ffmpeg\_filters.py

from __future__ import unicode_literals

from .nodes import FilterNode, filter_operator
from ._utils import escape_chars


@filter_operator()
def filter_multi_output(stream_spec, 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 FilterNode(
        stream_spec, filter_name, args=args, kwargs=kwargs, max_inputs=None
    )


@filter_operator()
def filter(stream_spec, filter_name, *args, **kwargs):
    """Apply custom filter.

    ``filter_`` is normally used by higher-level filter functions such as ``hflip``, but if a filter implementation
    is missing from ``ffmpeg-python``, you can call ``filter_`` directly to have ``ffmpeg-python`` pass the filter name
    and arguments to ffmpeg verbatim.

    Args:
        stream_spec: a Stream, list of Streams, or label-to-Stream dictionary mapping
        filter_name: ffmpeg filter name, e.g. `colorchannelmixer`
        *args: list of args to pass to ffmpeg verbatim
        **kwargs: list of keyword-args to pass to ffmpeg verbatim

    The function name is suffixed with ``_`` in order avoid confusion with the standard python ``filter`` function.

    Example:

        ``ffmpeg.input('in.mp4').filter('hflip').output('out.mp4').run()``
    """
    return filter_multi_output(stream_spec, filter_name, *args, **kwargs).stream()


@filter_operator()
def filter_(stream_spec, filter_name, *args, **kwargs):
    """Alternate name for ``filter``, so as to not collide with the
    built-in python ``filter`` operator.
    """
    return filter(stream_spec, filter_name, *args, **kwargs)


@filter_operator()
def split(stream):
    return FilterNode(stream, split.__name__)


@filter_operator()
def asplit(stream):
    return FilterNode(stream, asplit.__name__)


@filter_operator()
def setpts(stream, expr):
    """Change the PTS (presentation timestamp) of the input frames.

    Args:
        expr: The expression which is evaluated for each frame to construct its timestamp.

    Official documentation: `setpts, asetpts <https://ffmpeg.org/ffmpeg-filters.html#setpts_002c-asetpts>`__
    """
    return FilterNode(stream, setpts.__name__, args=[expr]).stream()


@filter_operator()
def trim(stream, **kwargs):
    """Trim the input so that the output contains one continuous subpart of the input.

    Args:
        start: Specify the time of the start of the kept section, i.e. the frame with the timestamp start will be the
            first frame in the output.
        end: Specify the time of the first frame that will be dropped, i.e. the frame immediately preceding the one
            with the timestamp end will be the last frame in the output.
        start_pts: This is the same as start, except this option sets the start timestamp in timebase units instead of
            seconds.
        end_pts: This is the same as end, except this option sets the end timestamp in timebase units instead of
            seconds.
        duration: The maximum duration of the output in seconds.
        start_frame: The number of the first frame that should be passed to the output.
        end_frame: The number of the first frame that should be dropped.

    Official documentation: `trim <https://ffmpeg.org/ffmpeg-filters.html#trim>`__
    """
    return FilterNode(stream, trim.__name__, kwargs=kwargs).stream()


@filter_operator()
def overlay(main_parent_node, overlay_parent_node, eof_action='repeat', **kwargs):
    """Overlay one video on top of another.

    Args:
        x: Set the expression for the x coordinates of the overlaid video on the main video. Default value is 0. In
            case the expression is invalid, it is set to a huge value (meaning that the overlay will not be displayed
            within the output visible area).
        y: Set the expression for the y coordinates of the overlaid video on the main video. Default value is 0. In
            case the expression is invalid, it is set to a huge value (meaning that the overlay will not be displayed
            within the output visible area).
        eof_action: The action to take when EOF is encountered on the secondary input; it accepts one of the following
            values:

            * ``repeat``: Repeat the last frame (the default).
            * ``endall``: End both streams.
            * ``pass``: Pass the main input through.

        eval: Set when the expressions for x, and y are evaluated.
            It accepts the following values:

            * ``init``: only evaluate expressions once during the filter initialization or when a command is
                processed
            * ``frame``: evaluate expressions for each incoming frame

            Default value is ``frame``.
        shortest: If set to 1, force the output to terminate when the shortest input terminates. Default value is 0.
        format: Set the format for the output video.
            It accepts the following values:

            * ``yuv420``: force YUV420 output
            * ``yuv422``: force YUV422 output
            * ``yuv444``: force YUV444 output
            * ``rgb``: force packed RGB output
            * ``gbrp``: force planar RGB output

            Default value is ``yuv420``.
        rgb (deprecated): If set to 1, force the filter to accept inputs in the RGB color space. Default value is 0.
            This option is deprecated, use format instead.
        repeatlast: If set to 1, force the filter to draw the last overlay frame over the main input until the end of
            the stream. A value of 0 disables this behavior. Default value is 1.

