_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.
        height: 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.
        height: 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',
]