In this iteration I've made the following changes, based on the received feedback:
- No external tools are needed by the build system. - The external filters should be put in ext/libavfilter. Anything there will be included. - The build system will execute a file called `configure.sh` in the directory of the external filter. This script has access to the functions and variables defined on `./configure`, as it's included via `.` on sh. - I will document the "API" for the external filters as soon the approach is approved, but an example of filter can be found at https://gitlab.com/leandrosansilva/ffmpeg-extra-filter-example . If you are unhappy with the example code hosted on gitlab.com, I can move it elsewhere where it gets easier for you to have access to the code. - Essentially, an external filter is composed by at least a `configure.sh` and a `Makefile`. I really hope this can be the last iteration, as I ran out of ideas on how to simplify the process, so please let me know your thoughts :-) Leandro On 3/24/25 16:56, Leandro Santiago wrote: > This is a POC/prototype that aims to enable out of tree filters on > FFmpeg. > > Here is how to test it, with an example filter: > > ``` > mkdir -p ext/libavfilter > pushd ext/libavfilter > git clone https://gitlab.com/leandrosansilva/ffmpeg-extra-filter-example > example > popd > ``` > > Then compile ffmpeg as usual: > > ``` > ./configure && make && make install > ``` > > Now you can use the new filters: > > ``` > ffplay /path/to/file.webm -vf 'foo,bar' > ``` > > What works: > > - Building C based filters with no extra, or simple dependencies. > - Multiple filters in the same object file. > > What was not implemented: > > - I believe it would be useful to check if the license of the filter is > compatible with the license used to build FFmpeg. > > - Only extra filters written in C (maybe C++?) are supported for now. > One of my goals is to enable Rust as well. > > - Documentation > > - There should be a way to have optional dependencies, for filters that > can have multiple "backends", for instance, to be chosen at build time. > > Signed-off-by: Leandro Santiago <leandrosansi...@gmail.com> > --- > .gitignore | 3 ++ > configure | 60 ++++++++++++++++++++++++++++++++++++++-- > libavfilter/Makefile | 4 +++ > libavfilter/allfilters.c | 1 + > 4 files changed, 66 insertions(+), 2 deletions(-) > > diff --git a/.gitignore b/.gitignore > index 430abaf91b..7d66dee516 100644 > --- a/.gitignore > +++ b/.gitignore > @@ -44,3 +44,6 @@ > /tools/python/__pycache__/ > /libavcodec/vulkan/*.c > /libavfilter/vulkan/*.c > +/ffbuild/external-filters.mak > +/libavfilter/external_filters_extern.h > +/ext > diff --git a/configure b/configure > index 2fdbe8cbbe..317862fa1a 100755 > --- a/configure > +++ b/configure > @@ -1798,6 +1798,7 @@ AVDEVICE_COMPONENTS=" > > AVFILTER_COMPONENTS=" > filters > + external_filters > " > > AVFORMAT_COMPONENTS=" > @@ -4086,7 +4087,7 @@ swscale_deps="avutil" > swscale_suggest="libm stdatomic" > > avcodec_extralibs="pthreads_extralibs iconv_extralibs dxva2_extralibs > liblcevc_dec_extralibs lcms2_extralibs" > -avfilter_extralibs="pthreads_extralibs" > +avfilter_extralibs="pthreads_extralibs external_filters_extralibs" > avutil_extralibs="d3d11va_extralibs d3d12va_extralibs mediacodec_extralibs > nanosleep_extralibs pthreads_extralibs