@end example
@end itemize
-@section aselect, select
-Select frames to pass in output.
-
-It accepts in input an expression, which is evaluated for each input
-frame. If the expression is evaluated to a non-zero value, the frame
-is selected and passed to the output, otherwise it is discarded.
-
-The expression can contain the following constants:
-
-@table @option
-@item n
-the sequential number of the filtered frame, starting from 0
-
-@item selected_n
-the sequential number of the selected frame, starting from 0
-
-@item prev_selected_n
-the sequential number of the last selected frame, NAN if undefined
-
-@item TB
-timebase of the input timestamps
-
-@item pts
-the PTS (Presentation TimeStamp) of the filtered video frame,
-expressed in @var{TB} units, NAN if undefined
-
-@item t
-the PTS (Presentation TimeStamp) of the filtered video frame,
-expressed in seconds, NAN if undefined
-
-@item prev_pts
-the PTS of the previously filtered video frame, NAN if undefined
-
-@item prev_selected_pts
-the PTS of the last previously filtered video frame, NAN if undefined
-
-@item prev_selected_t
-the PTS of the last previously selected video frame, NAN if undefined
-
-@item start_pts
-the PTS of the first video frame in the video, NAN if undefined
-
-@item start_t
-the time of the first video frame in the video, NAN if undefined
-
-@item pict_type @emph{(video only)}
-the type of the filtered frame, can assume one of the following
-values:
-@table @option
-@item I
-@item P
-@item B
-@item S
-@item SI
-@item SP
-@item BI
-@end table
-
-@item interlace_type @emph{(video only)}
-the frame interlace type, can assume one of the following values:
-@table @option
-@item PROGRESSIVE
-the frame is progressive (not interlaced)
-@item TOPFIRST
-the frame is top-field-first
-@item BOTTOMFIRST
-the frame is bottom-field-first
-@end table
-
-@item consumed_sample_n @emph{(audio only)}
-the number of selected samples before the current frame
-
-@item samples_n @emph{(audio only)}
-the number of samples in the current frame
-
-@item sample_rate @emph{(audio only)}
-the input sample rate
-
-@item key
-1 if the filtered frame is a key-frame, 0 otherwise
-
-@item pos
-the position in the file of the filtered frame, -1 if the information
-is not available (e.g. for synthetic video)
-
-@item scene @emph{(video only)}
-value between 0 and 1 to indicate a new scene; a low value reflects a low
-probability for the current frame to introduce a new scene, while a higher
-value means the current frame is more likely to be one (see the example below)
-
-@end table
-
-The default value of the select expression is "1".
-
-Some examples follow:
-
-@example
-# select all frames in input
-select
-
-# the above is the same as:
-select=1
-
-# skip all frames:
-select=0
-
-# select only I-frames
-select='eq(pict_type\,I)'
-
-# select one frame every 100
-select='not(mod(n\,100))'
-
-# select only frames contained in the 10-20 time interval
-select='gte(t\,10)*lte(t\,20)'
-
-# select only I frames contained in the 10-20 time interval
-select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
-
-# select frames with a minimum distance of 10 seconds
-select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
-
-# use aselect to select only audio frames with samples number > 100
-aselect='gt(samples_n\,100)'
-@end example
-
-Complete example to create a mosaic of the first scenes:
-
-@example
-ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
-@end example
-
-Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
-choice.
-
@section setdar, setsar
The @code{setdar} filter sets the Display Aspect Ratio for the filter
Below is a description of the currently available multimedia filters.
+@section aselect, select
+Select frames to pass in output.
+
+It accepts in input an expression, which is evaluated for each input
+frame. If the expression is evaluated to a non-zero value, the frame
+is selected and passed to the output, otherwise it is discarded.
+
+The expression can contain the following constants:
+
+@table @option
+@item n
+the sequential number of the filtered frame, starting from 0
+
+@item selected_n
+the sequential number of the selected frame, starting from 0
+
+@item prev_selected_n
+the sequential number of the last selected frame, NAN if undefined
+
+@item TB
+timebase of the input timestamps
+
+@item pts
+the PTS (Presentation TimeStamp) of the filtered video frame,
+expressed in @var{TB} units, NAN if undefined
+
+@item t
+the PTS (Presentation TimeStamp) of the filtered video frame,
+expressed in seconds, NAN if undefined
+
+@item prev_pts
+the PTS of the previously filtered video frame, NAN if undefined
+
+@item prev_selected_pts
+the PTS of the last previously filtered video frame, NAN if undefined
+
+@item prev_selected_t
+the PTS of the last previously selected video frame, NAN if undefined
+
+@item start_pts
+the PTS of the first video frame in the video, NAN if undefined
+
+@item start_t
+the time of the first video frame in the video, NAN if undefined
+
+@item pict_type @emph{(video only)}
+the type of the filtered frame, can assume one of the following
+values:
+@table @option
+@item I
+@item P
+@item B
+@item S
+@item SI
+@item SP
+@item BI
+@end table
+
+@item interlace_type @emph{(video only)}
+the frame interlace type, can assume one of the following values:
+@table @option
+@item PROGRESSIVE
+the frame is progressive (not interlaced)
+@item TOPFIRST
+the frame is top-field-first
+@item BOTTOMFIRST
+the frame is bottom-field-first
+@end table
+
+@item consumed_sample_n @emph{(audio only)}
+the number of selected samples before the current frame
+
+@item samples_n @emph{(audio only)}
+the number of samples in the current frame
+
+@item sample_rate @emph{(audio only)}
+the input sample rate
+
+@item key
+1 if the filtered frame is a key-frame, 0 otherwise
+
+@item pos
+the position in the file of the filtered frame, -1 if the information
+is not available (e.g. for synthetic video)
+
+@item scene @emph{(video only)}
+value between 0 and 1 to indicate a new scene; a low value reflects a low
+probability for the current frame to introduce a new scene, while a higher
+value means the current frame is more likely to be one (see the example below)
+
+@end table
+
+The default value of the select expression is "1".
+
+Some examples follow:
+
+@example
+# select all frames in input
+select
+
+# the above is the same as:
+select=1
+
+# skip all frames:
+select=0
+
+# select only I-frames
+select='eq(pict_type\,I)'
+
+# select one frame every 100
+select='not(mod(n\,100))'
+
+# select only frames contained in the 10-20 time interval
+select='gte(t\,10)*lte(t\,20)'
+
+# select only I frames contained in the 10-20 time interval
+select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
+
+# select frames with a minimum distance of 10 seconds
+select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
+
+# use aselect to select only audio frames with samples number > 100
+aselect='gt(samples_n\,100)'
+@end example
+
+Complete example to create a mosaic of the first scenes:
+
+@example
+ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
+@end example
+
+Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
+choice.
+
@section asendcmd, sendcmd
Send commands to filters in the filtergraph.
projects / ffmpeg / commitdiff