Feat: Add BaseHostNode

[jkbmrz]

Purpose

Based on the comment in #192, we are missing an abstract class with platform extraction functionality. Adding it limits code repetition in host nodes and centralizes the control over the ImgFrame.Type settings for individual platforms.

Specification

Adding the BaseHostNode, an abstract class with platform extraction functionality, and using it as a parent in all of our host nodes.

Dependencies & Potential Impact

None

Deployment Plan

None

Testing & Validation

Tested by running the depthai-experiments/neural-networks/generic-example using the midas-v2-1:small-256x192 model both on RVC2 and RVC4.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 89.65517% with 3 lines in your changes missing coverage. Please review.

Project coverage is 51.96%. Comparing base (5c6073a) to head (2e978e3).

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
depthai_nodes/node/base_host_node.py	81.25%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #202      +/-   ##
==========================================
+ Coverage   51.80%   51.96%   +0.15%     
==========================================
  Files          81       82       +1     
  Lines        4799     4821      +22     
==========================================
+ Hits         2486     2505      +19     
- Misses       2313     2316       +3     

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[kkeroo]

LGTM, just thinking if we should rename this base class ImageFrameSender to more general name BaseHostNode or something. Because its a general class and not a "sender" and it might come useful in other nodes aswell.

[klemen1999]

Maybe BaseImgFrameSender or BaseFrameSender? Because it is a base abstract class that all other nodes that send out frames could inherit from, but I wouldn't make it a BaseHostNode because that implies all host nodes inherit from it IMO

[kkeroo]

Ok, but I dont see why other nodes couldnt inherit from this node. _platform attribute could be used in other nodes as well, similar for _frame_type?

[jkbmrz]

Ok, but I dont see why other nodes couldnt inherit from this node. _platform attribute could be used in other nodes as well, similar for _frame_type?

That's true. There is currently no direct usage of the platform parameter in other nodes but there might come more where this will come handy (and they might not output the ImgFrames). I'd thus agree we rename the node to BaseHostNode and use it as a parent class in all of our host nodes. This might also allow us to abstract more things in the future.

[klemen1999]

Actually I agree yeah, I think it makes sens to make it into an overall base node. Let's make sure every other inherits from it as
well

[dominik737]

This might also allow us to abstract more things in the future.

I think having custom base node is good to abstract some very very common things.

On the other hand I would not put too much logic that is not common/true for all our nodes. That would then over time lead to the node being very bulky, unclear and with many responsibilities as opposed to single responsibility.

[jkbmrz]

I've renamed the node in ab06069 to BaseHostNode. I think this works nicely as it also follows the structure we have for the parsers (inheriting from the BaseParser).