commit ae89e7b095a4d6ad32cbff9f7183f8067154683a
Author: Karl Kroening <karlk@kralnet.us>
Date:   Sat May 13 18:27:06 2017 -1000

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..56d875b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+venv
+.cache
+tests/dummy2.mp4
diff --git a/ffmpeg.py b/ffmpeg.py
new file mode 100755
index 0000000..5b9903b
--- /dev/null
+++ b/ffmpeg.py
@@ -0,0 +1,252 @@
+#!./venv/bin/python
+
+from functools import partial
+import hashlib
+import json
+import operator
+import subprocess
+
+
+def _create_root_node(node_class, *args, **kwargs):
+    root = node_class(*args, **kwargs)
+    root._update_hash()
+    return root
+
+
+def _create_child_node(node_class, parent, *args, **kwargs):
+    child = node_class([parent], *args, **kwargs)
+    child._update_hash()
+    return child
+
+
+class _Node(object):
+    def __init__(self, parents):
+        parent_hashes = [parent.hash for parent in parents]
+        assert len(parent_hashes) == len(set(parent_hashes)), 'Same node cannot be included as parent multiple times'
+        self.parents = parents
+
+    @classmethod
+    def _add_operator(cls, node_class):
+        if getattr(node_class, 'STATIC', False):
+            @classmethod
+            def func(cls2, *args, **kwargs):
+                return _create_root_node(node_class, *args, **kwargs)
+        else:
+            def func(self, *args, **kwargs):
+                return _create_child_node(node_class, self, *args, **kwargs)
+        setattr(cls, node_class.NAME, func)
+
+    @classmethod
+    def _add_operators(cls, node_classes):
+        [cls._add_operator(node_class) for node_class in node_classes]
+
+    @property
+    def _props(self):
+        return {k: v for k, v in self.__dict__.items() if k not in ['parents', 'hash']}
+
+    def __repr__(self):
+        # TODO: exclude default values.
+        props = self._props
+        formatted_props = ['{}={!r}'.format(key, props[key]) for key in sorted(self._props)]
+        return '{}({})'.format(self.NAME, ','.join(formatted_props))
+
+    def __eq__(self, other):
+        return self.hash == other.hash
+
+    def _update_hash(self):
+        my_hash = hashlib.md5(json.dumps(self._props)).hexdigest()
+        parent_hashes = [parent.hash for parent in self.parents]
+        hashes = parent_hashes + [my_hash]
+        self.hash = hashlib.md5(','.join(hashes)).hexdigest()
+
+
+class _InputNode(_Node):
+    pass
+
+
+class _FileInputNode(_InputNode):
+    NAME = 'file_input'
+    STATIC = True
+
+    def __init__(self, filename):
+        super(_FileInputNode, self).__init__(parents=[])
+        self.filename = filename
+
+
+class _FilterNode(_Node):
+    pass
+
+
+class _TrimFilterNode(_FilterNode):
+    NAME = 'trim'
+
+    def __init__(self, parents, start_frame, end_frame, setpts='PTS-STARTPTS'):
+        super(_TrimFilterNode, self).__init__(parents)
+        self.start_frame = start_frame
+        self.end_frame = end_frame
+        self.setpts = setpts
+
+
+class _ConcatNode(_Node):
+    NAME = 'concat'
+    STATIC = True
+
+    def __init__(self, *parents):
+        super(_ConcatNode, self).__init__(parents)
+
+
+class _OutputNode(_Node):
+    @classmethod
+    def _get_stream_name(cls, name):
+        return '[{}]'.format(name)
+
+    @classmethod
+    def _get_input_args(cls, input_node):
+        if isinstance(input_node, _FileInputNode):
+            args = ['-i', input_node.filename]
+        else:
+            assert False, 'Unsupported input node: {}'.format(input_node)
+        return args
+
+    @classmethod
+    def _topo_sort(cls, start_node):
+        marked_nodes = []
+        sorted_nodes = []
+        child_map = {}
+        def visit(node, child):
+            assert node not in marked_nodes, 'Graph is not a DAG'
+            if child is not None:
+                if node not in child_map:
+                    child_map[node] = []
+                child_map[node].append(child)
+            if node not in sorted_nodes:
+                marked_nodes.append(node)
+                [visit(parent, node) for parent in node.parents]
+                marked_nodes.remove(node)
+                sorted_nodes.append(node)
+        unmarked_nodes = [start_node]
+        while unmarked_nodes:
+            visit(unmarked_nodes.pop(), None)
+        return sorted_nodes, child_map
+
+    @classmethod
+    def _get_filter(cls, node):
+        # TODO: find a better way to do this instead of ugly if/elifs.
