video command fails... because of vapoursynth plugin missing?

[hmijail]

Maybe this is not ssimulacra2_rs's problem, but trying to run the video command in macOS, I got this error:

$ ssimulacra2_rs video v1.mp4 v2.mp4
thread 'main' panicked at /Users/mija/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ssimulacra2_rs-0.5.2/src/video.rs:251:63:
called `Result::unwrap()` on an `Err` value: An error occurred in VSScript

Caused by:
    Python exception: No attribute with the name lsmas exists. Did you mistype a plugin namespace or forget to install a plugin?
    
    Traceback (most recent call last):
      File "src/cython/vapoursynth.pyx", line 3387, in vapoursynth._vpy_evaluate
      File "src/cython/vapoursynth.pyx", line 3388, in vapoursynth._vpy_evaluate
      File "<undefined>", line 6, in <module>
      File "src/cython/vapoursynth.pyx", line 2895, in vapoursynth._CoreProxy.__getattr__
      File "src/cython/vapoursynth.pyx", line 2701, in vapoursynth.Core.__getattr__
    AttributeError: No attribute with the name lsmas exists. Did you mistype a plugin namespace or forget to install a plugin?
    
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Vapoursynth was installed through brew. After digging a bit looks like this error probably means that it's lacking a 2019 plugin named L-SMASH-Works that gives access to the MP4 library L-SMASH. However I don't see docs on how to install these, so I'm half-hoping that maybe there's some easier solution?

[hmijail]

After a bit more digging, I couldn't find a L-SMASH binary for macOS. Looks like it was available in Homebrew at some point but was removed in 2020.

As for the L-SMASH-Works plugin for Vapoursynth, the latest fork / repackaging I could find seems to only do x86/x64 for Windows and possibly Linux. Nothing for macOS / ARM (Apple Silicon).

FWIW, ssimulacra2_rs image works great on current macOS / Apple Silicon.

[FreezyLemon]

This is because av_metrics_decoders, which we use to decode the input videos, requires lsmashsource for decoding. Maybe it'd be better to prefer bestsource instead which should be available without a plugin, though that probably has some drawbacks too.

@shssoichiro Any ideas? Maybe some sort of auto-detection and fallback to bestsource if lsmash isn't available?