Is it standard to grayscale?

[slerman12]

I've been using rgb.

gym.make(env, obs_type='rgb')

However, StableBaselines3 uses grayscale.

Which one is preferred/standard?

Thanks.

[JesseFarebro]

Hi @slerman12, the standard methodology since the release of DQN is that the agent will observe grayscaled frames, down sampled to 84x84 and stacked in the depth channel with the previous 4 observations.

There's a lot of nuance in the preprocessing stack for the ALE. I would highly suggest using something that's tried and tested. I would recommend looking at:

• dqn_zoo's processors.AtariEnvironmentWrapper (this is what I'd consider the gold-standard implementation).
• Dopamine's atari_lib.AtariPreprocessing
• Acme's atari_wrapper.AtariWrapper

We provide the option to retrieve RGB observations from gym.make but in the future I plan on building the complete preprocessing pipeline into the ALE itself so there isn't all these different postprocessing implementations.

Let me know if you have any other questions about this, I know it can be confusing, the most common questions I receive are around postprocessing.