package/opencv3: drop support for ffmpeg

opencv3's code is not compatible with newer versions of ffmpeg, and
opencv3 is no longer maintained, so we have no choice but to disable
its ffmpeg support.

Fixes:

  https://autobuild.buildroot.net/results/9ae3911583cccb6362f33cd82e5eaafb059fdc76/

It's not clear which ffmpeg version bump broken the build exactly, but
this issue is definitely present in 2025.02.x as the following
defconfig fails to build in a similar way on 2025.02.x:

 BR2_aarch64=y
 BR2_TOOLCHAIN_EXTERNAL=y
 BR2_TOOLCHAIN_EXTERNAL_BOOTLIN=y
 BR2_TOOLCHAIN_EXTERNAL_BOOTLIN_AARCH64_GLIBC_STABLE=y
 BR2_PACKAGE_FFMPEG_NONFREE=y
 # BR2_PACKAGE_FFMPEG_FFMPEG is not set
 # BR2_PACKAGE_FFMPEG_INDEVS is not set
 # BR2_PACKAGE_FFMPEG_OUTDEVS is not set
 BR2_PACKAGE_OPENCV3=y
 BR2_PACKAGE_OPENCV3_LIB_VIDEOIO=y
 BR2_PACKAGE_OPENCV3_BUILD_PERF_TESTS=y
 BR2_PACKAGE_OPENCV3_WITH_FFMPEG=y
 BR2_PACKAGE_OPENCV3_INSTALL_DATA=y

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

Config.in.legacy

@@ -146,6 +146,13 @@ endif
 
 comment "Legacy options removed in 2026.02"
 
+config BR2_PACKAGE_OPENCV3_WITH_FFMPEG
+	bool "opencv3 ffmpeg support removed"
+	select BR2_LEGACY
+	help
+	  Support for OpenCV 3 ffmpeg support has been removed as it
+	  was no longer compatible with recent versions of ffmpeg.
+
 config BR2_PACKAGE_OPENCV3_WITH_PROTOBUF
 	bool "opencv3 protobuf support removed"
 	select BR2_LEGACY

package/ffmpeg/ffmpeg.mk

@@ -297,11 +297,11 @@ else
 FFMPEG_CONF_OPTS += --disable-mmal --disable-omx --disable-omx-rpi
 endif
 
-# To avoid a circular dependency only use opencv if opencv itself does
-# not depend on ffmpeg.
-ifeq ($(BR2_PACKAGE_OPENCV3_LIB_IMGPROC)x$(BR2_PACKAGE_OPENCV3_WITH_FFMPEG),yx)
+ifeq ($(BR2_PACKAGE_OPENCV3_LIB_IMGPROC),y)
 FFMPEG_CONF_OPTS += --enable-libopencv
 FFMPEG_DEPENDENCIES += opencv3
+# To avoid a circular dependency only use opencv if opencv itself does
+# not depend on ffmpeg.
 else ifeq ($(BR2_PACKAGE_OPENCV4_LIB_IMGPROC)x$(BR2_PACKAGE_OPENCV4_WITH_FFMPEG),yx)
 FFMPEG_CONF_OPTS += --enable-libopencv \
 	--extra-cflags=-I$(STAGING_DIR)/usr/include/opencv4

package/opencv3/Config.in

@@ -232,15 +232,6 @@ config BR2_PACKAGE_OPENCV3_BUILD_PERF_TESTS
 
 comment "3rd party support"
 
-config BR2_PACKAGE_OPENCV3_WITH_FFMPEG
-	bool "ffmpeg support"
-	depends on BR2_PACKAGE_FFMPEG_ARCH_SUPPORTS
-	select BR2_PACKAGE_BZIP2
-	select BR2_PACKAGE_FFMPEG
-	select BR2_PACKAGE_FFMPEG_SWSCALE
-	help
-	  Use ffmpeg from the target system.
-
 config BR2_PACKAGE_OPENCV3_WITH_GSTREAMER1
 	bool "gstreamer-1.x"
 	depends on BR2_USE_MMU # gstreamer1 -> libglib2

package/opencv3/opencv3.mk

@@ -212,6 +212,7 @@ OPENCV3_CONF_OPTS += \
 	-DWITH_1394=OFF \
 	-DWITH_CLP=OFF \
 	-DWITH_EIGEN=OFF \
+	-DWITH_FFMPEG=OFF \
 	-DWITH_GDAL=OFF \
 	-DWITH_GPHOTO2=OFF \
 	-DWITH_GSTREAMER_0_10=OFF \
@@ -232,13 +233,6 @@ OPENCV3_CONF_OPTS += \
 
 OPENCV3_DEPENDENCIES += host-pkgconf zlib
 
-ifeq ($(BR2_PACKAGE_OPENCV3_WITH_FFMPEG),y)
-OPENCV3_CONF_OPTS += -DWITH_FFMPEG=ON
-OPENCV3_DEPENDENCIES += ffmpeg bzip2
-else
-OPENCV3_CONF_OPTS += -DWITH_FFMPEG=OFF
-endif
-
 ifeq ($(BR2_PACKAGE_OPENCV3_WITH_GSTREAMER1),y)
 OPENCV3_CONF_OPTS += -DWITH_GSTREAMER=ON
 OPENCV3_DEPENDENCIES += gstreamer1 gst1-plugins-base