Attached a patch which adds a "skipblend" filter, which is similar to the framestep filter, but additionally blends frames together at each step, for a motion blur effect. The number of frames that are blended (i.e. the exposure time, in frames) can be set, allowing control over the strength of the motion blur. The filter has timeline support, and supports both 8-bit and 16-bit pixel formats. Tests and documentation included.
This can be used for instance to blend down high framerate footage to produce a high quality motion blur effect. Note that a similar effect is already possible by repeatedly chaining the tblend and framestep=step=2 filters; see for example: https://video.stackexchange.com/questions/16552/4x-resample-videoframes-using-ffmpeg But this is limited to steps that are powers of two, and this does not allow an intermediate exposure time. It's also slower. Issues addressed: fixed mips failure (reported by Michael), fixed potential overflow on systems where int is only 16 bits wide (reported by Moritz), fixed changelog entry position (reported by Moritz), moved code out of framestep and instead create new filter (requested by Paul & wm4, I agree this looks cleaner). In the documentation, I've also added links between framestep, tblend, and the new skipblend filter, to help users to find the right filter they are looking for. Feedback welcome as always. Kind regards, Matthias PS. For reference, previous submissions of this patch with discussion: https://ffmpeg.org/pipermail/ffmpeg-devel/2017-April/209794.html https://ffmpeg.org/pipermail/ffmpeg-devel/2017-May/211814.html Matthias C. M. Troffaes (1): avfilter: add skipblend filter Changelog | 1 + doc/filters.texi | 30 ++++ libavfilter/Makefile | 1 + libavfilter/allfilters.c | 1 + libavfilter/version.h | 2 +- libavfilter/vf_skipblend.c | 272 +++++++++++++++++++++++++++++++++ tests/fate/filter-video.mak | 12 ++ tests/ref/fate/filter-skipblend-anim-1 | 17 +++ tests/ref/fate/filter-skipblend-anim-2 | 17 +++ tests/ref/fate/filter-skipblend-gray-1 | 14 ++ tests/ref/fate/filter-skipblend-gray-2 | 13 ++ 11 files changed, 379 insertions(+), 1 deletion(-) create mode 100644 libavfilter/vf_skipblend.c create mode 100644 tests/ref/fate/filter-skipblend-anim-1 create mode 100644 tests/ref/fate/filter-skipblend-anim-2 create mode 100644 tests/ref/fate/filter-skipblend-gray-1 create mode 100644 tests/ref/fate/filter-skipblend-gray-2 -- 2.7.4 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
