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Diffstat (limited to 'contrib/ffmpeg/doc/hooks.texi')
| -rw-r--r-- | contrib/ffmpeg/doc/hooks.texi | 45 |
1 files changed, 42 insertions, 3 deletions
diff --git a/contrib/ffmpeg/doc/hooks.texi b/contrib/ffmpeg/doc/hooks.texi index 49504509f..c410f1cb0 100644 --- a/contrib/ffmpeg/doc/hooks.texi +++ b/contrib/ffmpeg/doc/hooks.texi @@ -10,6 +10,12 @@ @chapter Introduction +@var{Please be aware that vhook is deprecated, and hence its development is +frozen (bug fixes are still accepted). +The substitute will be 'libavfilter', the result of our 'Video Filter API' +Google Summer of Code project. You may monitor its progress by subscribing to +the ffmpeg-soc mailing list at +@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-soc}.} The video hook functionality is designed (mostly) for live video. It allows the video to be modified or examined between the decoder and the encoder. @@ -67,18 +73,27 @@ with the full path to the font file, as in: @end example where 20 is the point size. +You can specify the filename to read RGB color names from. If it is not +specified, these defaults are used: @file{/usr/share/X11/rgb.txt} and +@file{/usr/lib/X11/rgb.txt} + Options: @multitable @columnfractions .2 .8 +@item @option{-C <rgb.txt>} @tab The filename to read RGB color names from @item @option{-c <color>} @tab The color of the text @item @option{-F <fontname>} @tab The font face and size @item @option{-t <text>} @tab The text @item @option{-f <filename>} @tab The filename to read text from -@item @option{-x <expresion>} @tab x coordinate of text or image -@item @option{-y <expresion>} @tab y coordinate of text or image +@item @option{-x <expression>}@tab x coordinate of text or image +@item @option{-y <expression>}@tab y coordinate of text or image @item @option{-i <filename>} @tab The filename to read a image from +@item @option{-R <expression>}@tab Value for R color +@item @option{-G <expression>}@tab Value for G color +@item @option{-B <expression>}@tab Value for B color +@item @option{-A <expression>}@tab Value for Alpha channel @end multitable -Expresions are functions of these variables: +Expressions are functions of these variables: @multitable @columnfractions .2 .8 @item @var{N} @tab frame number (starting at zero) @item @var{H} @tab frame height @@ -137,6 +152,30 @@ Usage examples: a newline are treated as end-of-file. To create blank lines, use lines that consist of space characters only. + # Scrolling credits with custom color from a text file + ffmpeg -i input.avi -vhook \ + 'vhook/imlib2.so -C rgb.txt -c CustomColor1 -F VeraBd.ttf/16 -x 100 -y -1.0*N -f credits.txt' \ + -sameq output.avi + + This example does the same as the one above, but specifies an rgb.txt file + to be used, which has a custom-made color in it. + + # Variable colors + ffmpeg -i input.avi -vhook \ + 'vhook/imlib2.so -t Hello -R abs(255*sin(N/47*PI)) -G abs(255*sin(N/47*PI)) -B abs(255*sin(N/47*PI))' \ + -sameq output.avi + + In this example, the color for the text goes up and down from black to + white. + + # Text fade-out + ffmpeg -i input.avi -vhook \ + 'vhook/imlib2.so -t Hello -A max(0,255-exp(N/47))' \ + -sameq output.avi + + In this example, the text fades out in about 10 seconds for a 25 fps input + video file. + # scrolling credits from a graphics file ffmpeg -sameq -i input.avi \ -vhook 'vhook/imlib2.so -x 0 -y -1.0*N -i credits.png' output.avi |