avfilter/scale: add animation support

Width and height expressions in scale and scale2ref filters can now
reference frame index, timestamp and packet position.

1 files changed, 26 insertions, 0 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 2caebcdcd3..98b695eca8 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -16139,6 +16139,19 @@ pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
 @item ovsub
 horizontal and vertical output chroma subsample values. For example for the
 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+
+@item n
+The (sequential) number of the input frame, starting from 0.
+Only available with @code{eval=frame}.
+
+@item t
+The presentation timestamp of the input frame, expressed as a number of
+seconds. Only available with @code{eval=frame}.
+
+@item pos
+The position (byte offset) of the frame in the input stream, or NaN if
+this information is unavailable and/or meaningless (for example in case of synthetic video).
+Only available with @code{eval=frame}.
 @end table
 
 @subsection Examples
@@ -16362,6 +16375,19 @@ The main input video's display aspect ratio. Calculated from
 The main input video's horizontal and vertical chroma subsample values.
 For example for the pixel format "yuv422p" @var{hsub} is 2 and @var{vsub}
 is 1.
+
+@item main_n
+The (sequential) number of the main input frame, starting from 0.
+Only available with @code{eval=frame}.
+
+@item main_t
+The presentation timestamp of the main input frame, expressed as a number of
+seconds. Only available with @code{eval=frame}.
+
+@item main_pos
+The position (byte offset) of the frame in the main input stream, or NaN if
+this information is unavailable and/or meaningless (for example in case of synthetic video).
+Only available with @code{eval=frame}.
 @end table
 
 @subsection Examples