Update for SAM 2.1

[drien]

This brings in the code changes and configs for the 2.1 updates directly from the original sam2 repo. Everything seems to work as expected with both of the 2 and 2.1 models. I just updated the variants to have a version prefix so there aren't breaking changes for users who've already integrated this with the 2.0 version.

I duplicated some of the tests to run with the 2.1 models as well and everything passes with both versions, but I've only done real-world testing using the 2.1 checkpoints.

[drien]

Also I've added in a fix for a mistaken dependency on pytest–since the download_weights() method was imported to the root util module, it was then imported when running from sam2 import load_model, so installing in an environment without pytest would crash with an ImportError. I've just removed that import and made the tests import directly from sam2.utils.download.

Reproduce:

$ docker run --rm -it python:3.11-bullseye  bash -il
# pip install samv2
...
# python
>>> from sam2 import load_model

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.11/site-packages/sam2/__init__.py", line 9, in <module>
    from .build_sam import load_model
  File "/usr/local/lib/python3.11/site-packages/sam2/build_sam.py", line 14, in <module>
    from .utils.misc import VARIANTS, variant_to_config_mapping
  File "/usr/local/lib/python3.11/site-packages/sam2/utils/__init__.py", line 7, in <module>
    from .download import download_weights
  File "/usr/local/lib/python3.11/site-packages/sam2/utils/download.py", line 5, in <module>
    import pytest
ModuleNotFoundError: No module named 'pytest'

Test Fix:

$ docker run --rm -it -v .:/opt/samv2 python:3.11-bullseye  bash -il
# pip install -e .
...
# python
>>> from sam2 import load_model
>>> 
>>> exit()
# pip3 install pytest
...
# pytest
=========================================================================================== test session starts ============================================================================================
platform linux -- Python 3.11.11, pytest-8.3.4, pluggy-1.5.0
rootdir: /opt/samv2
configfile: pyproject.toml
testpaths: tests
plugins: hydra-core-1.3.2
collected 15 items                                                                                                                                                                                         

tests/test_build_model.py ..^C

[SauravMaheshkar]

Are these new functions used somewhere? This fork was created with the aim to be a minimal version of the original codebase.

[SauravMaheshkar]

Any particular reason for removing this ? I created the get_sdp_backends function to support the newer backends if available on the system being used.

[SauravMaheshkar]

Huh this is interesting, I used ruff initially for sorting imports, it shouldn't re-organise like this.

[SauravMaheshkar]

maybe I'm being pedantic but just to confirm, this runs okay during forward inference? I don't see a .neck submodule.

[SauravMaheshkar]

Hey @drien thanks a lot for contributing ❤️ . Left a couple of review notes ☕