multiple definition error when building a project using mpp and libvpx #580
Description
Rockchip mpp uses functions with the same name as libvpx. This leads to a multiple definition error when using both, mpp and libvpx, in a project together. Here is the build output when trying to build ffmpeg-rockchip from @nyanmisaka including libvpx:
/opt/ct-ng/lib/gcc/aarch64-ffbuild-linux-gnu/13.2.0/../../../../aarch64-ffbuild-linux-gnu/bin/ld/opt/ct-ng/lib/gcc/aarch64-ffbuild-linux-gnu/13.2.0/../../../../aarch64-ffbuild-linux-gnu/bin/ld: /opt/ffbuild/lib/librockchip_mpp.a(hal_vp9d_com.c.o):: (.rodata+0x0): multiple definition of `vp9_kf_partition_probs'; /opt/ffbuild/lib/libvpx.a(vp9_entropymode.c.o):(.rodata+0x190)/opt/ffbuild/lib/librockchip_mpp.a(hal_vp9d_com.c.o):(.rodata+0x0): multiple definition of `vp9_kf_partition_probs'; /opt/ffbuild/lib/libvpx.a(vp9_entropymode.c.o):(: first defined here
/opt/ct-ng/lib/gcc/aarch64-ffbuild-linux-gnu/13.2.0/../../../../aarch64-ffbuild-linux-gnu/bin/ld: /opt/ffbuild/lib/librockchip_mpp.a(hal_vp9d_com.c.o):(.rodata.rodata+0x30): multiple definition of `vp9_kf_uv_mode_prob'; /opt/ffbuild/lib/libvpx.a(vp9_entropymode.c.o):(.rodata+0x+0x190): first defined here
/opt/ct-ng/lib/gcc/aarch64-ffbuild-linux-gnu/13.2.0/../../../../aarch64-ffbuild-linux-gnu/bin/ld1c0: /opt/ffbuild/lib/librockchip_mpp.a(hal_vp9d_com.c.o):(.rodata+0x)30): multiple definition of `vp9_kf_uv_mode_prob: first defined here'; /opt/ffbuild/lib/libvpx.a(vp9_entropymode.c.o):(.rodata+0x
1c0): first defined here/opt/ct-ng/lib/gcc/aarch64-ffbuild-linux-gnu/13.2.0/../../../../aarch64-ffbuild-linux-gnu/bin/ld
/opt/ct-ng/lib/gcc/aarch64-ffbuild-linux-gnu/13.2.0/../../../../aarch64-ffbuild-linux-gnu/bin/ld: /opt/ffbuild/lib/librockchip_mpp.a(hal_vp9d_com.c.o):(.rodata: +0xb0): multiple definition of `vp9_kf_y_mode_prob'; /opt/ffbuild/lib/libvpx.a(vp9_entropymode.c.o):(.rodata/opt/ffbuild/lib/librockchip_mpp.a(hal_vp9d_com.c.o):(+0x.rodata220): first defined here+0x
b0): multiple definition of `vp9_kf_y_mode_prob'; /opt/ffbuild/lib/libvpx.a(vp9_entropymode.c.o):(.rodata+0x220): first defined here
/opt/ct-ng/lib/gcc/aarch64-ffbuild-linux-gnu/13.2.0/../../../../aarch64-ffbuild-linux-gnu/bin/ld: /opt/ffbuild/lib/librockchip_mpp.a(hal_vp9d_com.c.o):(.rodata+0x0): multiple definition of `vp9_kf_partition_probs'; /opt/ffbuild/lib/libvpx.a(vp9_entropymode.c.o):(.rodata+0x190): first defined here
/opt/ct-ng/lib/gcc/aarch64-ffbuild-linux-gnu/13.2.0/../../../../aarch64-ffbuild-linux-gnu/bin/ld: /opt/ffbuild/lib/librockchip_mpp.a(hal_vp9d_com.c.o):(.rodata+0x30): multiple definition of `vp9_kf_uv_mode_prob'; /opt/ffbuild/lib/libvpx.a(vp9_entropymode.c.o):(.rodata+0x1c0): first defined here
/opt/ct-ng/lib/gcc/aarch64-ffbuild-linux-gnu/13.2.0/../../../../aarch64-ffbuild-linux-gnu/bin/ld: /opt/ffbuild/lib/librockchip_mpp.a(hal_vp9d_com.c.o):(.rodata+0xb0): multiple definition of `vp9_kf_y_mode_prob'; /opt/ffbuild/lib/libvpx.a(vp9_entropymode.c.o):(.rodata+0x220): first defined here
collect2: error: ld returned 1 exit status
make: *** [Makefile:133: ffmpeg_g] Error 1
make: *** Waiting for unfinished jobs....
collect2: error: ld returned 1 exit status
make: *** [Makefile:133: ffprobe_g] Error 1
collect2: error: ld returned 1 exit status
make: *** [Makefile:133: ffplay_g] Error 1
I propose to rename the functions that are also used in the libvpx project (maybe prefix them with mpp_).
It seems, that there were files copied from the libvpx project (similar to #530). Note, that libvpx is licensed under BSD-3-Clause license. As far as I know, this license allows to modify the source code of libvpx and include it in your project, but it obliges you to add a copy of the BSD license to your project. Maybe it is enough to just add the BSD license as a comment to the source code.