+        if isinstance(node, _TrimFilterNode):
+            return 'trim=start_frame={}:end_frame={},setpts={}'.format(node.start_frame, node.end_frame, node.setpts)
+        elif isinstance(node, _ConcatNode):
+            return 'concat=n={}'.format(len(node.parents))
+        else:
+            assert False, 'Unsupported filter node: {}'.format(node)
+
+    @classmethod
+    def _get_filter_spec(cls, i, node, stream_name_map):
+        stream_name = cls._get_stream_name('v{}'.format(i))
+        stream_name_map[node] = stream_name
+        inputs = [stream_name_map[parent] for parent in node.parents]
+        filter_spec = '{}{}{}'.format(''.join(inputs), cls._get_filter(node), stream_name)
+        return filter_spec
+
+    @classmethod
+    def _get_filter_arg(cls, filter_nodes, stream_name_map):
+        filter_specs = [cls._get_filter_spec(i, node, stream_name_map) for i, node in enumerate(filter_nodes)]
+        return ';'.join(filter_specs)
+
+    @classmethod
+    def _get_global_args(cls, node):
+        if isinstance(node, _OverwriteOutputNode):
+            return ['-y']
+        else:
+            assert False, 'Unsupported global node: {}'.format(node)
+
+    @classmethod
+    def _get_output_args(cls, node, stream_name_map):
+        args = []
+        if not isinstance(node, _MergeOutputsNode):
+            stream_name = stream_name_map[node.parents[0]]
+            if stream_name != '[0]':
+                args += ['-map', stream_name]
+            if isinstance(node, _FileOutputNode):
+                args += [node.filename]
+            else:
+                assert False, 'Unsupported output node: {}'.format(node)
+        return args
+
+    def get_args(self):
+        args = []
+        # TODO: group nodes together, e.g. `-i somefile -r somerate`.
+        sorted_nodes, child_map = self._topo_sort(self)
+        input_nodes = [node for node in sorted_nodes if isinstance(node, _InputNode)]
+        output_nodes = [node for node in sorted_nodes if isinstance(node, _OutputNode) and not
+            isinstance(node, _GlobalNode)]
+        global_nodes = [node for node in sorted_nodes if isinstance(node, _GlobalNode)]
+        filter_nodes = [node for node in sorted_nodes if node not in (input_nodes + output_nodes + global_nodes)]
+        stream_name_map = {node: self._get_stream_name(i) for i, node in enumerate(input_nodes)}
+        filter_arg = self._get_filter_arg(filter_nodes, stream_name_map)
+        args += reduce(operator.add, [self._get_input_args(node) for node in input_nodes])
+        if filter_arg:
+            args += ['-filter_complex', filter_arg]
+        args += reduce(operator.add, [self._get_output_args(node, stream_name_map) for node in output_nodes])
+        args += reduce(operator.add, [self._get_global_args(node) for node in global_nodes], [])
+        return args
+
+    def run(self):
+        args = ['ffmpeg'] + self.get_args()
+        subprocess.check_call(args)
+
+
+class _GlobalNode(_OutputNode):
+    def __init__(self, parents):
+        assert len(parents) == 1
+        assert isinstance(parents[0], _OutputNode), 'Global nodes can only be attached after output nodes'
+        super(_GlobalNode, self).__init__(parents)
+
+
+class _OverwriteOutputNode(_GlobalNode):
+    NAME = 'overwrite_output'
+
+
+
+class _MergeOutputsNode(_OutputNode):
+    NAME = 'merge_outputs'
+
+    def __init__(self, *parents):
+        assert not any([not isinstance(parent, _OutputNode) for parent in parents]), 'Can only merge output streams'
+        super(_MergeOutputsNode, self).__init__(*parents)
+
+
+class _FileOutputNode(_OutputNode):
+    NAME = 'file_output'
+
+    def __init__(self, parents, filename):
+        super(_FileOutputNode, self).__init__(parents)
+        self.filename = filename
+
+
+NODE_CLASSES = [
+    _ConcatNode,
+    _FileInputNode,
+    _FileOutputNode,
+    _OverwriteOutputNode,
+    _TrimFilterNode,
+]
+
+_Node._add_operators(NODE_CLASSES)
+
+
+for node_class in NODE_CLASSES:
+    if getattr(node_class, 'STATIC', False):
+        func = _create_root_node
+    else:
+        func = _create_child_node
+    globals()[node_class.NAME] = partial(func, node_class)
+
+
+def get_args(node):
