mirror of
https://github.com/kkroening/ffmpeg-python.git
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120 lines
3.7 KiB
Python
120 lines
3.7 KiB
Python
import operator as _operator
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import subprocess as _subprocess
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from ._ffmpeg import (
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input,
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merge_outputs,
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output,
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overwrite_output,
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)
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from .nodes import (
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GlobalNode,
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InputNode,
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operator,
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OutputNode,
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)
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def _get_stream_name(name):
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return '[{}]'.format(name)
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def _get_input_args(input_node):
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if input_node._name == input.__name__:
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args = ['-i', input_node._kwargs['filename']]
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else:
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assert False, 'Unsupported input node: {}'.format(input_node)
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return args
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def _topo_sort(start_node):
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marked_nodes = []
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sorted_nodes = []
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child_map = {}
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def visit(node, child):
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assert node not in marked_nodes, 'Graph is not a DAG'
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if child is not None:
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if node not in child_map:
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child_map[node] = []
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child_map[node].append(child)
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if node not in sorted_nodes:
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marked_nodes.append(node)
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[visit(parent, node) for parent in node._parents]
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marked_nodes.remove(node)
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sorted_nodes.append(node)
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unmarked_nodes = [start_node]
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while unmarked_nodes:
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visit(unmarked_nodes.pop(), None)
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return sorted_nodes, child_map
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def _get_filter_spec(i, node, stream_name_map):
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stream_name = _get_stream_name('v{}'.format(i))
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stream_name_map[node] = stream_name
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inputs = [stream_name_map[parent] for parent in node._parents]
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filter_spec = '{}{}{}'.format(''.join(inputs), node._get_filter(), stream_name)
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return filter_spec
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def _get_filter_arg(filter_nodes, stream_name_map):
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filter_specs = [_get_filter_spec(i, node, stream_name_map) for i, node in enumerate(filter_nodes)]
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return ';'.join(filter_specs)
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def _get_global_args(node):
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if node._name == overwrite_output.__name__:
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return ['-y']
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else:
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assert False, 'Unsupported global node: {}'.format(node)
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def _get_output_args(node, stream_name_map):
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args = []
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if node._name != merge_outputs.__name__:
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stream_name = stream_name_map[node._parents[0]]
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if stream_name != '[0]':
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args += ['-map', stream_name]
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if node._name == output.__name__:
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args += [node._kwargs['filename']]
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else:
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assert False, 'Unsupported output node: {}'.format(node)
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return args
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@operator(node_classes={OutputNode, GlobalNode})
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def get_args(node):
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"""Get command-line arguments for ffmpeg."""
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args = []
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# TODO: group nodes together, e.g. `-i somefile -r somerate`.
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sorted_nodes, child_map = _topo_sort(node)
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del(node)
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input_nodes = [node for node in sorted_nodes if isinstance(node, InputNode)]
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output_nodes = [node for node in sorted_nodes if isinstance(node, OutputNode) and not
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isinstance(node, GlobalNode)]
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global_nodes = [node for node in sorted_nodes if isinstance(node, GlobalNode)]
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filter_nodes = [node for node in sorted_nodes if node not in (input_nodes + output_nodes + global_nodes)]
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stream_name_map = {node: _get_stream_name(i) for i, node in enumerate(input_nodes)}
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filter_arg = _get_filter_arg(filter_nodes, stream_name_map)
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args += reduce(_operator.add, [_get_input_args(node) for node in input_nodes])
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if filter_arg:
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args += ['-filter_complex', filter_arg]
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args += reduce(_operator.add, [_get_output_args(node, stream_name_map) for node in output_nodes])
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args += reduce(_operator.add, [_get_global_args(node) for node in global_nodes], [])
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return args
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@operator(node_classes={OutputNode, GlobalNode})
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def run(node, cmd='ffmpeg'):
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"""Run ffmpeg on node graph."""
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if isinstance(cmd, basestring):
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cmd = [cmd]
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elif type(cmd) != list:
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cmd = list(cmd)
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args = cmd + node.get_args()
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_subprocess.check_call(args)
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__all__ = [
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'get_args',
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'run',
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]
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