https://github.com/andreicherniaev/buildroot_x86_x264
Build Linux with x264 for non-SIMD x86 CPU
https://github.com/andreicherniaev/buildroot_x86_x264
buildroot example
Last synced: about 1 month ago
JSON representation
Build Linux with x264 for non-SIMD x86 CPU
- Host: GitHub
- URL: https://github.com/andreicherniaev/buildroot_x86_x264
- Owner: AndreiCherniaev
- License: apache-2.0
- Created: 2025-03-21T07:13:30.000Z (about 1 month ago)
- Default Branch: main
- Last Pushed: 2025-03-21T07:28:42.000Z (about 1 month ago)
- Last Synced: 2025-03-21T08:25:03.026Z (about 1 month ago)
- Topics: buildroot, example
- Language: Makefile
- Homepage:
- Size: 23.4 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
How to build Linux image with x264.
## Compare with qemu_x86_defconfig
Config [qemu_x86_x264_defconfig](my_external_tree/configs/qemu_x86_x264_defconfig) is based on [qemu_x86_defconfig](https://github.com/buildroot/buildroot/blob/e82217622ea4778148de82a4b77972940b5e9a9e/configs/qemu_x86_defconfig).
## Clone
```
git clone --remote-submodules --recurse-submodules -j8 https://github.com/AndreiCherniaev/buildroot_x86_x264.git
cd buildroot_x86_x264
```
## Synthesize MJPEG video
input.y4m video I plan use as input to test in x264's CLI. This step is optional, by default you will use already existing `input.y4m` file from this repo. This step is if you want to synthesize video again.
```
# sudo apt install ffmpeg
# mkdir -p my_external_tree/board/my_company/my_board/fs-overlay/root/
ffmpeg -f lavfi -i testsrc=size=384x288:rate=1:duration=3 -vcodec wrapped_avframe -pix_fmt yuv420p my_external_tree/board/my_company/my_board/fs-overlay/root/input.y4m
```
## Make image
In example I use qemu_x86_x264_defconfig
```
make clean -C buildroot
make BR2_EXTERNAL=$PWD/my_external_tree -C $PWD/buildroot qemu_x86_x264_defconfig
make -C buildroot
```
## Save non-default buildroot .config
To save non-default buildroot's buildroot/.config to $PWD/my_external_tree/configs/qemu_x86_x264_defconfig
```
make -C $PWD/buildroot savedefconfig BR2_DEFCONFIG=$PWD/my_external_tree/configs/qemu_x86_x264_defconfig
```
## Start in QEMU
This code is based on emulation [script1](https://github.com/buildroot/buildroot/blob/02540771bccf7b10c7daecce5f0e1e41a73c1e07/boot/grub2/readme.txt#L4) and [script2](https://github.com/buildroot/buildroot/blob/9e3d572ff532df945fbc282fed22d10098e5718b/board/pc/readme.txt), run the emulation:
```
qemu-system-i386 -M pc -kernel buildroot/output/images/bzImage -drive file=buildroot/output/images/rootfs.ext2,if=virtio,format=raw -append "rootwait root=/dev/vda console=tty1 console=ttyS0" -serial stdio -net nic,model=virtio -net user
```
Note: Optionally add `-nographic` to see output not in extra screen but in console terminal. Or `-display curses` to pseudographic.
## The test
Login in Linux as `root` and type:
```
# x264 --crf 24 -o o.mkv input.y4m
y4m [info]: 384x288p 1:1 @ 1/1 fps (cfr)
x264 [info]: using SAR=1/1
x264 [info]: using cpu capabilities: MMX2 SSE2 SSE3 Cache64
x264 [info]: profile High, level 2.1, 4:2:0, 8-bit
x264 [info]: frame I:1 Avg QP: 6.80 size: 4466
x264 [info]: frame P:1 Avg QP:21.09 size: 1247
x264 [info]: frame B:1 Avg QP: 9.16 size: 1092
x264 [info]: consecutive B-frames: 33.3% 66.7% 0.0% 0.0%
x264 [info]: mb I I16..4: 75.0% 3.9% 21.1%
x264 [info]: mb P I16..4: 4.2% 1.6% 7.6% P16..4: 3.2% 3.9% 0.2% 0.0% 0.0% skip:79.2%
x264 [info]: mb B I16..4: 2.1% 0.7% 1.6% B16..8: 6.2% 6.5% 0.9% direct: 1.6% skip:80.3% L0:53.0% L1:45.3% BI: 1.7%
x264 [info]: 8x8 transform intra:5.3% inter:68.6%
x264 [info]: coded y,uvDC,uvAC intra: 14.4% 35.8% 27.3% inter: 1.9% 7.2% 6.4%
x264 [info]: i16 v,h,dc,p: 81% 7% 7% 6%
x264 [info]: i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 72% 6% 12% 2% 0% 0% 0% 0% 8%
x264 [info]: i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 61% 18% 15% 2% 1% 1% 0% 2% 0%
x264 [info]: i8c dc,h,v,p: 48% 17% 30% 4%
x264 [info]: Weighted P-Frames: Y:0.0% UV:0.0%
x264 [info]: kb/s:18.15
encoded 3 frames, 16.20 fps, 20.03 kb/s
```
What's the problem? Look at `using cpu capabilities: MMX2 SSE2 SSE3 Cache64`, but in buildroot we selected pentium pro, so even MMX2 should not be available. See also [x264 SIMD asm](https://forum.doom9.org/showthread.php?t=185002)
## How to rebuild x264
In case of problems to fix it and then build again
```
make x264-dirclean -C buildroot
make x264-rebuild -C buildroot 2>&1 |tee x264.log
```
Then see log in `x264.log`