vf_lavfi: add libavfilter bridge

Requires recent FFmpeg/Libav git versions. Earlier versions will not
be supported, as the API is different. (A libavfilter version that
uses AVFrame instead of AVFilterBuffer is needed.)

Note that this is sort of useless, because the option parser prevents
you from making use of the full libavfilter graph syntax. This has to be
fixed later.

Most of the filter creation code (half of the config() function) has
been taken from avplay.c.

This code is not based on MPlayer's vf_lavfi. The MPlayer code doesn't
compile as it hasn't been updated through multiple libavfilter API
changes, making it completely useless as a starting point.

1 files changed, 44 insertions, 5 deletions

diff --git a/configure b/configure
index 57542fc804..b27d9b8fce 100755
--- a/configure
+++ b/configure
@@ -328,8 +328,9 @@ Optional features:
   --disable-libass-osd   disable OSD rendering with libass [autodetect]
   --enable-rpath         enable runtime linker path for extra libs [disabled]
   --disable-libpostproc  disable postprocess filter (vf_pp) [autodetect]
-  --enable-libavdevice   enable libavdevice demuxers [disabled]
-  --enable-libavfilter   enable libavfilter [disabled] [unused]
+  --disable-libavdevice  enable libavdevice demuxers [autodetect]
+  --disable-libavfilter  enable libavfilter [autodetect]
+  --disable-vf-lavfi     enable vf_lavfi libavfilter bridge [audodetect]
 
 Codecs:
   --enable-mng              enable MNG input support [autodetect]
@@ -487,7 +488,8 @@ _ass=auto
 _libass_osd=auto
 _rpath=no
 libpostproc=auto
-libavfilter=no
+libavfilter=auto
+vf_lavfi=auto
 libavdevice=no
 _stream_cache=yes
 _priority=no
@@ -702,6 +704,8 @@ for ac_option do
   --disable-libavdevice) libavdevice=no ;;
   --enable-libavfilter) libavfilter=auto ;;
   --disable-libavfilter) libavfilter=no ;;
+  --enable-vf-lavfi)    vf_lavfi=auto ;;
+  --disable-vf-lavfi)   vf_lavfi=no ;;
 
   --enable-enca)        _enca=yes       ;;
   --disable-enca)       _enca=no        ;;
@@ -2694,11 +2698,25 @@ fi
 echores "$_avutil_has_refcounting"
 
 
-echocheck "libavfilter >= 3.17.0"
+# libavfilter as it can be used by vf_lavfi is 3.45.101 in FFmpeg, and
+# 3.5.0 in Libav. Completely useless version numbers.
+echocheck "libavfilter"
 if test "$libavfilter" = auto ; then
     libavfilter=no
-    if pkg_config_add "libavfilter >= 3.17.0" ; then
+
+    cat > $TMPC <<EOF
+#include <libavfilter/avfilter.h>
+void vf_next_query_format() {}
+int main(void) {
+    avfilter_register_all();
+    vf_next_query_format();
+    return 0;
+}
+EOF
+    if cc_check `$_pkg_config libavfilter --cflags --libs` && pkg_config_add "libavfilter" ; then
         libavfilter=yes
+    else
+        res_comment="not found or broken"
     fi
 fi
 if test "$libavfilter" = yes ; then
@@ -2709,6 +2727,25 @@ fi
 echores "$libavfilter"
 
 
+echocheck "using libavfilter through vf_lavfi"
+if test "$vf_lavfi" = auto ; then
+    vf_lavfi=no
+    if test "$libavfilter" = yes ; then
+        if test "$_avutil_has_refcounting" = no ; then
+            res_comment="libavutil too old"
+        else
+            vf_lavfi=yes
+        fi
+    fi
+fi
+if test "$vf_lavfi" = yes ; then
+    def_vf_lavfi='#define CONFIG_VF_LAVFI 1'
+else
+    def_vf_lavfi='#undef CONFIG_VF_LAVFI'
+fi
+echores "$vf_lavfi"
+
+
 echocheck "libavdevice >= 54.0.0"
 if test "$libavdevice" = auto ; then
     libavdevice=no
@@ -3044,6 +3081,7 @@ LCMS2 = $_lcms2
 LIBPOSTPROC = $libpostproc
 LIBAVDEVICE = $libavdevice
 LIBAVFILTER = $libavfilter
+VF_LAVFI = $vf_lavfi
 LIBSMBCLIENT = $_smb
 LIBQUVI = $_libquvi
 LIBTHEORA = $_theora
@@ -3200,6 +3238,7 @@ $def_avutil_has_qp_api
 $def_libpostproc
 $def_libavdevice
 $def_libavfilter
+$def_vf_lavfi
 
 
 /* Audio output drivers */