, use either the ``.stream`` operator or bracket shorthand:
+
+    Example:
+
+        ```
+        split = ffmpeg.input('in.mp4').filter_multi_output('split')
+        split0 = split.stream(0)
+        split1 = split[1]
+        ffmpeg.concat(split0, split1).output('out.mp4').run()
+        ```
+    """
+    return SourceNode(filter_name, args=args, kwargs=kwargs)
+
+
+def source(filter_name, *args, **kwargs):
+    return source_multi_output(filter_name, *args, **kwargs).stream()
+
+
 @output_operator()
 def global_args(stream, *args):
     """Add extra global command-line argument(s), e.g. ``-progress``.
@@ -94,4 +118,11 @@ def output(*streams_and_filename, **kwargs):
     return OutputNode(streams, output.__name__, kwargs=kwargs).stream()
 
 
-__all__ = ['input', 'merge_outputs', 'output', 'overwrite_output']
+__all__ = [
+    'input',
+    'source_multi_output',
+    'source',
+    'merge_outputs',
+    'output',
+    'overwrite_output',
+]
diff --git a/ffmpeg/_run.py b/ffmpeg/_run.py
index c9cbb7c..10e203f 100644
--- a/ffmpeg/_run.py
+++ b/ffmpeg/_run.py
@@ -16,7 +16,7 @@ from .nodes import (
     InputNode,
     OutputNode,
     output_operator,
-)
+    SourceNode)
 
 
 class Error(Exception):
@@ -156,10 +156,11 @@ def get_args(stream_spec, overwrite_output=False):
     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)]
+    filter_nodes = [node for node in sorted_nodes if isinstance(node, (FilterNode, SourceNode))]
     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_input_args(node) for node in input_nodes])
+    if len(input_nodes) > 0:
+        args += reduce(operator.add, [_get_input_args(node) for node in input_nodes])
     if filter_arg:
         args += ['-filter_complex', filter_arg]
     args += reduce(
diff --git a/ffmpeg/nodes.py b/ffmpeg/nodes.py
index cacab8e..aa86be9 100644
--- a/ffmpeg/nodes.py
+++ b/ffmpeg/nodes.py
@@ -234,9 +234,7 @@ 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
-        )
+        super(FilterableStream, self).__init__(upstream_node, upstream_label, {InputNode, FilterNode, SourceNode}, upstream_selector)
 
 
 # noinspection PyMethodOverriding
@@ -261,20 +259,8 @@ class InputNode(Node):
 
 
 # noinspection PyMethodOverriding
-class FilterNode(Node):
-    def __init__(self, stream_spec, name, max_inputs=1, args=[], kwargs={}):
-        super(FilterNode, self).__init__(
-            stream_spec=stream_spec,
-            name=name,
-            incoming_stream_types={FilterableStream},
-            outgoing_stream_type=FilterableStream,
-            min_inputs=1,
-            max_inputs=max_inputs,
-            args=args,
-            kwargs=kwargs,
-        )
-
-    """FilterNode"""
+class FilterableNode(Node):
+    """FilterableNode"""
 
     def _get_filter(self, outgoing_edges):
         args = self.args
@@ -300,6 +286,37 @@ class FilterNode(Node):
         return escape_chars(params_text, '\\\'[],;')
 
 
+# noinspection PyMethodOverriding
+class FilterNode(FilterableNode):
+    """FilterNode"""
+    def __init__(self, stream_spec, name, max_inputs=1, args=[], kwargs={}):
+        super(FilterNode, self).__init__(
+            stream_spec=stream_spec,
+            name=name,
+            incoming_stream_types={FilterableStream},
+            outgoing_stream_type=FilterableStream,
+            min_inputs=1,
+            max_inputs=max_inputs,
+            args=args,
+            kwargs=kwargs,
+        )
+
+
+# noinspection PyMethodOverriding
+class SourceNode(FilterableNode):
+    def __init__(self, name, args=[], kwargs={}):
+        super(SourceNode, 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 OutputNode(Node):
     def __init__(self, stream, name, args=[], kwargs={}):