Performance

ffmpeg.wasm uses transpiled FFmpeg C source code to WebAssembly code, it is for certain that ffmpeg.wasm won't perform as good as FFmpeg as it is not fully optimized at the moment. (Even in ffmpeg.wasm multithread version). In this section we provide a short comparison, so that you can make decision based on your needs:

Environment

• CPU: 8 × 11th Gen Intel® Core™ i5-1135G7 @ 2.40GHz
• Memory: 15.6 GiB of RAM
• OS: Manjaro Linux 6.1.44-1-MANJARO (64-bit)
• Browser: Google Chrome Version 116.0.5845.96 (Official Build) (64-bit)
• FFmpeg: n5.1.2

Comparison

Setup:

• Each command is executed 5 times.
• Only ffmpeg.exec() time is measured.
• Candidates
  • FFmpeg: native FFmpeg, considered as baseline.
  • core: ffmpeg.wasm single thread version.
  • core-mt: ffmpeg.wasm multi thread version.

$ ffmpeg -i input.webm output.mp4

#	FFmpeg	core v0.12.3	core-mt v0.12.3
Avg	5.2 sec	128.8 sec (0.04x)	60.4 sec (0.08x)
Max	5.3 sec	130.7 sec	63.9 sec
Min	5.1 sec	126.6 sec	59 sec