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authorMarton Balint <cus@passwd.hu>2018-06-29 00:03:04 +0200
committerMarton Balint <cus@passwd.hu>2018-09-09 21:21:42 +0200
commit43d3b61abeb7bf35dfbe33f790c1cca0b628c97f (patch)
tree965cea71f0212106377303e866dcf1c76ab77d9b /doc
parent4737387d288d1e87e7c7df6203a42d6b1e88231e (diff)
downloadffmpeg-43d3b61abeb7bf35dfbe33f790c1cca0b628c97f.tar.gz
avfilter/f_cue: add cue and acue filters
To delay filtering until a given wallclock timestamp. Signed-off-by: Marton Balint <cus@passwd.hu>
Diffstat (limited to 'doc')
-rw-r--r--doc/filters.texi36
1 files changed, 36 insertions, 0 deletions
diff --git a/doc/filters.texi b/doc/filters.texi
index 37e79d34e1..5ccd6e0863 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -551,6 +551,11 @@ Set LFO range.
Set LFO rate.
@end table
+@section acue
+
+Delay audio filtering until a given wallclock timestamp. See the @ref{cue}
+filter.
+
@section adeclick
Remove impulsive noise from input audio.
@@ -6987,6 +6992,37 @@ indicates 'never reset', and returns the largest area encountered during
playback.
@end table
+@anchor{cue}
+@section cue
+
+Delay video filtering until a given wallclock timestamp. The filter first
+passes on @option{preroll} amount of frames, then it buffers at most
+@option{buffer} amount of frames and waits for the cue. After reaching the cue
+it forwards the buffered frames and also any subsequent frames coming in its
+input.
+
+The filter can be used synchronize the output of multiple ffmpeg processes for
+realtime output devices like decklink. By putting the delay in the filtering
+chain and pre-buffering frames the process can pass on data to output almost
+immediately after the target wallclock timestamp is reached.
+
+Perfect frame accuracy cannot be guaranteed, but the result is good enough for
+some use cases.
+
+@table @option
+
+@item cue
+The cue timestamp expressed in a UNIX timestamp in microseconds. Default is 0.
+
+@item preroll
+The duration of content to pass on as preroll expressed in seconds. Default is 0.
+
+@item buffer
+The maximum duration of content to buffer before waiting for the cue expressed
+in seconds. Default is 0.
+
+@end table
+
@anchor{curves}
@section curves