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  • @chapter Syntax
    @c man begin SYNTAX
    
    When evaluating specific formats, FFmpeg uses internal library parsing
    functions, shared by the tools. This section documents the syntax of
    some of these formats.
    
    @anchor{date syntax}
    @section Date
    
    The accepted syntax is:
    @example
    [(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH:MM:SS[.m...]]])|(HHMMSS[.m...]]]))[Z]
    now
    @end example
    
    If the value is "now" it takes the current time.
    
    Time is local time unless Z is appended, in which case it is
    interpreted as UTC.
    If the year-month-day part is not specified it takes the current
    year-month-day.
    
    @anchor{time duration syntax}
    @section Time duration
    
    The accepted syntax is:
    @example
    [-]HH:MM:SS[.m...]
    [-]S+[.m...]
    @end example
    
    @var{HH} expresses the number of hours, @var{MM} the number a of minutes
    and @var{SS} the number of seconds.
    
    @anchor{video size syntax}
    @section Video size
    Specify the size of the sourced video, it may be a string of the form
    @var{width}x@var{height}, or the name of a size abbreviation.
    
    The following abbreviations are recognized:
    @table @samp
    @item sqcif
    128x96
    @item qcif
    176x144
    @item cif
    352x288
    @item 4cif
    704x576
    @item 16cif
    1408x1152
    @item qqvga
    160x120
    @item qvga
    320x240
    @item vga
    640x480
    @item svga
    800x600
    @item xga
    1024x768
    @item uxga
    1600x1200
    @item qxga
    2048x1536
    @item sxga
    1280x1024
    @item qsxga
    2560x2048
    @item hsxga
    5120x4096
    @item wvga
    852x480
    @item wxga
    1366x768
    @item wsxga
    1600x1024
    @item wuxga
    1920x1200
    @item woxga
    2560x1600
    @item wqsxga
    3200x2048
    @item wquxga
    3840x2400
    @item whsxga
    6400x4096
    @item whuxga
    7680x4800
    @item cga
    320x200
    @item ega
    640x350
    @item hd480
    852x480
    @item hd720
    1280x720
    @item hd1080
    1920x1080
    @end table
    
    @anchor{video rate syntax}
    @section Video rate
    
    Specify the frame rate of a video, expressed as the number of frames
    generated per second. It has to be a string in the format
    @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
    number or a valid video frame rate abbreviation.
    
    The following abbreviations are recognized:
    @table @samp
    @item ntsc
    30000/1001
    @item pal
    25/1
    @item qntsc
    30000/1
    @item qpal
    25/1
    @item sntsc
    30000/1
    @item spal
    25/1
    @item film
    24/1
    @item ntsc-film
    24000/1
    @end table
    
    @anchor{ratio syntax}
    @section Ratio
    
    A ratio can be expressed as an expression, or in the form
    @var{numerator}:@var{denominator}.
    
    Note that a ratio with infinite (1/0) or negative value is
    considered valid, so you should check on the returned value if you
    want to exclude those values.
    
    The undefined value can be expressed using the "0:0" string.
    
    @anchor{color syntax}
    @section Color
    
    It can be the name of a color (case insensitive match) or a
    
    [0x|#]RRGGBB[AA] sequence, possibly followed by "@@" and a string
    
    representing the alpha component.
    
    The alpha component may be a string composed by "0x" followed by an
    hexadecimal number or a decimal number between 0.0 and 1.0, which
    represents the opacity value (0x00/0.0 means completely transparent,
    0xff/1.0 completely opaque).
    If the alpha component is not specified then 0xff is assumed.
    
    The string "random" will result in a random color.
    
    @c man end SYNTAX