On Wednesday, March 25, 2020 9:50 AM, Neil Armstrong narmstrong@baylibre.com wrote:
Amlogic uses a proprietary lossless image compression protocol and format for their hardware video codec accelerators, either video decoders or video input encoders.
This introduces the Scatter Memory layout, means the header contains IOMMU references to the compressed frames content to optimize memory access and layout.
In this mode, only the header memory address is needed, thus the content memory organization is tied to the current producer execution and cannot be saved/dumped neither transferrable between Amlogic SoCs supporting this modifier.
I don't think this is suitable for modifiers. User-space relies on being able to copy a buffer from one machine to another over the network. It would be pretty annoying for user-space to have a blacklist of modifiers that don't work this way.
Example of such user-space: https://gitlab.freedesktop.org/mstoeckl/waypipe/