ASM Support

Build scripts try to enable available CPU optimizations. The table below records ASM/SIMD status where scripts explicitly set ASM, SIMD, hardware-acceleration, NEON, SSE, or related options.

Library	Android	iOS / iPadOS	macOS	tvOS	visionOS	Linux
dav1d	all: No	all: No	all: No	all: No	all: No	x86-64: Yes
ffmpeg	all except x86: Yes; x86: No1	all except x86-64, x86-64-mac-catalyst: Yes; x86-64, x86-64-mac-catalyst: No	arm64: Yes; x86-64: No	arm64, arm64-simulator: Yes; x86-64: No	all: Yes	x86-64: Yes
gmp	all: No	all: No	all: No	all: No	all: No	linux-gmp: Dep
gnutls	all except x86: Yes; x86: No	all: Yes	all: Yes	all: Yes	all: Yes	linux-gnutls: Dep
kvazaar	Not specified	all except x86-64, x86-64-mac-catalyst: Yes; x86-64, x86-64-mac-catalyst: No	arm64: Yes; x86-64: No	arm64, arm64-simulator: Yes; x86-64: No	all: Yes	Not specified
libaom	arm-v7a: Partial; others: Yes	arm slices: Yes; i386: Partial; x86-64, x86-64-mac-catalyst: No3	arm64: Yes; x86-64: No	arm64, arm64-simulator: Yes; x86-64: No	all: Yes	x86-64: Yes
libass	arm-v7a, arm-v7a-neon, arm64-v8a, x86: No; x86-64: Yes4	arm slices: No; x86-64, x86-64-mac-catalyst: No; i386: Yes	all: No	all: No	all: No	linux-libass: Dep
libjxl	all: Partial5	all: Partial5	all: Partial5	all: Partial5	all: Partial5	x86-64: Partial5
libjpeg-turbo	all: Yes	arm slices: Yes; i386, x86-64, x86-64-mac-catalyst: No; arm64e: Yes2	all: Yes	all: Yes	all: Yes	Not built
libpng	arm-v7a: Partial6; others: Yes	all: Yes	all: Yes	all: Yes	all: Yes	linux-zlib/system png deps: Dep
libtheora	all: Yes	Not specified	Not specified	Not specified	Not specified	linux-libtheora: Dep
libvpx	arm-v7a: Partial7; others: Yes	armv7, armv7s, i386: Yes; arm64-family: Partial8; x86-64-family: Partial	arm64: Partial8; x86-64: Partial	arm64, arm64-simulator: Partial8; x86-64: Partial	all: Partial8	linux-libvpx: Dep
libwebp	arm-v7a: No; others: Yes	all except x86-64-mac-catalyst: Yes; x86-64-mac-catalyst: No	all: Yes	all: Yes	all: Yes	linux-libwebp: Dep
nettle	assembler: No; arch crypto flags: Partial	assembler: No; arch crypto flags: Partial	assembler: No; arch crypto flags: Partial	assembler: No; arch crypto flags: Partial	assembler: No; arch crypto flags: Partial	Not built
openh264	arm-v7a: No; others: Yes	all except x86-64: Yes; x86-64: No9	arm64: Yes; x86-64: No9	arm64, arm64-simulator: Yes; x86-64: No9	all: Yes	x86-64: Yes
openssl	all: Yes	arch target selected; 64-bit NIST EC optimization depends on __uint128_t	arch target selected; 64-bit NIST EC optimization depends on __uint128_t	arch target selected; 64-bit NIST EC optimization depends on __uint128_t	arch target selected; 64-bit NIST EC optimization depends on __uint128_t	x86-64: Yes
opus	all: Yes	all: Yes	all: Yes	all: Yes	all: Yes	linux-opus: Dep
soxr	Not specified	arm64*: Partial; others: Not specified	arm64: Partial; x86-64: Not specified	arm64, arm64-simulator: Partial; x86-64: Not specified	all: Partial	linux-soxr: Dep
speex	x86, x86-64: Yes; arm: Not specified	x86-family: Yes; arm: Not specified	x86-64: Yes; arm64: Not specified	x86-64: Yes; arm: Not specified	arm: Not specified	linux-speex: Dep
vo-amrwbenc	arm-v7a-neon: Yes; others: Not specified	Not specified	Not specified	Not specified	Not specified	linux-vo-amrwbenc: Dep
vvenc	arm-v7a: No; arm-v7a-neon, arm64-v8a: Yes; x86: Not specified	Not specified	Not specified	Not specified	Not specified	x86-64: Not specified
x264	all except x86: Yes; x86: No10	arm slices: Yes; i386, x86-64-family: No	arm64: Yes; x86-64: No	arm64, arm64-simulator: Yes; x86-64: No	all: Yes	x86-64: Yes
x265	arm-v7a, arm-v7a-neon, x86: No; arm64-v8a, x86-64: Yes	armv7, armv7s, x86-64: Yes; arm64*, i386, x86-64-mac-catalyst: No	arm64: No; x86-64: Yes	arm64, arm64-simulator: No; x86-64: Yes	all: No	linux-x265: Dep
xvidcore	all except x86: Yes; x86: No11	arm slices: Yes; i386, x86-64-family: No	arm64: Yes; x86-64: No	arm64, arm64-simulator: Yes; x86-64: No	all: Yes	linux-xvidcore: Dep
zimg	Not specified	armv7, armv7s: No; others: Yes	all: Yes	all: Yes	all: Yes	Not specified

Legend:

Value	Meaning
Yes	ASM/SIMD is explicitly enabled by the script, or the script preserves an ASM-enabled build path.
No	ASM/SIMD is explicitly disabled by the script.
Partial	Some ASM/SIMD families are enabled while others are explicitly disabled.
Dep	Linux system dependency; ASM status is not known from these scripts.
Not specified	The script does not explicitly set ASM/SIMD-related options.
Not built	No build script exists for that platform in this project.

Notes

1. Android ffmpeg disables asm on x86 because the script references FFmpeg ticket 4928.
2. jpeg leaves the CMake architecture list empty for arm64e because libjpeg-turbo matches it as arm64, but arm64e is not a supported SIMD CPU type.
3. Apple libaom patches aom_ports to disable asm on x86-64-family slices.
4. Android libass disables asm on x86 because enabling it causes text relocations in libavfilter.so.
5. libjxl disables AVX512, AVX512_SPR, AVX512_ZEN4, sizeless vectors, and forced NEON in scripts.
6. Android libpng does not enable hardware optimizations on arm-v7a because that makes the build try ARM-NEON instructions and breaks compilation.
7. Android libvpx disables NEON on arm-v7a because runtime CPU detection enables NEON for armv7 CPU.
8. Apple libvpx enables NEON on arm64-family slices but disables --enable-neon-asm because that option is ARMv7-style 32-bit only; arm64e also disables NEON dotprod due ptrauth issues.
9. Apple openh264 script says ASM is enabled for all iOS architectures except x86-64.
10. Android x264 disables asm on x86 because enabling it causes text relocations in libavfilter.so.
11. Android xvidcore disables assembly on x86 because enabling it causes text relocations in libavcodec.so.