The NXP BSP provides support for decoding video using the embedded Hantro G1/G2 IP cores. This is provided by some NXP provided libraries and gstreamer plugins.
In addition to the NXP provided gstreamer plugins, there is also gstreamer-imx which is provided by a third party. As you noticed, support was just added for the i.MX8M in the last several weeks. I've successfully tried the gstreamer-imx plugins.
Looking further down the road, there is ongoing work (outside of NXP) to develop a clean slate solution for video playback with the Hantro G1/G2 IP cores in the i.MX8M by a group of developers. The Hantro video decoders are not unique to the i.MX8M. They are also in several Rockchip designs and as such a common driver stack is being developed that works regardless of the SoC being used. This stack will likely leverage the V4L2 API. You can see some work down this path at the following URL:
[PATCH v2 0/9] Rename Rockchip VPU driver to Hantro, add initial i.MX8M support