Mainline Hardware Decoding
Mainline Hardware Decoding refers to video decoding done using hardware accelerators on the mainline Linux kernel (i.e. what sits in Linus' tree).
On most consumer-oriented SoCs, there is what is referred to as a VPU (Video Processing Unit). The VPU is responsible for power-efficient encoding and decoding of videos. Hardware-accelerated video decoding can be useful to get smoother video playback on your devices, lower power consumption, and lower CPU utilisation. Below is information regarding various hardware PINE64 uses and software that works with it.
Hardware
Here's a table of the current support for different hardware.
SoC Codec
|
RK3328 | RK3399 | RK3566 | RK3588 |
|---|---|---|---|---|
| JPEG | ? | Yes | In review | No |
| MPEG-2 | Yes | Yes | In review | No |
| VP-8 | Yes | Yes | N/A | N/A |
| H.264/AVC | In review | Yes | No | No |
| H.265/HEVC | In review | In review | No | No |
| VP-9 | In review | In review | No | No |
| AV1 | N/A | N/A | N/A | No |
Cedrus
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.
Hantro
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.
rkvdec
rkvdec is the video decoding hardware that's developed by Rockchip presumably in house. It's what Rockchip uses for decoding 4K H.264/AVC, VP-9 and H.265/HEVC content.
RK3566, RK3568 and likely RK3588 use a second generation of rkvdec called rkvdec2. No mainline driver for this exists yet.
Software
GStreamer
H.264 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.
FFmpeg
Mainline FFmpeg currently lacks the necessary patches to use the v4l2-requests based API, but a fork that can utilise it exists.
More Resources
HW accelerated GStreamer playback on the PinePhone
HW accelerated Clapper video player on the PinePhone