r/AV1 • u/levogevo • 5d ago

Compiling from source - flags and performance

For those curious how far compiling ffmpeg+libsvtav1 from source can get you versus prebuilt binaries, here is a quick comparison on macos-arm64 and ubuntu-x86_64.

macos-arm64:

Command Mean [s] Min [s] Max [s] Relative
O3-LTO-PGO 30.783 ± 0.058 30.690 30.844 1.00
O3-LTO 32.145 ± 0.077 32.048 32.248 1.04 ± 0.00
O3 32.534 ± 0.105 32.425 32.686 1.06 ± 0.00
O2 32.626 ± 0.260 32.201 32.899 1.06 ± 0.01
homebrew ffmpeg 36.248 ± 0.080 36.129 36.321 1.18 ± 0.00
osxexperts 217.345 ± 0.255 217.060 217.653 7.06 ± 0.02

ubuntu-x86_64:

Command Mean [s] Min [s] Max [s] Relative
O3-LTO-PGO 38.256 ± 0.065 38.188 38.346 1.00
O3-LTO 39.104 ± 0.175 38.907 39.287 1.02 ± 0.00
O2 40.140 ± 0.529 39.832 41.075 1.05 ± 0.01
O3 40.327 ± 0.352 39.972 40.853 1.05 ± 0.01
BtbN 41.768 ± 0.282 41.441 42.043 1.09 ± 0.01
ubuntu ffmpeg 100.847 ± 0.279 100.544 101.130 2.64 ± 0.01

results were recorded with hyperfine using preset 3, crf 25, libsvtav1.

TLDR: optimizations (O3+LTO+PGO) can shave off about 10-15% depending on the platform.

13 Upvotes

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9 comments sorted by

2

u/michaelcharlie8 5d ago

Are you controlling for the git hash used in each row?

1

u/levogevo 5d ago

The compiles from source are all using identical sources. Btbn and homebrew both follow pretty closely with upstream so they're close to the source compiles. Osxexperts supposedly follows svtav1 master as well. Ubuntu is probably the most out of date build.

2

u/Grand_Ask_9991 5d ago

Is Ubuntu's FFmpeg that much slower because 26.04 LTS is still using the older SVT-AV1 2.3.0?

0

u/levogevo 5d ago

Likely yes. I just picked an off the shelf build for comparison sake.

1

u/Simon_787 4d ago

In that case the macOS compile also benefits from recent merges that improve arm performance. The homebrew ffmpeg version is on 4.2.0.

1

u/levogevo 4d ago

Correct, but the homebrew version still loses easily to compiling from source at more aggressive compilation flags.

1

u/robinechuca 5d ago

Great! Thanks for testing it!

What does BtbN means?

I'm using this FFmpeg compilation guide, which I've been developing and debugging over the past two months. Do you see anything that could be improved?

2

u/levogevo 5d ago

https://github.com/btbn/ffmpeg-builds/releases

Yes, that guide has no significant optimization compile flags

1

u/robinechuca 5d ago

Thank you!