vaapi_drm_extralibs > vaapi_x11_extralibs vaapi_win32_extralibs vdpau_x11_extralibs" > > # programs > @@ -4324,10 +4325,15 @@ ALL_COMPONENTS=" > $AVFORMAT_COMPONENTS_LIST > " > > -for n in $COMPONENT_LIST; do > +enable_component() { > + n="$1" > v=$(toupper ${n%s})_LIST > eval enable \$$v > eval ${n}_if_any="\$$v" > +} > + > +for n in $COMPONENT_LIST; do > + enable_component "$n" > done > > enable $ARCH_EXT_LIST > @@ -7463,6 +7469,56 @@ elif enabled iconv; then > check_func_headers iconv.h iconv || check_lib iconv iconv.h iconv -liconv > fi > > +# Handle external filters from the directory ext/libavfilter > + > +echo "" > libavfilter/external_filters_extern.h > +echo "" > ffbuild/external-filters.mak > + > +EXTERNAL_FILTER_LIST="" > + > +# This function is used by the external filters' configure.sh script to > register the filters > +register_external_filter_symbol() { > + EXT_FILTER_SYMBOL="$1" > + EXTERNAL_FILTER_LIST="$EXTERNAL_FILTER_LIST $(echo $EXT_FILTER_SYMBOL | > sed 's/^ff_[avfsinkrc]\{2,5\}_\([[:alnum:]_]\{1,\}\)/\1_filter/')" > + > + eval "$(echo "$EXT_FILTER_SYMBOL" | sed > 's/^ff_\([avfsinkrc]\{2,5\}\)_\([[:alnum:]]\{1,\}\)$/full_filter_name_\2=\1_\2/')" > + > + echo "extern const FFFilter $EXT_FILTER_SYMBOL;" >> > libavfilter/external_filters_extern.h > + > + echo "EXTERNAL_FILTER_$(\ > + echo $EXT_FILTER_SYMBOL \ > + | sed 's/^ff_[avfsinkrc]\{2,5\}_\([[:alnum:]]\{1,\}\)$/\1/' \ > + | tr a-z A-Z \ > + )_LOCATION = $CURRENT_EXT_FILTER_LOCATION" >> > ffbuild/external-filters.mak > +} > + > +if [ -d "ext/libavfilter" ]; then > + for f in ext/libavfilter/*; do > + [ -f "$f/configure.sh" ] || die "Mandatory file $f/configure.sh not > found" > + [ -f "$f/Makefile" ] || die "Mandatory file $f/Makefile not found" > + CURRENT_EXT_FILTER_LOCATION="$f" > + . "$f/configure.sh" || die "Could not configure external filter at > $f" > + echo "include $f/Makefile" >> ffbuild/external-filters.mak > + done > + > + enable_component external_filters > +fi > + > +FILTER_LIST=" > + $FILTER_LIST > + $EXTERNAL_FILTER_LIST > +" > + > +AVFILTER_COMPONENTS_LIST=" > + $AVFILTER_COMPONENTS_LIST > + $EXTERNAL_FILTER_LIST > +" > + > +ALL_COMPONENTS=" > + $ALL_COMPONENTS > + $EXTERNAL_FILTER_LIST > +" > + > enabled debug && add_cflags -g"$debuglevel" && add_asflags -g"$debuglevel" > > # add some useful compiler flags if supported > diff --git a/libavfilter/Makefile b/libavfilter/Makefile > index 7c0d879ec9..877b24c30f 100644 > --- a/libavfilter/Makefile > +++ b/libavfilter/Makefile > @@ -27,6 +27,10 @@ OBJS = allfilters.o > \ > include $(SRC_PATH)/libavfilter/dnn/Makefile > include $(SRC_PATH)/libavfilter/vulkan/Makefile > > +# external filters handling > +include $(SRC_PATH)/ffbuild/external-filters.mak > +EXTERNAL_FILTER_FLAGS = -I$(PWD) -I$(PWD)/libavfilter > + > OBJS-$(HAVE_LIBC_MSVCRT) += file_open.o > OBJS-$(HAVE_THREADS) += pthread.o > > diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c > index 740d9ab265..c2d576e4be 100644 > --- a/libavfilter/allfilters.c > +++ b/libavfilter/allfilters.c > @@ -621,6 +621,7 @@ extern const FFFilter ff_vsrc_buffer; > extern const FFFilter ff_asink_abuffer; > extern const FFFilter ff_vsink_buffer; > > +#include "libavfilter/external_filters_extern.h" > #include "libavfilter/filter_list.c" > > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
