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diff --git a/doc/syntax.texi b/doc/syntax.texi new file mode 100644 index 0000000000..f52e7638d2 --- /dev/null +++ b/doc/syntax.texi @@ -0,0 +1,158 @@ +@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 |