execution of ffmpeg is taking more time in gentoo than other

[rupeshforu3]

Hi I am Rupesh from India and I brought a new PC with AMD Ryzen zen3 5500GT and Asus prime 450 MK2 motherboard. I installed four Linux Operating Systems including gentoo linux and one Windows 11 Operating System. I installed ffmpeg tool along with libaom. Everything is working fine except there is something wrong with ffmpeg execution in Gentoo Linux.

I love working with Linux and Unix Operating Systems and I have lot of disk space and so I have installed four Linux Operating Systems and they are

1) Debian Linux testing Trixie
2) Fedora 40
3) Arch Linux
4) Gentoo Linux with systemd and desktop stage 3

At first I have installed Zen kernel through genkernel utility passing the parameter all.

After installation I have compiled the same ffmpeg source code which is cloned from git and with the same options which includes the following

--enable opencl
--enable opengl
--enable libaom
--enable AMF
--enable gnutils
Etc.,

I have some h264 mp4 files and I want to convert them into aom codec through ffmpeg and libaom.

I tested to convert those same files into aom codec using the same ffmpeg script but ffmpeg in gentoo Linux is taking too much time compared to ffmpeg in remaining Linux Operating Systems.

During the compilation of ffmpeg in gentoo linux I have installed packages related to amdgpu and rocm but unfortunately rocm-opencl-headers failed in installation.

After that I installed clinfo and ran it and it is showing message as Full profile, platform AMD etc.,.

Ffmpeg in other distributions is taking 45 minutes to convert 110 MB h264 mp4 to aom codec mp4 but unfortunately ffmpeg in Gentoo Linux is taking more than 100 minutes.

I can't understand what's wrong with ffmpeg in Gentoo Linux.

Even I have installed amdgpu_top_gui and opened it and it is showing a lot of information about my APU.

If I have not installed anything which is required for ffmpeg to run properly it must fall in compilation but it compiled successfully but it is not working fine.

Kindly try to suggest how to make ffmpeg to work properly and I am ready to provide any diagnostic information of the commands provided by you.

Regards,
Rupesh.
_________________
Regards,
Rupesh.

[stefantalpalaru]

Make sure you have this set up: https://wiki.gentoo.org/wiki/CPU_FLAGS_*

Since you manually built ffmpeg from source, instead of using an ebuild, I'm going to assume you're a beginner and tell you to also make sure you have sane CFLAGS and CXXFLAGS (like "-O3 -march=native").