    Official documentation: `overlay <https://ffmpeg.org/ffmpeg-filters.html#overlay-1>`__
    """
    kwargs['eof_action'] = eof_action
    return FilterNode(
        [main_parent_node, overlay_parent_node],
        overlay.__name__,
        kwargs=kwargs,
        max_inputs=2,
    ).stream()


@filter_operator()
def hflip(stream):
    """Flip the input video horizontally.

    Official documentation: `hflip <https://ffmpeg.org/ffmpeg-filters.html#hflip>`__
    """
    return FilterNode(stream, hflip.__name__).stream()


@filter_operator()
def vflip(stream):
    """Flip the input video vertically.

    Official documentation: `vflip <https://ffmpeg.org/ffmpeg-filters.html#vflip>`__
    """
    return FilterNode(stream, vflip.__name__).stream()


@filter_operator()
def crop(stream, x, y, width, height, **kwargs):
    """Crop the input video.

    Args:
        x: The horizontal position, in the input video, of the left edge of
           the output video.
        y: The vertical position, in the input video, of the top edge of the
           output video.
        width: The width of the output video. Must be greater than 0.
        heigth: The height of the output video. Must be greater than 0.

    Official documentation: `crop <https://ffmpeg.org/ffmpeg-filters.html#crop>`__
    """
    return FilterNode(
        stream, crop.__name__, args=[width, height, x, y], kwargs=kwargs
    ).stream()


@filter_operator()
def drawbox(stream, x, y, width, height, color, thickness=None, **kwargs):
    """Draw a colored box on the input image.

    Args:
        x: The expression which specifies the top left corner x coordinate of the box. It defaults to 0.
        y: The expression which specifies the top left corner y coordinate of the box. It defaults to 0.
        width: Specify the width of the box; if 0 interpreted as the input width. It defaults to 0.
        heigth: Specify the height of the box; if 0 interpreted as the input height. It defaults to 0.
        color: Specify the color of the box to write. For the general syntax of this option, check the "Color" section
            in the ffmpeg-utils manual. If the special value invert is used, the box edge color is the same as the
            video with inverted luma.
        thickness: The expression which sets the thickness of the box edge. Default value is 3.
        w: Alias for ``width``.
        h: Alias for ``height``.
        c: Alias for ``color``.
        t: Alias for ``thickness``.

    Official documentation: `drawbox <https://ffmpeg.org/ffmpeg-filters.html#drawbox>`__
    """
    if thickness:
        kwargs['t'] = thickness
    return FilterNode(
        stream, drawbox.__name__, args=[x, y, width, height, color], kwargs=kwargs
    ).stream()


@filter_operator()
def drawtext(stream, text=None, x=0, y=0, escape_text=True, **kwargs):
    """Draw a text string or text from a specified file on top of a video, using the libfreetype library.

    To enable compilation of this filter, you need to configure FFmpeg with ``--enable-libfreetype``. To enable default
    font fallback and the font option you need to configure FFmpeg with ``--enable-libfontconfig``. To enable the
    text_shaping option, you need to configure FFmpeg with ``--enable-libfribidi``.

    Args:
        box: Used to draw a box around text using the background color. The value must be either 1 (enable) or 0
            (disable). The default value of box is 0.
        boxborderw: Set the width of the border to be drawn around the box using boxcolor. The default value of
            boxborderw is 0.
        boxcolor: The color to be used for drawing box around text. For the syntax of this option, check the "Color"
            section in the ffmpeg-utils manual.  The default value of boxcolor is "white".
        line_spacing: Set the line spacing in pixels of the border to be drawn around the box using box. The default
            value of line_spacing is 0.
        borderw: Set the width of the border to be drawn around the text using bordercolor. The default value of
            borderw is 0.
        bordercolor: Set the color to be used for drawing border around text. For the syntax of this option, check the
            "Color" section in the ffmpeg-utils manual.  The default value of bordercolor is "black".
        expansion: Select how the text is expanded. Can be either none, strftime (deprecated) or normal (default). See
            the Text expansion section below for details.
        basetime: Set a start time for the count. Value is in microseconds. Only applied in the deprecated strftime
            expansion mode. To emulate in normal expansion mode use the pts function, supplying the start time (in
            seconds) as the second argument.
        fix_bounds: If true, check and fix text coords to avoid clipping.
        fontcolor: The color to be used for drawing fonts. For the syntax of this option, check the "Color" section in
            the ffmpeg-utils manual.  The default value of fontcolor is "black".
        fontcolor_expr: String which is expanded the same way as text to obtain dynamic fontcolor value. By default
            this option has empty value and is not processed. When this option is set, it overrides fontcolor option.
        font: The font family to be used for drawing text. By default Sans.
        fontfile: The font file to be used for drawing text. The path must be included. This parameter is mandatory if
            the fontconfig support is disabled.
        alpha: Draw the text applying alpha blending. The value can be a number between 0.0 and 1.0. The expression
            accepts the same variables x, y as well. The default value is 1. Please see fontcolor_expr.
        fontsize: The font size to be used for drawing text. The default value of fontsize is 16.
        text_shaping: If set to 1, attempt to shape the text (for example, reverse the order of right-to-left text and
            join Arabic characters) before drawing it. Otherwise, just draw the text exactly as given. By default 1 (if
            supported).
        ft_load_flags: The flags to be used for loading the fonts. The flags map the corresponding flags supported by
            libfreetype, and are a combination of the following values:

