Onboard most SoCs there is what is referred to as a VPU (Video Processing Unit). The VPU is responsible for efficient encoding and decoding of videos. Video decoding can be extremely useful for example if you wanted to watch or stream video from your device without a high CPU utilization (which results from software decoding). Below information can be found on the various drivers that the SoCs used by PINE64 use, and their state of video decoding as a result of the mainline Linux drivers and software.
Cedrus and Hantro
In 2018 Bootlin launched a crowdfunding campaign to bring a open source Allwinner VPU driver to mainline Linux, which came to be called Cedrus. The Cedrus media driver (For Allwinner SOCs such as A64) supported by mainline Linux supports H.264 and H.265 video decoding as of Linux 5.10, and with 5.11 came VP8 decoding support and a H.264 stateless video decoder interface. For more information refer to the Sunxi wiki.
The Hantro media driver supports Rockchip and NXP SoCs including the RK3399 used in the Pinebook Pro and RockPro64. In November 2020 it was announced that Bootlin was working on encoding support for the driver.
H264 video decoding is possible when using GStreamer built from source, or an application utilizing it such as Clapper or µPlayer. µPlayer includes a indicator of when hardware acceleration is properly working and in use.