@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