            * ``default``
            * ``no_scale``
            * ``no_hinting``
            * ``render``
            * ``no_bitmap``
            * ``vertical_layout``
            * ``force_autohint``
            * ``crop_bitmap``
            * ``pedantic``
            * ``ignore_global_advance_width``
            * ``no_recurse``
            * ``ignore_transform``
            * ``monochrome``
            * ``linear_design``
            * ``no_autohint``

            Default value is "default".  For more information consult the documentation for the FT_LOAD_* libfreetype
            flags.
        shadowcolor: The color to be used for drawing a shadow behind the drawn text. For the syntax of this option,
            check the "Color" section in the ffmpeg-utils manual.  The default value of shadowcolor is "black".
        shadowx: The x offset for the text shadow position with respect to the position of the text. It can be either
            positive or negative values. The default value is "0".
        shadowy: The y offset for the text shadow position with respect to the position of the text. It can be either
            positive or negative values. The default value is "0".
        start_number: The starting frame number for the n/frame_num variable. The default value is "0".
        tabsize: The size in number of spaces to use for rendering the tab. Default value is 4.
        timecode: Set the initial timecode representation in "hh:mm:ss[:;.]ff" format. It can be used with or without
            text parameter. timecode_rate option must be specified.
        rate: Set the timecode frame rate (timecode only).
        timecode_rate: Alias for ``rate``.
        r: Alias for ``rate``.
        tc24hmax: If set to 1, the output of the timecode option will wrap around at 24 hours. Default is 0 (disabled).
        text: The text string to be drawn. The text must be a sequence of UTF-8 encoded characters. This parameter is
            mandatory if no file is specified with the parameter textfile.
        textfile: A text file containing text to be drawn. The text must be a sequence of UTF-8 encoded characters.
            This parameter is mandatory if no text string is specified with the parameter text.  If both text and
            textfile are specified, an error is thrown.
        reload: If set to 1, the textfile will be reloaded before each frame. Be sure to update it atomically, or it
            may be read partially, or even fail.
        x: The expression which specifies the offset where text will be drawn within the video frame. It is relative to
            the left border of the output image. The default value is "0".
        y: The expression which specifies the offset where text will be drawn within the video frame. It is relative to
            the top border of the output image. The default value is "0".  See below for the list of accepted constants
            and functions.

    Expression constants:
        The parameters for x and y are expressions containing the following constants and functions:
         - dar: input display aspect ratio, it is the same as ``(w / h) * sar``
         - hsub: horizontal chroma subsample values. For example for the pixel format "yuv422p" hsub is 2 and vsub
           is 1.
         - vsub: vertical chroma subsample values. For example for the pixel format "yuv422p" hsub is 2 and vsub
           is 1.
         - line_h: the height of each text line
         - lh: Alias for ``line_h``.
         - main_h: the input height
         - h: Alias for ``main_h``.
         - H: Alias for ``main_h``.
         - main_w: the input width
         - w: Alias for ``main_w``.
         - W: Alias for ``main_w``.
         - ascent: the maximum distance from the baseline to the highest/upper grid coordinate used to place a glyph
           outline point, for all the rendered glyphs. It is a positive value, due to the grid's orientation with the Y
           axis upwards.
         - max_glyph_a: Alias for ``ascent``.
         - descent: the maximum distance from the baseline to the lowest grid coordinate used to place a glyph outline
           point, for all the rendered glyphs. This is a negative value, due to the grid's orientation, with the Y axis
           upwards.
         - max_glyph_d: Alias for ``descent``.
         - max_glyph_h: maximum glyph height, that is the maximum height for all the glyphs contained in the rendered
           text, it is equivalent to ascent - descent.
         - max_glyph_w: maximum glyph width, that is the maximum width for all the glyphs contained in the rendered
           text.
         - n: the number of input frame, starting from 0
         - rand(min, max): return a random number included between min and max
         - sar: The input sample aspect ratio.
         - t: timestamp expressed in seconds, NAN if the input timestamp is unknown
         - text_h: the height of the rendered text
         - th: Alias for ``text_h``.
         - text_w: the width of the rendered text
         - tw: Alias for ``text_w``.
         - x: the x offset coordinates where the text is drawn.
         - y: the y offset coordinates where the text is drawn.

