#!/usr/bin/env python import distutils.spawn import re import subprocess class ShellCommand(object): """A shell command. _executable contains the full path to the relevant executable. _base_options is a list of standard general options for this command. """ _executable = "" _base_options = [] def __init__(self, options=[]): self.options = options def __repr__(self): return "<{cls}: {cmd}>".format( cls=self.__class__.__name__, cmd=" ".join(self.command_items(True))) def command_items(self, debug=False): """Return the list of items representing the command.""" return ([self._executable] + self._base_options + self.options) def run(self): """Execute the command in a subprocess.""" return subprocess.call(self.command_items()) def get_output(self): """Execute the command in a subprocess and return the output.""" return subprocess.check_output(self.command_items()) class ConvertCommand(ShellCommand): """An ImageMagick convert command.""" _executable = distutils.spawn.find_executable("convert") _base_options = ["-scale", "2048x1536", "-density", "600", "-background", "white", "-flatten"] class FFprobeCommand(ShellCommand): """An ffprobe shell command.""" _executable = distutils.spawn.find_executable("ffprobe") _base_options = ["-loglevel", "error"] class FFmpegCommand(ShellCommand): """A "simple" ffmpeg shell command.""" _executable = distutils.spawn.find_executable("ffmpeg") _base_options = ["-y", "-loglevel", "error", "-nostdin"] def __init__(self, input_options=[], output_options=[]): self.input_options = input_options self.output_options = output_options def append_input_options(self, items=[]): """Add a list of items to the end of the input options.""" self.input_options += items def prepend_input_options(self, items=[]): """Add a list of items at the front of the input options.""" self.input_options = items + self.input_options def append_output_options(self, items=[]): """Add a list of items to the end of the output options.""" self.output_options += items def prepend_output_options(self, items=[]): """Add a list of items at the front of the output options.""" self.output_options = items + self.output_options def command_items(self, debug=False): """Return the list of items representing the command.""" return ([self._executable] + self._base_options + self.input_options + self.output_options) class FFmpegConcatCommand(FFmpegCommand): """An ffmpeg shell command with a complex concat filter.""" def __init__(self, input_options=[], output_options=[]): super(FFmpegConcatCommand, self).__init__( input_options, output_options) self.prepend_output_options(["-codec:a", "pcm_s16le", "-ac", "1", "-codec:v", "h264", "-pix_fmt", "yuv420p", "-map", "[vconc]", "-map", "[anorm]"]) self.filters = [] def append_filter(self, filter): """Append a filter to the filters list.""" self.filters.append(filter) def append_normalisation_filter(self): """Append a normalisation audio filter to the complex filter.""" self.append_filter("[aconc] dynaudnorm=r=0.25:f=10:b=y [anorm]") def append_concat_filter(self, type, segments=[]): """Append a concat filter to the filters list""" if (len(segments) > 1): self.append_filter( "{inspecs} concat=n={n}:v={v}:a={a} [{t}conc]".format( inspecs=" ".join([s.output_stream_specifier() for s in segments]), n=len(segments), v=int(type == "v"), a=int(type == "a"), t=type)) elif (len(segments) == 1): self.append_filter( "{inspec} {a}null [{t}conc]".format( inspec=segments[0].output_stream_specifier(), a=type if type == "a" else "", t=type)) def build_complex_filter(self): """Build the complete complex filter. Filters in the filtergraph are separated by ";". """ return "{f}".format(f=";".join(self.filters)) def command_items(self, debug=False): """Return the list of items representing the command.""" complex_filter = self.build_complex_filter() output_opts = self.output_options if (debug): # Wrap the output streams and the entire complex filter # in 'single quotes', so that we can copy and paste the # command string directly into the shell for testing. complex_filter = "'{f}'".format(f=complex_filter) output_opts = [re.sub(r"\[(\w+)\]", r"'[\1]'", s) for s in self.output_options] return ([self._executable] + self._base_options + self.input_options + ["-filter_complex", complex_filter] + output_opts) if (__name__ == "__main__"): print ShellCommand() print ConvertCommand(options=["in.pdf"]) print FFprobeCommand(options=["-i", "in.mov"]) print FFmpegCommand(input_options=["-i", "in.mov"], output_options=["out.mov"]) concat = FFmpegConcatCommand(input_options=["-i", "in.mov"], output_options=["out.mov"]) concat.append_normalisation_filter() print concat