+    assert isinstance(node, _OutputNode), 'Cannot generate ffmpeg args for non-output node'
+    return node.get_args()
+
+
+def run(node):
+    assert isinstance(node, _OutputNode), 'Cannot run ffmpeg on non-output node'
+    return node.run()
diff --git a/pytest.ini b/pytest.ini
new file mode 100644
index 0000000..2423407
--- /dev/null
+++ b/pytest.ini
@@ -0,0 +1,3 @@
+[pytest]
+testpaths = tests
+#norecursedirs = venv .git
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..e079f8a
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1 @@
+pytest
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/dummy.mp4 b/tests/dummy.mp4
new file mode 100644
index 0000000..2c7d59e
Binary files /dev/null and b/tests/dummy.mp4 differ
diff --git a/tests/test_ffmpeg.py b/tests/test_ffmpeg.py
new file mode 100644
index 0000000..9a8ef95
--- /dev/null
+++ b/tests/test_ffmpeg.py
@@ -0,0 +1,104 @@
+import ffmpeg
+import os
+
+
+TEST_DIR = os.path.dirname(__file__)
+TEST_INPUT_FILE = os.path.join(TEST_DIR, 'dummy.mp4')
+TEST_OUTPUT_FILE = os.path.join(TEST_DIR, 'dummy2.mp4')
+
+
+def test_fluent_equality():
+    base1 = ffmpeg.file_input('dummy1.mp4')
+    base2 = ffmpeg.file_input('dummy1.mp4')
+    base3 = ffmpeg.file_input('dummy2.mp4')
+    t1 = base1.trim(10, 20)
+    t2 = base1.trim(10, 20)
+    t3 = base1.trim(10, 30)
+    t4 = base2.trim(10, 20)
+    t5 = base3.trim(10, 20)
+    assert t1 == t2
+    assert t1 != t3
+    assert t1 == t4
+    assert t1 != t5
+
+
+def test_fluent_concat():
+    base = ffmpeg.file_input('dummy.mp4')
+    trimmed1 = base.trim(10, 20)
+    trimmed2 = base.trim(30, 40)
+    trimmed3 = base.trim(50, 60)
+    concat1 = ffmpeg.concat(trimmed1, trimmed2, trimmed3)
+    concat2 = ffmpeg.concat(trimmed1, trimmed2, trimmed3)
+    concat3 = ffmpeg.concat(trimmed1, trimmed3, trimmed2)
+    concat4 = ffmpeg.concat()
+    concat5 = ffmpeg.concat()
+    assert concat1 == concat2
+    assert concat1 != concat3
+    assert concat4 == concat5
+
+
+def test_fluent_output():
+    ffmpeg \
+        .file_input('dummy.mp4') \
+        .trim(10, 20) \
+        .file_output('dummy2.mp4')
+
+
+def test_fluent_complex_filter():
+    in_file = ffmpeg.file_input('dummy.mp4')
+    return ffmpeg \
+        .concat(
+            in_file.trim(10, 20),
+            in_file.trim(30, 40),
+            in_file.trim(50, 60)
+        ) \
+        .file_output('dummy2.mp4')
+
+
+def test_repr():
+    in_file = ffmpeg.file_input('dummy.mp4')
+    trim1 = ffmpeg.trim(in_file, 10, 20)
+    trim2 = ffmpeg.trim(in_file, 30, 40)
+    trim3 = ffmpeg.trim(in_file, 50, 60)
+    concatted = ffmpeg.concat(trim1, trim2, trim3)
+    output = ffmpeg.file_output(concatted, 'dummy2.mp4')
+    assert repr(in_file) == "file_input(filename='dummy.mp4')"
+    assert repr(trim1) == "trim(end_frame=20,setpts='PTS-STARTPTS',start_frame=10)"
+    assert repr(trim2) == "trim(end_frame=40,setpts='PTS-STARTPTS',start_frame=30)"
+    assert repr(trim3) == "trim(end_frame=60,setpts='PTS-STARTPTS',start_frame=50)"
+    assert repr(concatted) == "concat()"
+    assert repr(output) == "file_output(filename='dummy2.mp4')"
+
+
+def test_get_args_simple():
+    out_file = ffmpeg.file_input('dummy.mp4').file_output('dummy2.mp4')
+    assert out_file.get_args() == ['-i', 'dummy.mp4', 'dummy2.mp4']
+
+
+def _get_complex_filter_example():
+    in_file = ffmpeg.file_input(TEST_INPUT_FILE)
+    concatted = ffmpeg.concat(
+        ffmpeg.trim(in_file, 10, 20),
+        ffmpeg.trim(in_file, 30, 40),
+        ffmpeg.trim(in_file, 50, 60),
+    )
+    out = ffmpeg.file_output(concatted, TEST_OUTPUT_FILE)
+    return ffmpeg.overwrite_output(out)
+
+
+def test_get_args_complex_filter():
+    out = _get_complex_filter_example()
+    assert ffmpeg.get_args(out) == [
+        '-i', TEST_INPUT_FILE,
+        '-filter_complex', 
+            '[0]trim=start_frame=10:end_frame=20,setpts=PTS-STARTPTS[v0];' \
+            '[0]trim=start_frame=30:end_frame=40,setpts=PTS-STARTPTS[v1];' \
+            '[0]trim=start_frame=50:end_frame=60,setpts=PTS-STARTPTS[v2];' \
+            '[v0][v1][v2]concat=n=3[v3]',
+        '-map', '[v3]', TEST_OUTPUT_FILE,
+        '-y',
+    ]
+
+
+def test_run():
+    ffmpeg.run(_get_complex_filter_example())