        These parameters allow the x and y expressions to refer each other, so you can for example specify
        ``y=x/dar``.

    Official documentation: `drawtext <https://ffmpeg.org/ffmpeg-filters.html#drawtext>`__
    """
    if text is not None:
        if escape_text:
            text = escape_chars(text, '\\\'%')
        kwargs['text'] = text
    if x != 0:
        kwargs['x'] = x
    if y != 0:
        kwargs['y'] = y
    return filter(stream, drawtext.__name__, **kwargs)


@filter_operator()
def concat(*streams, **kwargs):
    """Concatenate audio and video streams, joining them together one after the other.

    The filter works on segments of synchronized video and audio streams. All segments must have the same number of
    streams of each type, and that will also be the number of streams at output.

    Args:
        unsafe: Activate unsafe mode: do not fail if segments have a different format.

    Related streams do not always have exactly the same duration, for various reasons including codec frame size or
    sloppy authoring. For that reason, related synchronized streams (e.g. a video and its audio track) should be
    concatenated at once. The concat filter will use the duration of the longest stream in each segment (except the
    last one), and if necessary pad shorter audio streams with silence.

    For this filter to work correctly, all segments must start at timestamp 0.

    All corresponding streams must have the same parameters in all segments; the filtering system will automatically
    select a common pixel format for video streams, and a common sample format, sample rate and channel layout for
    audio streams, but other settings, such as resolution, must be converted explicitly by the user.

    Different frame rates are acceptable but will result in variable frame rate at output; be sure to configure the
    output file to handle it.

    Official documentation: `concat <https://ffmpeg.org/ffmpeg-filters.html#concat>`__
    """
    video_stream_count = kwargs.get('v', 1)
    audio_stream_count = kwargs.get('a', 0)
    stream_count = video_stream_count + audio_stream_count
    if len(streams) % stream_count != 0:
        raise ValueError(
            'Expected concat input streams to have length multiple of {} (v={}, a={}); got {}'.format(
                stream_count, video_stream_count, audio_stream_count, len(streams)
            )
        )
    kwargs['n'] = int(len(streams) / stream_count)
    return FilterNode(streams, concat.__name__, kwargs=kwargs, max_inputs=None).stream()


@filter_operator()
def zoompan(stream, **kwargs):
    """Apply Zoom & Pan effect.

    Args:
        zoom: Set the zoom expression. Default is 1.
        x: Set the x expression. Default is 0.
        y: Set the y expression. Default is 0.
        d: Set the duration expression in number of frames. This sets for how many number of frames effect will last
            for single input image.
        s: Set the output image size, default is ``hd720``.
        fps: Set the output frame rate, default is 25.
        z: Alias for ``zoom``.

    Official documentation: `zoompan <https://ffmpeg.org/ffmpeg-filters.html#zoompan>`__
    """
    return FilterNode(stream, zoompan.__name__, kwargs=kwargs).stream()


@filter_operator()
def hue(stream, **kwargs):
    """Modify the hue and/or the saturation of the input.

    Args:
        h: Specify the hue angle as a number of degrees. It accepts an expression, and defaults to "0".
        s: Specify the saturation in the [-10,10] range. It accepts an expression and defaults to "1".
        H: Specify the hue angle as a number of radians. It accepts an expression, and defaults to "0".
        b: Specify the brightness in the [-10,10] range. It accepts an expression and defaults to "0".

    Official documentation: `hue <https://ffmpeg.org/ffmpeg-filters.html#hue>`__
    """
    return FilterNode(stream, hue.__name__, kwargs=kwargs).stream()


@filter_operator()
def colorchannelmixer(stream, *args, **kwargs):
    """Adjust video input frames by re-mixing color channels.

    Official documentation: `colorchannelmixer <https://ffmpeg.org/ffmpeg-filters.html#colorchannelmixer>`__
    """
    return FilterNode(stream, colorchannelmixer.__name__, kwargs=kwargs).stream()


__all__ = [
    'colorchannelmixer',
    'concat',
    'crop',
    'drawbox',
    'drawtext',
    'filter',
    'filter_',
    'filter_multi_output',
    'hflip',
    'hue',
    'overlay',
    'setpts',
    'trim',
    'vflip',
    'zoompan',
]